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Correlation between leaf age, shade levels, and characteristic beneficial natural constituents of tea (Camellia sinensis) grown in Hawaii
Abstract
This study showed the relationship between tea leaf age, bud and first two leaves, and shade levels, on the relative concentrations of six major compounds of tea leaf, namely l-theanine, caffeine, and the major tea catechins; (−)-epigallocatechin gallate (EGCG), (−)-epigallocatechin (EGC), (−)-epicatechin (EC), and (−)-epicatechin gallate (ECG), all of which are reported to have positive effects on human health, as well as at the ferric reducing antioxidant power of bud and leaf extracts. The concentration of l-theanine and caffeine decreased as leaf age increased moving from bud to first and then second leaf, while the concentration of the four catechins increased from the bud to first and second leaves. In most cases this increase was generally relatively small but in the case of EGC it was 7 to 10-fold. Certain chemical components of freshly picked, minimally processed and essentially unoxidised tea may potentially be used as markers for age, quality, authenticity and area of growth.
... Health benefits of tea in reducing risks of cardiovascular diseases, cancer, and obesity are highly related to the antioxidant activity of polyphenols (65). Catechins are the most abundant secondary metabolites in TP (66). Therefore, TP and catechins are important variables in the quality evaluation of tea. ...
... Therefore, TP and catechins are important variables in the quality evaluation of tea. Our results agreed with previous reports in that shade treatments increased EGCG, the most predominant constituent in catechins compared with no-shade control (30,66,67). Total concentration of secondary metabolites as well as the secondary metabolites constituents (metabolite profile) in tea leaves is influenced by plant genotype, environment, cultivation method, etc. (68). ...
... Higher levels of caffeine synthase, which is an important enzyme in the caffeine synthesis of tea plants, were found in summer than in spring (87), which might explain our results at the metabolic level. Black, blue, and red shades increased the caffeine content in tea leaves among spring, summer, and fall, which is inconsistent with previous studies (32,66,67,88). Although light is not an essential factor in the biosynthesis of caffeine, the higher levels of caffeine in tea leaves under shade treatments compared to no-shade control may result from the fact that light enhances the degradation of caffeine (89,90). ...
Shading modifies the microenvironment and can provide plants with some protection from frequent heat, drought, frost, and hail induced by climate change and has the potential to improve plant growth, yield, and quality. Tea (Camellia sinensis) is an ancient plant originating from tropical and subtropical regions and prefers to grow in partial shade under the forest canopy. The emerging tea industry in the United States (US) requires research support on establishing tea fields in novel environmental conditions as well as on producing high-quality tea products. This study investigated the effects of black, blue, and red shade nets on tea plant growth and seasonal leaf qualities in the southeastern US with a humid subtropical climate. When compared to no-shade control, black, blue, and red shade nets increased plant growth index (PGI), net photosynthetic rate (P n), and stomatal conductance (g s), decreased air and leaf surface temperatures in summer, and reduced cold damage in winter. No significant difference was found among the black, blue, and red shade nets on tea plant growth. Varying contents of total polyphenols, carbohydrates, free amino acids, L-theanine, gallic acid, caffeine, and catechins in fresh tea leaves were observed among different shade treatments and harvesting seasons. 69.58% of the variations were depicted in a biplot by principal component analysis. Red shade was considered helpful for improving green tea quality by increasing the content of L-theanine and free amino acids in tea leaves collected in spring and fall when compared to no-shade control.
... Tea is one of the most well known and most consumed beverages in the world, which provides both health benefits and economic value (Song et al., 2012;Lee et al., 2014;Zhu et al., 2020). Due to the benefits tea brings to health, the exploration of tea has increased at molecular level. ...
... Tea belongs to the Theaceae family, and is a quite important economically crop worldwide whose leaves can be used to produce various tea. Because of the variation of gene, the difference in growing conditions and the difference in processing modes, tea always has diverse palatability, like bitter, astringent, and sweet flavors (Song et al., 2012). Camellia sinensis var. ...
... Camellia sinensis var. sinensis (CSS) is one of the most widely distributed cultivars for quality green tea production (Song et al., 2012). Currently, 67% elite tea plant cultivars belong to CSS. ...
Genes that have no homologous sequences with other species are called lineage-specific genes (LSGs), are common in living organisms, and have an important role in the generation of new functions, adaptive evolution and phenotypic alteration of species. Camellia sinensis var. sinensis (CSS) is one of the most widely distributed cultivars for quality green tea production. The rich catechins in tea have antioxidant, free radical elimination, fat loss and cancer prevention potential. To further understand the evolution and utilize the function of LSGs in tea, we performed a comparative genomics approach to identify Camellia -specific genes (CSGs). Our result reveals that 1701 CSGs were identified specific to CSS, accounting for 3.37% of all protein-coding genes. The majority of CSGs (57.08%) were generated by gene duplication, and the time of duplication occurrence coincide with the time of two genome-wide replication (WGD) events that happened in CSS genome. Gene structure analysis revealed that CSGs have shorter gene lengths, fewer exons, higher GC content and higher isoelectric point. Gene expression analysis showed that CSG had more tissue-specific expression compared to evolutionary conserved genes (ECs). Weighted gene co-expression network analysis (WGCNA) showed that 18 CSGs are mainly associated with catechin synthesis-related pathways, including phenylalanine biosynthesis, biosynthesis of amino acids, pentose phosphate pathway, photosynthesis and carbon metabolism. Besides, we found that the expression of three CSGs ( CSS0030246 , CSS0002298, and CSS0030939 ) was significantly down-regulated in response to both types of stresses (salt and drought). Our study first systematically identified LSGs in CSS, and comprehensively analyzed the features and potential functions of CSGs. We also identified key candidate genes, which will provide valuable assistance for further studies on catechin synthesis and provide a molecular basis for the excavation of excellent germplasm resources.
... Growing plants under a canopy or in the open habitat has a significant effect on the morphological and metabolic phenotypes of the plants [24]. This can be attributed to the changes in environmental factors such as light conditions [25] and soil conditions [26]. Grapevines grown under canopy habitats were found to have a higher flower drop percentage and a lower level of some primary metabolites in its inflorescences [27]. ...
... Another study suggested that these effects differ among species [33]. In addition, the phenotype differences in plants grown under canopy habitats and open habitats can also be contributed by soil condition differences [26]. This is because soil conditions such as soil nitrogen content [34,35] and soil humidity [36] are also key factors that affect plant growth. ...
... These results are consistent with results obtained from a study done on soybean where the general photosynthetic capacity was decreased despite the reduced light leading to higher light capture ability of soybean [30]. In addition, a study has reported that the soil properties are affected in native under canopy habitats which could affect the growth and development of plants [26]. The obtained results indicated that soil humidity, soil total nitrogen content, and soil organic carbon content were higher at under canopy habitats (Fig. S3), and the differences in soil organic carbon and soil total nitrogen contents between the two habitats were significant. ...
Background
Rheum tanguticum (Rh. tanguticum) is an important traditional Chinese medicine plant, “Dahuang”, which contains productive metabolites and occupies wide habitats on the Qinghai-Tibet plateau. Plants occupying wide habitats usually vary in phenotypes such as in morphology and metabolism, thereby developing into different ecotypes. Under canopy and open habitats are a pair of dissimilar habitats which possess Rh. tanguticum plants. However, few studies have focused on the effect of habitats on Rh. tanguticum growth, particularly combining morphological and metabolic changes. This study focused on Rh. tanguticum plants growing in under canopy and open habitats where morphology and metabolism changes were quantified using non-target metabolism methods.
Results
The obtained results indicated that the two dissimilar habitats led to Rh. tanguticum developing into two distinct ecotypes where the morphology and metabolism were simultaneously changed. Under canopy habitats bred morphologically smaller Rh. tanguticum plants which had a higher level of metabolites (22 out of 31) which included five flavonoids, four isoflavonoids, and three anthracenes. On the other hand, the open habitats produced morphologically larger Rh. tanguticum plants having a higher level of metabolites (9 out of 31) including four flavonoids. 6 of the 31 metabolites were predicted to have effect targets, include 4 represent for under canopy habitats and 2 for open habitats. Totally, 208 targets were connected, among which 42 were communal targets for both under canopy and open habitats represent compounds, and 100 and 66 were unique targets for under canopy superior compounds and open habitats superior compounds, respectively. In addition, aloe-emodin, emodin, chrysophanol, physcion, sennoside A and sennoside B were all more accumulated in under canopy habitats, and among which aloe-emodin, emodin, chrysophanol and physcion were significantly higher in under canopy habitats.
Conclusions
This study determined that Rh. tanguticum growing in under canopy and in open habitats developed into two distinct ecotypes with morphological and metabolic differences. Results of network pharmacology study has indicated that “Dahuang” coming from different habitats, such as under canopy and open habitats, are different in effect targets and thus may have different medicinal use. According to target metabolomics, under canopy habitats may grow better “Dahuang”.
... One such strategy is growing plants under shade. This improves the quality of fresh leaves through the enhancement of chlorophyll accumulation and the balancing of secondary metabolites (Song et al., 2012;Wang et al., 2012;. The leaves of tea plants grown under shade conditions contain a higher level of chlorophylls (Liu G. F. et al., 2017;, which contributes to a bright green color of the product (Wang et al., 2012). ...
... In addition to color improvement of the tea infusion, the shaded leaves contain high levels of amino acids but lower catechin content, which also improves the sensory qualities (Wang et al., 2012;Lu et al., 2014). Studies on the effect of shade on the tea plants were initiated decades ago, with major systematic analyses focused on the influence of secondary metabolites, such as catechin and flavonol biosynthesis (Koretskaya and Zaprometov, 1975;Saijo, 1980;Song et al., 2012). However, little attention has been paid to the mechanisms of regulation of chlorophyll biosynthesis by light when referring to the interplay between light and hormones. ...
... Evidence from previous studies indicates that the reduction of light exposure enhances chlorophyll accumulation in tea leaves (Song et al., 2012;Wang et al., 2012;. However, the molecular mechanisms for chlorophyll biosynthesis are still mysterious, especially when referring to the interplay between light and hormones under shade conditions. ...
Chloroplast development and chlorophyll metabolism have been well described in model plants but not in perennial woody crops. Of particular interest is the interplay between light and hormones under shade conditions. We report that the shade induced accumulation of chlorophylls in Camellia sinensis cv. Shuchazao leaves is at least as a result of (a) positive changes in chloroplast development and (b) light/hormonal regulation of genes and transcription factors involved in the chlorophyll biosynthesis pathway. Under shade conditions, leaves developed an abundance of enlarged chloroplasts encapsulating more prominent thylakoid membranes. Four major metabolites in the chlorophyll biosynthesis pathway namely Chl a, Chl b, DPP, and Mg-Proto IX increased under shade conditions while PBG decreased significantly. Significant changes were found at the transcription level of regulators of chloroplast biogenesis (GLK1 and LHCB), the structural genes in the chlorophyll biosynthesis pathway (HEMA1, CLH1, PORA, and CAO) and potential components involved in light signaling (PHYA, CRY1, HY5, and DELLAs). Two central signal integrators (GLK1 and LHCB) between the nucleus and chloroplast showed clear responses to shade, suggesting a crucial role of light in regulating chloroplast development in tea leaves. Concurrent with the changes in gene expression, the concentrations of endogenous phytohormones (auxin, cytokinin, and gibberellins) increased significantly in the later stages of shade conditions. Two key integrators involved in the hormone signal pathways, EIN3 and EBF1/2, increased under shade conditions suggesting that shade induced changes to hormone levels may play some role in modulating chlorophyll biosynthesis in the tea leaves. Overall, this data suggests that the light and hormone influence over chloroplast development and chlorophyll biosynthesis in Camellia is similar to that of Arabidopsis. This study provides new insights into the molecular mechanisms that regulate chlorophyll biosynthesis in response to light and hormones in a commercially important woody plant such as Camellia, which may facilitate the breeding of high-chlorophyll tea cultivars for the improvement of sensory features of the green tea product.
... Moreover, the epigallocatechin and catechin contents of young shoot tea leaves grown in the shade area are lower if covered. It has been reported that the levels of epicatechin increased from the bud to the second leaf [28,29]. In addition, catechin has been reported to be highly influenced by the various storage conditions [8]. ...
... High temperatures responded to a higher yield of caffeine. In addition, the age of green leaves is also a very important factor, as young leaves contain higher caffeine contents when compared to old leaves [1,28,34]. For instance, the levels of caffeine in green teas ranged between 26.7-38.1 mg/g at the extraction conditions of 80 • C and 20 min [3]. ...
This study investigates the effects of in vitro digestion on the antioxidant activity and release of phenolics, xanthine alkaloids, and L-theanine contents of matcha. It establishes digestibility values between 61.2–65.8%. Considering native matcha, the rutin content (303–479 µg/g) reached higher values than catechin (10.2–23.1 µg/g). Chlorogenic acid (2090–2460 µg/g) was determined as predominant. Rutin, quercetin, ferulic, ellagic, and caffeic acid were the least-released phenolics, and their remaining residues reached 76–84%. Protocatechuic, hydroxybenzoic acid, epigallocatechin, and epigallocatechin-3-gallate were the best-released phenolics, with the remaining residues under 1%. Caffeine, L-theanine, and theobromine contents in native matcha reached 16.1, 9.85, and 0.27 mg/g, respectively. Only caffeine (3.66–5.26 mg/g) and L-theanine (0.09–0.15 mg/g) were monitored in the undigested residue, representing 13 and 0.1% of the remaining part, respectively. A chemiluminescence assay showed that water-soluble antioxidants showed significant antioxidant activity in native matcha, while lipid-soluble compounds showed higher antioxidant activity in the undigested samples. Cinnamic and neochlorogenic acids were determined as the main contributors to the ACW values in the undigested matcha, epicatechin, and quercetin in the ACL fraction. The application of the digestion process reduced the antioxidant activity by more than 94%. SEM has proved specific digestion patterns of in vitro digestibility of matcha.
... The height of the measurement results is influenced by air temperature, sunlight and rain intensity at two different measurement times ( Figure 1). Shade can control plant growth, reduce light intensity and modify microclimates such as air temperature, soil temperature, air humidi-ty, carbon dioxide concentration and air ve-locity [7], [8], [9]. Xu et al. [10] also report-ed that shading reduced daily air tempera-ture, soil temperature, and light intensity by 2.31%, 2.67% and 18.45% in 2014, and 2.47%, 2.44% and 21.34% in 2015; RH in shade was higher than without shade. ...
Swiss chard is a leafy vegetable that is high in nutrients, vitamins, minerals, protein, and antioxidants that are beneficial to human health. Swiss chard. Swiss chard is generally cultivated in the Mediterranean climate, grows well in full sunlight, air temperatures 14-21oC, and can still survive at temperatures close to light frost. The aim of this study to evaluate efficient plant densi-ties in urban limited land area and looking at the response of Swiss chard plant to reduc-ing the intensity of sunligt of 45%, 55% and 80%.in urban tropic area. This research was used 4 different artificial shading i.e 0% (control, shade 45%, shade 55% and shade 80%. Microclimate was measured per each shade for 14 days i.e., air temperatur, soil temperature, air humidity, and soil moisture using a data logger meter. Shade with intensity 80% is proven to reduce air temperate and soil temperature, but also inhibits the growth and development of Swiss chard plants. Population 1plant/pot gives the best growth and yield of Swiss chard per plant, 3 plants/pot increased total fresh weight per cultivation area, thereby maximize the use of limited urban land
... The limiting factor in developing citronella as an intercrop in agroforestry systems is the unavailability of optimum sunlight, which can deteriorate essential oils' growth and quality. The shade negatively affects light accessibility and other agro-climatic conditions, e.g., air temperature, soil temperature, humidity, and CO2 concentration (Song et al. 2012). The shade also leads to diminished stomatal conductivity, inhibited CO2 transport, and low transpiration, decreasing nutrient distribution and assimilated yields (Shafiq et al. 2021). ...
Danata NH, Aini N, Udayana C, Setiawan A, Yamika WSD, Prambudi R. 2023. Diversity characterization of three varieties of Cymbopogon nardus under different shade conditions. Biodiversitas 24: 3574-3582. Cymbopogon nardus L. is a perennial aromatic plant distinguished for producing one of the world's most vital essential oils, citronella. This plant requires abounding sunlight to maximize the growth and quality of essential oils. The development of citronella can be implemented with an agroforestry system as an intercrop. However, the deterring factor restricting the propagation of citronella as an intercrop in agroforestry systems is the unavailability of adequate sunlight, consequently deteriorating the growth and quality of essential oils. This study investigated three varieties of C. nardus, i.e., Seraiwangi 1, Sitrona 1 Agribun, and Sitrona 2 Agribun, at distinctive shade proportions, i.e., 0%, 25%, 50%, and 75% shade. The examined parameters included the growth, physiological responses, yield, and quality of essential oils, i.e., citronellal, citronellol, and geraniol. Results demonstrate that the various types and shade percentages affect most examined parameters. The Seraiwangi 1 variety grown under 0% and 25% shade had nearly the same value, while the Sitrona 1 Agribun and Sitrona 2 Agribun varieties continued to experience declines ranging from 0%, 25%, 50%, to 75%. Nevertheless, shade extensively influences physiological responses such as photosynthetic rate and stomata width, and contrastingly there was a cipher effect on the stomata length. In the yield parameters, the oil concentration declined with the increase in shading percentage. The Seraiwangi 1 delivered superior quality of citronellal, citronellol, and geraniol compared to Sitrona 1 Agribun and Sitrona 2 Agribun varieties.
... In contrast, more flavonoids and lutein are formed in tea plants under a strong light to resist stress [6,7]. Suitable light conditions are considered to be an important prerequisite for a high yield and good quality of tea in production [5,8]. Limited by geographical location, climate, and vegetation, natural light conditions are not guaranteed to be optimal for tea production [9,10]. ...
Low-temperature stress limits global tea planting areas and production efficiency. Light is another essential ecological factor that acts in conjunction with temperature in the plant life cycle. However, it is unclear whether the differential light environment affects the low temperature adaptability of tea plant (Camellia sect. Thea). In this study, tea plant materials in three groups of light intensity treatments showed differentiated characteristics for low-temperature adaptability. Strong light (ST, 240 μmol·m−2·s−1) caused the degradation of chlorophyll and a decrease in peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and polyphenol oxidase (PPO) activities, as well as an increase in soluble sugar, soluble protein, malondialdehyde (MDA), and relative conductivity in tea leaves. In contrast, antioxidant enzyme activities, chlorophyll content, and relative conductivity were highest in weak light (WT, 15 μmol·m−2·s−1). Damage was observed in both ST and WT materials relative to moderate light intensity (MT, 160 μmol·m−2·s−1) in a frost resistance test. Chlorophyll degradation in strong light was a behavior that prevented photodamage, and the maximum photosynthetic quantum yield of PS II (Fv/Fm) decreased with increasing light intensity. This suggests that the browning that occurs on the leaf surface of ST materials through frost may have been stressed by the previous increase in reactive oxygen species (ROS). Frost intolerance of WT materials is mainly related to delayed tissue development and tenderness holding. Interestingly, transcriptome sequencing revealed that stronger light favors starch biosynthesis, while cellulose biosynthesis is enhanced in weaker light. It showed that light intensity mediated the form of carbon fixation in tea plant, and this was associated with low-temperature adaptability.
... Ethylamine level is considered as the limiting factor for theanine biosynthesis (Cheng et al. 2017). The theanine content of young tea shoots is increased with shade level (Song et al. 2012). In the shading-treated tea plants, the level of ethylamine in the roots was significantly increased due to the up-regulated expression of CsAlaDC . ...
Matcha, a powder processed from tea leaves, has a unique green tea flavor and appealing color, in addition to many other sought after functional properties for a wide range of formulated food applications (e.g., dairy products, bakery products, and beverage). The properties of matcha are influenced by cultivation method and processing post-harvest. The transition from drinking tea infusion to eating whole leaves provides a healthy option for the delivery of functional component and tea phenolics in various food matrix. The aim of this review is to describe the physico-chemical properties of matcha, the specific requirements for tea cultivation and industrial processing. The quality of matcha mainly depends on the quality of fresh tea leaves, which is affected by preharvest factors including tea cultivar, shading treatment, and fertilization. Shading is the key measure to increase greenness, reduce bitterness and astringency, and enhance umami taste of matcha. The potential health benefits of matcha and the gastrointestinal fate of main phenolics in matcha are covered. The chemical compositions and bioactivities of fiber-bound phenolics in matcha and other plant materials are discussed. The fiber-bound phenolics are considered promising components which endow matcha with boosted bioavailability of phenolics and health benefits through modulating gut microbiota.
... Instructions for Authors 91 ...
Throughout human history, there have been several pandemics that caused a huge loss to humanity. Most famous of these include the 14th-century black death (estimated 75-200M deaths) 1918 Spanish flu ( 50M) 1957-58 swine Flu (estimated 2M) 1968 Hong Kong flu (estimated 1M) 2009-10 Swine flu ( 150 000-500,000), etc. Responding to or planning for a pandemic is a complex process. The most important global pandemic preparedness indicators take account of prevention for the emergence or release of the potential pathogens, early detection and assessing their expansion, emergency response, global risk mitigation, strong healthcare system, commitment to improving national capacity in compliance with the global needs an overall assessment of country’s vulnerability to risk/biological threat. The COVID-19 has proved that more work needs to be done for preparedness and countermeasures of possible pandemics. At the same time, in the era of information technology, one has to use social media for the good of humanity. Unfortunately, the use of social media has been counterproductive in the current pandemic. UNESCO estimates that over 1.5 billion students in 165 countries are out of school due to COVID-19. The pandemic has forced the global academic community to explore new ways of teaching and learning, including distance and online education. This has proven challenging for both students and educators, who have to deal with the emotional, physical, and economic difficulties posed by the illness while doing their part to help curb the spread of the virus. The future is uncertain for everyone, particularly for millions of students scheduled to graduate this year who will face a world crippled economically by the pandemic. To deliberate upon the gigantic role of scientists, researchers, medical practitioners, policymakers, students, media, etc. and to arrive at possible strategies, AASSA-PAS Webinar Series 2021 on Pandemic Preparedness: Science and Countermeasures were organized jointly by the Pakistan Academy of Sciences (PAS) and the Association of Academies and Societies of Sciences in Asia (AASSA) with the support of InterAcademy Partnership (IAP) consisting of four (04) webinars each covering a specific theme of the current pandemic scenario/situation and scheduled on April 27, 2021, May 4, 2021, May 25, 2021, and June 24, 2021. The webinar series has provided an opportunity to share lessons learnt among the participating countries and scientists about the Covid-19 and its relation to sustainable development goals; Strategy of the current issues, challenges while facing pandemics; and the increasing awareness about the preparedness of the future pandemics. Use of emerging technologies like Artificial Intelligence Applications in Tracking Health Behaviors during Disease Epidemics and Encouraging the use of ICT technologies and social media for tackling the spread of misinformation regarding different aspects of the pandemic were discussed besides Pandemic: Bio-safety & Biosecurity and Ethics. In total, 48 lectures were delivered in the AASSA-PAS Webinar series 2021 by leading experts. Of these, eighteen (18) lectures were presented by the international speakers and thirty (30) lectures were presented by the Pakistani speakers. The resource persons in the Webinars were leading foreign experts from different countries i.e., Australia, Bangladesh, China, Indonesia, Iran, Japan, Korea, Kyrgyzstan, Malaysia, Nepal, Pakistan, Russia, Turkey, United Arab Emirates (UAE), USA, and Vietnam. More than 2000 national and international participants registered for participation in the AASSA-PAS Webinar series 2021. These include 748 participants in Webinar I, 760 participants in Webinar II, 428 participants in Webinar III, and more than 300 in Webinar IV.
... The contents of soluble sugar and caffeine increased significantly (p < 0.01), while the content of free amino acids markedly decreased in black tea processed from spring to summer; the same variation in the compound contents was observed in both Hy and Yh (Table 1), and the results are consistent with previous studies [10,36]. Much research revealed that caffeine synthesis increased in response to increased light intensity; however, amino acids were contrary to caffeine [37][38][39]. The content of sugar in Hy in summer and autumn decreased by 25.29% and 19.19% compared with that in Yh, respectively ( Table 1). ...
Harvesting seasons are crucial for the physicochemical qualities of large-leaf-variety black tea. To investigate the effect of harvesting seasons on physicochemical qualities, the color and sensory characteristics of black tea produced from “Yinghong 9” (Yh) and its mutant “Huangyu” (Hy) leaves were analyzed. The results demonstrated that Hy had better chemical qualities and sensory characteristics, on average, such as a higher content of tea polyphenols, free amino acids, caffeine, galloylated catechins (GaCs) and non-galloylated catechins (NGaCs), while the hue of the tea brew (ΔE*ab and Δb*) increased, which meant that the tea brew was yellower and redder. Moreover, the data showed that the physicochemical qualities of SpHy (Hy processed in spring) were superior to those of SuHy (Hy processed in summer) and AuHy (Hy processed in autumn), and 92.6% of the total variance in PCA score plots effectively explained the separation of the physicochemical qualities of Yh and Hy processed in different harvesting seasons. In summary, Hy processed in spring was superior in its physicochemical qualities. The current results will provide scientific guidance for the production of high-quality large-leaf-variety black tea in South China.
... Those months were marked by high average maximum temperature and solar radiation indexes. Same trend was reported by (Song et al., 2012) which demonstrated that the leaves of C. sinensis when grown under shade showed higher amounts of theanine when compared to those that grew under full sun. According to (Ku et al., 2010), the increase in theanine concentration under shade treatment conditions may be related to the increase in nitrogen assimilation, and to the reduction of catabolism of this amino acid under shaded cultivation. ...
Green tea is a product obtained from the processing of fresh leaves of Camellia sinensis (L.) Kuntze species. In this study, the influence of climatic parameters on the chemical composition of green tea cultivars ('Yabukita' and 'Yutakamidori) over the harvest was evaluated using HR-MAS NMR. 'Yabukita' showed higher concentrations of epicatechin while higher amounts of theanine and caffeine were found in 'Yutakamidori'. The decline of theanine was associated with high average maximum temperature and solar radiation index, this latter also seemed to be responsible for relevant changes in epicatechin concentrations. It was not possible to associate any trend between climatic parameters and caffeine concentration. Fluctuations in linolenic acid concentration were monitored during the harvest period and were associated with the plant's defense mechanism. Monitoring of green tea over seasons and correlating the fluctuations of compounds to climatic parameters might become an efficient strategy for establishing quality standards for green teas.
... The genes responsible for caffeine production in the leaf might have got inhibited that affected the caffeine content of the leaves. This study corroborates the findings of Song et al. [22] reported that the total caffeine content of green leaves of tea crop decreased with an increase in temperature. ...
Assam is known worldwide for its production of tea; the state contributes around 52 percent to the India’s tea production.Similar to tea, crude oil operations date back to the 19th century and accounts for about 15 percent of India’s crude output, thus making these sectors important economically. However apart from the positive effects, crude oil operations result in gas flaring, which is already recognized as an environmental problem. Taking into context the harmful effects of gas flaring the present investigation aims to study the impact of gas flaring on physiological parameters of tea plant with respect to growth adjacent to oil field in Merbil Majuli OCS 6(WEST) in Dibrugarh district of Assam during 2019-2020. The study was designed with Randomized Complete Block Design (RCBD) accommodating five levels under distance and two levels under seasons. Plant samples were collected at random intervals and estimated for plant physiological parameters such as water saturation deficit(WSD),relative turgidity, stomatal count, polyphenol content, specific leaf weight, caffeine content, chlorophyll content, plucking point density. The present study found that gas flaring had a significant effect on the physiology of the tea crop in terms of growth. The study found a gradual decrease in relative turgidity, specific leaf weight, plucking point density, stomatal count, leaf area measurement, polyphenol content, chlorophyll content, caffeine content, but an increase in water saturation deficit of green tea leaves on plants growing closer to the flare pit.
... The growth of plants was best in OH because uninterrupted light is considered an important factor promoting the initial growth of plant than soil nutrients and water because soil fertility and moisture can be manipulated but light is the most important factor in climate which is more difficult to control (Dai et al. 2009;Zhao et al. 2012;Latha & Radhakrishnan 2015;Dev et al. 2018;Saran et al. 2019). Growth of plants depend on photosynthate which is directly related to amount of sun light received by the plant in different growing conditions (Bertamini et al. 2006); plants in shade or partial shade, not only affect the amount of light that is essential for photosynthesis but influence micro-environmental conditions, such as soil temperature, moisture, humidity and carbon-dioxide concentration (Song et al. 2012). Reduction in growth under shade is governed by lesser light interception and relative irradiances (Cockshull et al. 1992;Valio 2001). ...
Hygrophila auriculata (Schumach.) Heine is an underutilized medicinal herb and is native to Indian subcontinent. Very little research has been reported on the species. The species produces seeds with poor viability and low germination; thereby, vegetative propagation techniques are the best alternative. The present study was an attempt to standardize growing media for better rooting and survival of stem cuttings of the species including its growth performance under different shade intensities in the sub-humid region of West Bengal. The growing media composition with FYM was found better for initial seedling survival due to successful root formation. Growth of the species was similar with no shade and 50 % shade indicating suitability of the species as an under-storey crop in agroforestry systems. However, influence of shade on composition of active ingredients needs to be analysed before recommending the species under agroforestry systems in the sub-humid foot-hill conditions of Eastern Himalayas.
... The effect of caffeine reduction with leaf age has already been observed in some studies with different plants [34,35]. Song et al. [36] explained this effect mainly by the function of caffeine as a pesticide. Younger leaves of the plant must be more protected compared to old ones; therefore, the plant builds up higher concentrations in those leaves. ...
The production of coffee leaf tea (Coffea arabica) in El Salvador and the influences of processing steps on non-volatile compounds and volatile aroma-active compounds were investigated. The tea was produced according to the process steps of conventional tea (Camellia sinensis) with the available possibilities on the farm. Influencing factors were the leaf type (old, young, yellow, shoots), processing (blending, cutting, rolling, freezing, steaming), drying (sun drying, oven drying, roasting) and fermentation (wild, yeast, Lactobacillus). Subsequently, the samples were analysed for the maximum levels of caffeine, chlorogenic acid, and epigallocatechin gallate permitted by the European Commission. The caffeine content ranged between 0.37–1.33 g/100 g dry mass (DM), the chlorogenic acid was between not detectable and 9.35 g/100 g DM and epigallocatechin gallate could not be detected at all. Furthermore, water content, essential oil, ash content, total polyphenols, total catechins, organic acids, and trigonelline were determined. Gas chromatography—mass spectrometry—olfactometry and calculation of the odour activity values (OAVs) were carried out to determine the main aroma-active compounds, which are β-ionone (honey-like, OAV 132-927), decanal (citrus-like, floral, OAV 14-301), α-ionone (floral, OAV 30-100), (E,Z)-2,6-nonadienal (cucumber-like, OAV 18-256), 2,4-nonadienal (melon-like, OAV 2-18), octanal (fruity, OAV 7-23), (E)-2 nonenal (citrus-like, OAV 1-11), hexanal (grassy, OAV 1-10), and 4-heptenal (green, OAV 1-9). The data obtained in this study may help to adjust process parameters directly to consumer preferences and allow coffee farmers to earn an extra income from this by-product.
... 4 The health benets of tea are mainly due to the fact that it contains a large number of physiologically active ingredients, such as tea polyphenols, theanine, and caffeine. 5,6 Tea polyphenols are one of the most important physiologically active substances in tea, 7 it has unique pharmacological properties to prevent cancer, cardiovascular disease, neurodegenerative diseases and other diseases, 8 studies have shown that in neurodegenerative diseases, oxidative stress in Alzheimer's disease is its underlying pathological mechanism, possibly due to an imbalance of reactive oxygen species and antioxidant molecules, and the antioxidant properties of catechin can be relieved to a certain extent. 8 In addition, catechin inhibits tumor growth and carcinogenesis, as well as the release of tumor necrosis factor, due to its antioxidant properties, can play a protective role in low density lipoprotein antioxidant and antiatherosclerosis. 9 Theanine is a unique non-protein amino acid that accounts for about 50% of the amino acids in tea leaves and is one of the main components that form the avor of tea soup. ...
The health benefits of drinking tea stem from it being rich in polyphenols and other physiologically-active substances. Thus, exploring the synergistic effect between polyphenols and a variety of physiologically-active substances can contribute to our understanding of how tea benefits health. In this work, we have studied the interactions between catechin and theanine, exploring the synergetic antioxidant mechanism of the two molecules. Electrochemical characterization results showed that the oxidation peak current of catechin decreased gradually with the concentration of theanine, which is due to theanine spontaneously binding to catechin through intermolecular hydrogen bonds and forming molecular clusters via two hydrogen bonds. The binding constant is 4.75 at room temperature. The molecular clusters reduce the diffusion coefficient of catechin in solution, leading to the slow release of its antioxidant capacity (ability to effectively inhibit free radical oxidation reactions). Density functional theory calculations were also performed and verified the binding behavior. In identifying the synergistic effect between catechin and theanine on the antioxidant capacity of tea, this study adds to our understanding of the efficacy of tea polyphenols.
... This might be due to drought stress that inhibited the expression of genes related to caffeine biosynthesis and thereby reducing the accumulation of Caffeine in Camellia sinensis. This corroborates the findings of Song [18], Lee [19] and Zhang [20] who reported caffeine levels decreased with an increase in light. ...
Effect of gas flaring on physiology and growth of tea plants was done by using Randomized Complete Block Design (RCBD) and analysis was done accommodating two seasons and five levels of distances during September 2019-March 2020. Plant samples were collected from (40-50) metres, (50-60) metres, (60-70) metres, (70-80) metres and control site (150-160) metres away from the tea garden situated south of kothaloni OCS in rainy and autumn seasons. The experimental plot was laid out at a distance of 40 metres away from the flare pit. The mean value of plant parameters namely relative turgidity, tea leaf area ,specific leaf weight, stomatal count, caffeine content, chlorophyll content, polyphenol content and plucking point density were decreased near the gas flaring while mean value of water saturation deficit of tea leaves recorded highest at distances closest to the flaring site.
... These chemical compounds intrinsically determine the sensory quality and nutritional value of BT [5]. As suggested in previous works, the chemical composition of tea is largely influenced by tea varieties [6], shoot maturity [7], manufacturing technology [8], growing environment [9], and so on. Zhu et al. showed that green tea made from Yunnan Camellia taliensis contains high content of catechins and special hydrolysable tannins (1,2 di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-β-d-glucopyranose) [10]. ...
Ancient bud black tea (ABBT) is a special kind of black tea (BT) made from the bud of ancient tea tree. However, there is limited information about its chemical composition and the effects of shoot maturity and fermentation. By UHPLC-HRMS, 208 compounds including catechins, flavonoids, phenolic acids, alkaloids and others were qualitatively and quantitatively analyzed in ABBT. By comparison with traditional BT made from one bud with multiple leaves, it was suggested that the shoot maturity has great effects on the chemical profile of BT. Most of the detected compounds exhibited lower content in ABBT, while only a little number of compounds (e.g., theaflavin-3′-gallate, theaflavin-3-gallate, theaflavin-3,3′-gallate, quercitrin, isoquercitrin, and quinic acid) showed significantly higher contents in ABBT. During fermentation, the contents of these compounds varied obviously but with inconsistent trends. Simple catechins (e.g., EC, EGCG), dimers of catechins and their derivatives (e.g., prodelphinidin B2) showed an inconsistent decreasing trend, while oxidative polymerization products such as theaflavin-3,3′-gallate and theasinensin A showed a continuous increasing trend of content. Additionally, the contents of free phenolic acids, flavonoids, caffeine and amino acids showed a decreasing trend of content, while acylated phenolic acids exhibited an opposite trend. As a result, this work revealed the chemical profile of ABBT and enhanced our understanding with respect to the effects of shoot maturity and fermentation.
... The effect of caffeine reduction with leaf age has already been observed in some studies with different plants, e.g., Ilex paraguariensis and Plantago lanceolata [38,39]. Song et al. [40] explained this effect mainly by the function of caffeine as a pesticide. Younger leaves of the plant must be more protected compared to older ones; therefore, the plant builds higher concentrations in these leaves. ...
Coffee leaf tea is prepared as an infusion of dried leaves of Coffea spp. in hot water. It is a traditional beverage in some coffee-producing countries and has been authorized in 2020 within the European Union (EU) according to its novel food regulation. This article reviews current knowledge on the safety of coffee leaf tea. From the various ingredients contained in coffee leaves, only two were highlighted as possibly hazardous to human health, namely, caffeine and epigallocatechin gallate (EGCG), with maximum limits implemented in EU legislation, which is why this article focuses on these two substances. While the caffeine content is comparable to that of roasted coffee beans and subject to strong fluctuations in relation to the age of the leaves, climate, coffee species, and variety, a maximum of 1–3 cups per day may be recommended. The EGCG content is typically absent or below the intake of 800 mg/day classified as hepatotoxic by the European Food Safety Authority (EFSA), so this compound is suggested as toxicologically uncritical. Depending on selection and processing (age of the leaves, drying, fermentation, roasting, etc.), coffee leaf tea may exhibit a wide variety of flavors, and its full potential is currently almost unexplored. As a coffee by-product, it is certainly interesting to increase the income of coffee farmers. Our review has shown that coffee leaf tea is not assumed to exhibit risks for the consumer, apart from the well-known risk of caffeine inherent to all coffee-related beverages. This conclusion is corroborated by the history of its safe use in several countries around the world.
... Low germination synchrony is common in xeric plant species and has been linked to desert population persistence (Song et al., 2012;Lozano-Isla et al., 2018;Nimac et al., 2018;Bhatt et al., 2020a). In the present study, individuals within the population showed significant variation in MGT, depending on the species. ...
Coastal desert vegetation of the Arabian Peninsula is almost entirely dominated by halophytes. Natural populations provide a genetic resource for ecological remediation and may also have direct economic value. High intrapopulation variation of seed traits is presumed to increase population persistence in the unpredictable climatic conditions of this hyper-arid desert. We investigated whether intrapopulation variation of seed mass, dormancy and germinability of four species was attributable to maternal individuals. Arthrocnemum macrostachyum, Halothamnus iraquensis, Haloxylon salicornicum and Seidlitzia rosmarinus are commonly distributed Arabian halophytes with differing seed weight variation. All species exhibited a higher germination when exposed daily to 12 hours light, compared to seeds in darkness. A higher germination was correlated with a shorter germination time. For H. iraquensis and S. rosmarinus a shorter germination time was negatively correlated with germination synchrony. H. salicornicum showed the highest intrapopulation variation of seed traits, followed by A. macrostachyum, S. rosmarinus and H. iraqensis. We found that individuals within populations of all the studied species showed variability in germination but the extent of variation was species specific. The variation in seed mass and germination among the individuals of the studied species may facilitate a temporal distribution of germination, which may reduce the risk of seed bank exhaustion. The results of this study could assist conservation and management by improving the efficiency of seed collection from wild populations of these species.
... However, several studies have shown the influence of environmental conditions on flavan-3-ol content in other crops. Yao et al. showed in tea that the catechin contents were higher during warm months, 42 while the catechin and proanthocyanidin contents were not greatly affected by partial exclusion of solar radiation in tea 43 and grape berry 44 or by UV-B radiation in apples. 45 Although similar results had not been reported in cereals, variations in flavan-3-ol content could be more closely related to high-temperature stress than to changes in solar radiation. ...
Background
Barley (Hordeum vulgare L.) is a healthy grain due to high contents in dietary fiber and phenolic compounds. It faces periods of high temperatures during grain filling, frequently reducing grain weight. Heat stress may also affect some of the bioactive compounds present in the grain. To produce quality grains that provide nutritional and health benefits, it is important to understand the effect of environmental stresses on the quantity and quality of bioactive compounds.
Results
We have studied the effect of post‐anthesis thermal stress on barley bioactive compounds and antioxidant capacity under Mediterranean field conditions during two consecutive growing seasons in four barley genotypes. Thermal stress affected grain weight and size and changed the relative composition of bioactive compounds. The relationship between heat stress and grain β‐glucans and arabinoxylans content was indirect, as the resulting increases in concentrations were due to the lower grain weight under stress. On the contrary, heat stress had a significant direct impact on some phenolic compounds, increasing their concentrations differentially across genotypes, which contributed to an improvement in antioxidant capacity of up to 30%.
Conclusion
Post‐anthesis thermal stress had a significant effect on β‐glucans, arabinoxylans, phenolic compounds concentration and antioxidant capacity of barley grains. Final grain quality could be, at least partially, controlled in order to increase the bioactive concentrations in the barley grain, by cultivation in growing areas prone to heat stress. Late sowings or late flowering genotypes could also be considered, should a premium be implemented to compensate for lower yields.
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... 38−41 Indeed, several lines of evidence showed that shading increased theanine abundance in new shoots and leaves. 37,39,42,43 However, other studies reported that shading management did not significantly affect or actually reduce theanine accumulation in new tea shoots or leaves. 17,44,45 These studies have focused mainly on the theanine content in tea shoots, whereas few reports have paid attention to how shading might affect theanine synthesis in the roots and transport from roots to the shoot. ...
Shading was thought as an effective approach to increase theanine in harvested tea shoots. Previous studies offered conflicting findings, perhaps since the integration of theanine metabolism and transport in different tissues was not considered. Theanine is synthesized primarily in the roots and is then transported, via the vascular system, to new vegetative tissues. Here, we found that theanine increased in the stem, was reduced in the leaf, and remained stable in the roots, under shading conditions. Notably, in tea roots, shading significantly increased ethylamine and activated the theanine biosynthesis pathway and theanine transporter genes. Furthermore, shading significantly increased the expression of theanine transporter genes, CsAAP2/4/5/8, in the stem, while decreasing the expression of CsAAP1/2/4/5/6 in the leaf, in accordance with shading effects on theanine levels in these tissues. These findings reveal that shading of tea plants promotes theanine biosynthesis and allocation in different tissues, processes which appear to involve the theanine biosynthesis pathway enzymes and AAP family of theanine transporters.
... The EC and EGC contents demonstrated a significant increase from BGT to B2GT but an insignificant one from B2GT to B3GT. Song, Kelman, Johns, and Wright (2012) found that EC and EGC concentrations significantly increased from buds to the second leaf. In the present study, we found that the green tea made from tender tea shoot may have more positive properties than that made from mature tea shoot because catechins with galloyl moieties showed stronger antioxidant capacity than the ones without galloyl moieties (Hilal & Engelhardt, 2007). ...
Apart from geographical difference and processing method, the maturity of fresh tea shoot is an important factor that determines tea quality. However, the quality development and chemical variation of green tea with tea shoot maturity remain unclear. This study aimed to investigate the metabolic consequences of tea shoot maturity on the taste and aroma quality of green tea by metabolite profiling. In terms of taste quality, a concentration-dependent decrease with tea shoot age was observed in gallic acid and caffeine. The levels of catechin, epicatechin, and epigallocatechin increased with tea shoot maturity, whereas those of epicatechin gallate, epigallocatechin gallate, and total catechins decreased. Furthermore, the maximum contents of most amino acids were recorded in green tea processed from one bud with two leaves. In terms of aroma quality, volatile profiles of green tea were analyzed by gas chromatography–mass spectrometry combined with chemometrics. A total of 32 differential volatile organic compounds showing significant differences were identified and divided into Groups I and II, which contribute undesirable flavor and sweet flowery aroma to tea, respectively. The relative abundance of Group I increased with tea shoot maturity whereas that of Group II decreased. These findings can be used in guiding the production of green tea.
... The environment is one of the determining factors in plant growth in addition to genetic factors. The environment for plant growth is identical to the environment around the plant, both above ground and below ground (Song, Kelman, Johns, & Wright, 2012). ...
Biological agents such as rhizosphere bacteria and Vesicular Arbuscular Mycorrhiza (VAM) are potential agents to improve soil qualities. In addition, species and varieties of crops give different response to the shading related to their growth and development. The research aimed to determine the effect of biofertilizer application under different levels of shading conditions on the growth and capsaicin content of Capsicum frutescens L. and evaluate the suitable levels of shading. The research was conducted from February to June 2019 at Universitas Brawijaya. Bhaskara variety was chosen in this research. Thirteen treatments and three replications were arranged in the randomized design with nest pattern (Nested). The treatments were a combination between the shading level and biofertilizers. The dry weight, nutrient content, fresh weight and capsaicin content were observed. The results showed the application of biofertilizers consisted of PGPR and VAM consortium, under the lowest shading condition (25%) increased the total dry weight of chili, the nutrients absorption, and the capsaicin content. The capsaicin content is influenced by the fruit weight of chili and plant nitrogen uptake. Biofertilizers and the lowest shading conditions contribute to supporting the growth and development of chili pepper.
... Light is the energy basis for the survival of green plants, and it is also an important signal factor regulating various biological functions of plants [12]. Before picking the fresh tea leaves, shading method for limiting partial direct light can effectively reduce the bitter and astringent substances of tea [13][14][15][16]. Moreover, the discrepancies of light quality and photoperiod also affected the accumulation of avor substances and the formation of biological properties of tea leaves, such as the biosynthesis of avonoid and aroma volatiles [17,18], the conversion of leaf color [18], and the development of leaf and ower [18,19]. ...
Background: Tea plant (Camellia sinensis) is an important woody economic crop used for processing leaf-type beverages. Tea has been proved to be beneficial to human health because it is rich in tea polyphenols and other active ingredients. Numerous studies have shown that light is a necessary environmental condition to control the growth and metabolism of C. sinensis. Gene expression experiments are always performed to explore the transcriptional regulation mechanism of plants widely based on the technique of quantitative real time polymerase chain reaction (qRT-PCR). The screening and application of reference genes are necessary for the normalization of gene expression under specific conditions. However, the reference genes for systematic analysis of light-induced transcription mechanisms are still not available in C. sinensis.
Results: In this research, we identified actin family genes that are always used as reference genes with high frequency and without distinction for various expression experiments in C. sinensis. Six pairs of distinctive primers (corresponding to CsACT1, CsACT2, CsACT(3-4), CsACT(5-6), CsACT(7-8), and CsACT(9-10) genes) were designed to evaluate their expression stability in response to light quality (LQ), light intensity (LI), and photoperiod (PD). Simultaneously, six other family members (CsUBC1, CsCLATHRIN1, CsGAPDH, CsTBP, CsTIP41, and CseIF-4α) of C. sinensis commonly used as reference genes were also investigated. The stability rankings of gene expression were calculated by the statistical algorithms of geNorm, BestKeeper, NormFinder, and RefFinder softwares.
Conclusions: CsACT(5-6), CsTIP41, and CsACT(3-4) were the most stable genes for light quality (LQ), light intensity (LI), and photoperiod (PD) treatments, respectively. This study provides a basis for the selection of reference genes for future research on the transcription mechanism of light response in C. sinensis. Moreover, the analysis of actin family members of C. sinensis will help to understand the individual transcription mechanism of housekeeping family.
... O Matchá, obtido das folhas de Camellia sinensis, contém substâncias bioativas como flavonoides presentes na forma de catequinas (C) e ácidos fenólicos. Dentre elas, a epigalocatequina galato (EGCG) é o composto mais abundante e contribui com 50 a 80% do total das catequinas, usado como indicador na prevenção de doenças metabólicas, com propriedades fisiológicas e benéficas à saúde (ANANINGSIH; SHARMA; ZHOU, 2013;SONG et al., 2012). ...
... Additionally, we erected a 30 % shade cloth for the last 2 weeks of the experiment over plants in the wet treatment to reduce moisture loss. Shade may alter other conditions such as temperature and CO 2 concentration which influence plant growth (Song et al. 2012), and may confound the effects of water availability. However, the additional shade mimics field conditions, where patchy savanna tree cover ameliorates evaporation, and thus is relevant to creating wet versus dry environmental treatments. ...
Despite the ubiquity of introduced species, their long-term impacts on native plant abundance and diversity remain poorly understood. Coexistence theory offers a tool for advancing this understanding by providing a framework to link short-term individual measurements with long-term population dynamics by directly quantifying the niche and average fitness differences between species. We observed that a pair of closely related and functionally similar annual plants with different origins-native Plectritis congesta and introduced Valerianella locusta-co-occur at the community scale but rarely at the local scale of direct interaction. To test whether niche and/or fitness differences preclude local-scale long-term coexistence, we parameterized models of competitor dynamics with results from a controlled outdoor pot experiment, where we manipulated densities of each species. To evaluate the hypothesis that niche and fitness differences exhibit environmental dependency, leading to community-scale coexistence despite local competitive exclusion, we replicated this experiment with a water availability treatment to determine if this key limiting resource alters the long-term prediction. Water availability impacted population vital rates and intensities of intraspecific versus interspecific competition between P. congesta and V. locusta. Despite environmental influence on competition our model predicts that native P. congesta competitively excludes introduced V. locusta in direct competition across water availability conditions because of an absence of stabilizing niche differences combined with a difference in average fitness, although this advantage weakens in drier conditions. Further, field data demonstrated that P. congesta densities have a negative effect on V. locusta seed prediction. We conclude that native P. congesta limits abundances of introduced V. locusta at the direct-interaction scale, and we posit that V. locusta may rely on spatially dependent coexistence mechanisms to maintain coexistence at the site scale. In quantifying this competitive outcome our study demonstrates mechanistically how a native species may limit the abundance of an introduced invader.
... The compounds in each sample were identified and quantified by comparing their retention times and peak area in the chromatograms relative to external standards. The quantification of theanine was performed according to Song et al. (2012) at 200 nm. ...
Background
Green tea is not only one of the most widely consumed beverages worldwide, but is also known for its health promoting and therapeutic effects. Green tea is cultivated in areas with high humidity and acidic soils in China, Indonesia and Japan. Those places have well-marked dry and rainy seasons. In opposite, Azores have a climate with constant average annual rainfall and, unlike eastern regions, relatively constant air humidity throughout the year. While a brand implemented on the Portuguese market, the quality of green tea produced in Azores must be guaranteed. Quality control measures based on phytochemical determination of the chemical composition and biological activities are needed in order to address whenever climate changes interferes significantly with composition and biological effects.
Purpose
Make the phytochemical characterization of various extracts of green tea leaves coming from Azores and evaluate the anti-cancer activities of the extracts in order to compare the obtained results with those of teas coming from eastern regions.
Methods
Phytochemical characterization (catechins, oxyaromatic acids, flavonols, alkaloids and theanine), anti-radical activities (DPPH• IC50) and total phenolic contents (TPC) in infusions (5-7 min and 30 min), maceration and methanolic extracts of Camellia sinensis samples coming from Azores, Portugal was performed by using HPLC-DAD analysis and measurement of total catechins contents (TCC) measurements. The antioxidant activity was measured by the DPPH assay. The cytotoxic activity towards drug sensitive and multidrug-resistant leukemia cell lines was determined by the resazurin assay.
Results
The TCC was higher in methanolic extracts and lower in maceration, as epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) concentrations were significantly higher in methanolic extracts and were only residual in maceration extracts. Maceration extracts showed the highest content of gallic acid. This indicates that methanol extracts contained more flavonols of higher molecular weight and/or that maceration may lead to the degalloylation of catechins. The amount of o-caffeoylquinic acid extracted was significantly higher in methanolic samples. Short-term extraction at high temperatures resulted in high amounts of neochlorogenic acid. The contents of glycosylated quercitin-3-D-galactoside and kaempferol-3-glucoside were small in maceration samples and high in methanolic samples. Caffeine was easily extracted by methanol (99%) compared with water, while extraction of the amino-acid L-theanine was impossible with methanol. TPC values correlated linearly with DPPH• IC50, with infusion samples showing the best antioxidant capacities. The aqueous and the methanol/water extracts were active in multidrug-resistant and drug sensitive cancer cells.
Conclusion
Despite these climatic differences, the phytochemical characterization revealed that tea coming from the Azores compares well with those from China and Japan. In addition, tea can be produced without fungicides and pesticides to control pests that appear during rainy seasons. This allows the production of high-quality bioorganic tea. Aqueous and methanol/water extracts of the Azorean tea showed to be useful targeting sensitive and drug-resistant tumor cells.
... However, Harbowy et al. (2010) reported that the caffeine content of tea infusion may vary due to the cultivar, season, stage of plucking, geographical location, harvesting time and infusion conditions of the tea. It is also reported that tea shoots grown under shade contain more caffeine compared to those grown under the full sunlight (Song et al., 2012). Since low country has more shade trees (as high, medium and low) in tea fields with higher temperature, there is a possibility to contain higher caffeine contents in the low country BMF compared to mid and up country elevation categories. ...
Production of instant tea, which is used as a colorant and a beverage ingredient, is a growing industry in the world. Refuse tea is industrially identified as Broken Mixed Fannings (BMF) and is a primary raw material for instant tea production due to its cost-effectiveness. This study was carried out to assess the quality variation of BMF obtained from tea estates of different elevation categories and instant black tea powder produced from these BMF types to explore opportunities to produce instant tea types that customers prefer. BMF samples were collected from ten different estates, representing the elevation categories of up (LC), mid (MC) and low (LC) country of Sri Lanka. Total antioxidant activity (TAA), total polyphenol (TPC), caffeine and moisture contents, colour, haze and pH of both BMF and instant tea powder were analysed using standard methods. Though significant differences were not observed among elevation categories for the parameters of colour, pH, contents of moisture, caffeine, TPC and TAA for both BMF and instant tea, there were significant variations in these parameters among estates. TPP content was highest in Halgolla of LC (18.5%) and lowest in Deniyaya of MC (10.1%). There was a significant difference in haze value of up country BMF (38.5 NTU) and the instant tea produced from them (138 NTU), compared to mid and low elevation categories. The highest caffeine contents for both BMF and instant tea were observed from low country estates. In average, TAA content was increased by three-folds and TPC content by two-folds when instant tea powder was produced from BMF. Therefore, the quality variations of instant tea types produced from BMF of different estates of elevation categories revealed the possibility of formulating required quality and healthy products based on customer preference by selecting proper combinations and proportions from known sources of raw materials.
... Different light quality and light intensity have a great influence on the growth of tea trees and the accumulation of flavonoids. Many studies have shown that shading and low-intensity white light treatment had a certain inhibitory effect on the accumulation of catechins and flavonols, which is beneficial to the growth of tea trees and the improvement of tea quality [49][50][51]. In the spring where the light is weak, the accumulation of flavonoids in the tea is relatively low, and the tea quality is higher compared to the summer and autumn when the light is strong [52,53]. ...
Flavonol derivatives are a group of flavonoids benefiting human health. Their abundant presence in tea is associated with astringent taste. To date, mechanism pertaining to the biosynthesis of flavonols in tea plants remains unknown. In this study, we used bioinformatic analysis mining the tea genome and obtained three cDNAs that were annotated to encode flavonol synthases (FLS). Three cDNAs, namely CsFLSa, b, and c, were heterogenously expressed in E. coli to induce recombinant proteins, which were further used to incubate with three substrates, dihydrokampferol (DHK), dihydroquercetin (DHQ), and dihydromyricetin (DHM). The resulting data showed that three rCsFLSs preferred to catalyze (DHK). Overexpression of each cDNA in tobacco led to the increase of kampferol and the reduction of anthocyanins in flowers. Further metabolic profiling of flavan-3-ols in young tea shoots characterized that kaempferol derivatives were the most abundant, followed by quercetin and then myricetin derivatives. Taken together, these data characterized the key step committed to the biosynthesis of flavonols in tea leaves. Moreover, these data enhance understanding the metabolic accumulation relevance between flavonols and other main flavonoids such as flavan-3-ols in tea leaves.
... It is characterized by a reduced amount of photosynthetically active radiations (PAR) and changes in the spectral composition of light (Park and Runkle 2017;Yang F et al. 2018b) (Fig. 2). It not only affects the amount of light received by plants but also alters the plant environmental conditions, such as the temperature of air and ground around the plant, humidity, carbon dioxide (CO 2 ) concentrations, etc., that are essential for plant growth (Song et al. 2012). Low light conditions substantially affect various agronomic traits of plants . ...
Under natural conditions, plants constantly encounter various biotic and abiotic factors, which can potentially restrict plant growth and development and even limit crop productivity. Among various abiotic factors affecting plant photosynthesis, light serves as an important factor that drives carbon metabolism in plants and supports life on earth. The two components of light (light quality and light intensity) greatly affect plant photosynthesis and other plant's morphological, physiological and biochemical parameters. The response of plants to different spectral radiations and intensities differ in various species and also depends on growing conditions. To date, much research has been conducted regarding how different spectral radiations of varying intensity can affect plant growth and development. This review is an effort to briefly summarize the available information on the effects of light components on various plant parameters such as stem and leaf morphology and anatomy, stomatal development, photosynthetic apparatus, pigment composition, reactive oxygen species (ROS) production, antioxidants, and hormone production.
... EGCG is the major tea polyphenol, constituting 12% or more (dry matter) of fresh leaf solids. The quality of green tea is believed to correlate with the catechin levels of its fresh leaves, which decrease with the age of the leaves (Wan et al., 2008;Song et al., 2012;Al-zubaidi, 2015). ...
The level content of the main flavanols in green tea (i.e. epi-structured catechins) in regular commercial green tea bags commonly consumed in the United Kingdom (UK)have been examined using reversed-phasehigh-pressure liquid chromatography (RP-HPLC). Tea bags were purchased from different local supermarkets in the UK and extracted with natural mineral water at temperature 100°C for 9 minutes at the pre-adjusted pH 4.The level of four catechins (Epi-structured)for the fourteen types of green teawere separated and determinedby HPLC analysis,i.e. ()-epigallocatechin (EGC), ()-epicatechin (EC), ()-epigallocatechin-3-gallate (EGCG) and ()-epicatechingallate (ECG). The standard graphs were validated using certified reference catechins supplied by the Laboratory of the Government Chemist (LGC).The levels of total catechins and oxygen radical absorbance capacity (ORAC) values varied from 96.38 to 205.03 mg/g, 1097.30-3421.14Trolox equivalents/g tea bags for fourteen types of green teas respectively.It was evident from the results of this study that there was significant linear and positive correlation (r = 0.932, df = 13, p < 0.05) is found to 05 exist between the total catechins contents and ORACvalues.It couldbe concluded that the developed HPLC method gave reliable results for catechins measurementscoupled to this; the well-known ORAC assay was successfully adapted to measure the antioxidant capacity of the green tea extracts throughout this study. Moreover, the higher the level of catechins the greater is the antioxidant capacity of the tea. However,the differences between the studied brands are owing to production, shelf life and storage conditions.
... The differences were observed to be statistically significant. The researchers stated that the nets used in agricultural production reduce the light intensity (Song et al., 2012;Zhao et al., 2012). This shows that our values are similar with the findings of the researches. ...
The aim of this study is to determine the effects of insect net placed on ventilation openings in greenhouses on temperature, humidity and radiation energy from indoor conditions. In addition, the effects of insect net on the agents used in biological control have been tried to be determined. The study was carried out between
Tea plant (Camellia sect. Thea) is an important cash crop with extensive adaptability in the world. However, complex environmental factors force a large variation of tea quality-related components. Caffeine is essential for the formation of bitter and fresh flavors in tea, and is the main compound of tea that improves human alertness. Continuous strong light stimulation will result in caffeine reduction in tea leaves, but the mechanism is not clear. In this study, the response of tea plant to light intensity was analyzed mainly by multi-omics association, antisense oligodeoxynucleotide (asODN) silencing technique, and in vitro enzyme activity assay. The results revealed multiple strategies for light intensity adaptation in tea plant, among which the regulation of chloroplasts, photosynthesis, porphyrin metabolism, and resistance to oxidative stress were prominent. Caffeine catabolism was enhanced in continuous strong light, which may be a light-adapted strategy due to strict regulation by xanthine dehydrogenase (XDH). asODN silencing and enzymatic activity assays confirmed that CsXDH1 is a protein induced by light intensity to catalyze the substrate xanthine. CsXDH1 asODN silencing resulted in significant up-regulation of both caffeine and theobromine in in vitro enzyme activity assay, but not in vivo. CsXDH1 may act as a coordinator in light intensity adaptation thus disrupting this balance of caffeine catabolism.
Magnesium chelatase catalyzes the insertion of magnesium into protoporphyrin IX, a vital step in chlorophyll biogenesis. The enzyme consists of three subunits, (Magnesium chelatase I subunit, CHLI), (Magnesium chelatase D subunit, CHLD) and (Magnesium chelatase H subunit, CHLH). The CHLI subunit is an ATPase that mediates catalysis. Previous studies on CHLI have mainly focused on model plant species, and its functions in other species have not been well described, especially with regard to leaf coloration and metabolism. In this study, we identified and characterized a CHLI mutant in strawberry species Fragaria pentaphylla. The mutant, noted as p240, exhibits yellow-green leaves and a low chlorophyll (Chl) level. RNA-seq identified a mutation in the 186th amino acid of the CHLI subunit, a base conserved in most photosynthetic organisms. Transient transformation of wild-type CHLI into p240 leaves complemented the mutant phenotype. Further mutants generated from RNA-interference (RNAi) and CRISPR/Cas9 gene editing recapitulated the mutant phenotype. Notably, heterozygous chli mutants accumulated more chlorophyll under low light conditions compared to high light conditions. Metabolite analysis of null mutants under high light conditions revealed substantial changes in both nitrogen and carbon metabolism. Further analysis indicated that mutation in Glu186 of CHLI does not affect its subcellular localization, nor the interaction between CHLI and CHLD. However, intramolecular interactions were impaired, leading to reduced ATPase and magnesium chelatase activity. These findings demonstrate that Glu186 plays a key role in enzyme function, affecting leaf coloration via the formation of the hexameric ring itself, and that manipulation of CHLI may be a means to improve strawberry plant fitness and photosynthetic efficiency under low light conditions.
Haze or tea cream in instant tea significantly affects teabased product manufacturing due to its impact in preparing unclouded tea infusions. The effect of preprocessing temperature of spray drying and cultivar elevation with haze development of instant tea production from Broken Mixed Fannings (BMF) was studied first time by analyzing Total polyphenol (TPC), caffeine content, yield and haze value in instant tea. Significant differences in haze and TPC percentages were observed across elevation categories of upcountry (86.1 NTU &16.33%), mid country (49.6 NTU &13.25%), and low country (29.7 NTU &11.94%) respectively. A strong positive correlation (0.992) was observed between TPC and haze level while a negative correlation showed between Caffeine and haze level (-0.967). However, there were no significant differences for haze, TPC and caffeine contents among tea estates in the same elevation category. The highest yield (27.17%) and lowest haze value (48.75 NTU) of instant tea were reported at the preprocess spray drying temperature of 70 °C when compared with 40, 50, 60, 80 and 90 °C. The method was validated in large-scale production and could be recommended as a proven methodology to reduce haze development and acquire a high yield of instant tea.
(1) Background: beverages based on extracts from Camellia sinensis are popular worldwide. Due to an increasing number of processed teas on the market, there is a need to develop unified classification standards based on chemical analysis. Meanwhile, phytochemical characterizations are mainly performed on tea samples from China (~80%). Hence, data on teas of other provenances is recommended. (2) Methods: in the present investigation, we characterized lyophilised extracts obtained by infusion, maceration and methanolic extraction derived from tea samples from China, Japan, Sri Lanka and Portugal by phytochemistry (catechins, oxyaromatic acids, flavonols, alkaloids and theanine). The real benefits of drinking the tea were analysed based on the bioavailability of the determined phytochemicals. (3) Results: the infusions revealed the highest total phenolic contents (TPC) amounts, while methanolic extracts yielded the lowest. The correlation matrix indicated that the levels of phenolic compounds were similar in the infusions and methanolic samples, while extractions made by maceration were significantly different. The differences could be partially explained by the different amounts of (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG) and gallic acids (GA). The catechin percentages were significantly lower in the macerations, especially the quantity of EGCG decreases by 4- to 5-fold after this process. (4) Conclusions: the results highlight the importance of the processing methodology to obtain “instant tea”; the composition of the extracts obtained with the same methodology is not significantly affected by the provenance of the tea. However, attention should be drawn to the specificities of the Japanese samples (the tea analysed in the present work was of Sencha quality). In contrast, the extraction methodology significantly affects the phytochemical composition, especially concerning the content of polyphenols. As such, our results indicate that instant tea classification based on chemical composition is sensible, but there is a need for a standard extraction methodology, namely concerning the temperature and time of contact of the tea leaves with the extraction solvent.
As the major bitter- and astringent-tasting components in tea leaves, catechins play an essential role in determining flavor characteristics and health benefits of tea products. This study analyzed the circadian rhythm effects on the accumulation pattern of catechins in tender leaves of three tea cultivars, 'Huangkui' (HK), 'Longjing43' (LJ43) and 'Fuding Dabaicha' (FD). There were two major factors involved in the catechin regulation in tea plants: genetic background of the cultivar-specific regulation, and temporal effects of the circadian rhythm. Etiolated leaves of 'HK' contained lower levels of catechins than 'LJ43' and 'FD'. The composition of EGCG in total catechins was significantly higher in 'LJ43' leaves (65%) when compared with that in 'HK' and 'FD' (45%). The accumulation of individual catechins increased during the daytime but decreased overnight, especially over the time period of 22:00−02:00. The correlation analysis between catechins and environmental factors indicated catechin accumulation in tea leaves potentially resulted from a combined regulation of light and temperature. These findings provide new insights into our understanding of circadian rhythm regulation on flavor-important secondary metabolites in tea leaves.
Tea plant (Camellia sinensis) is an important woody economic crop used for processing leaf-type beverages. Numerous studies have shown that light is a necessary environmental condition to control the growth and metabolism of C. sinensis. However, the reference genes of quantitative real time polymerase chain reaction (qRT-PCR) for systematic analysis of light-induced transcription mechanisms are still not available in C. sinensis. In this research, we identified actin family genes that are always used as reference genes with high frequency and without distinction for various expression experiments in C. sinensis. Six pairs of distinctive primers (corresponding to CsACT1, CsACT2, CsACT(3-4), CsACT(5-6), CsACT(7-8), and CsACT(9-10) genes) were designed to evaluate their expression stability in response to light quality (LQ), light intensity (LI), and photoperiod (PD). Simultaneously, six other family members (CsUBC1, CsCLATHRIN1, CsGAPDH, CsTBP, CsTIP41, and CseIF-4α) of C. sinensis commonly used as reference genes were also investigated. The stability rankings of gene expression were calculated by the statistical algorithms of geNorm, BestKeeper, NormFinder, and RefFinder softwares. CsACT(5-6), CsTIP41, and CsACT(3-4) were the most stable genes for light quality (LQ), light intensity (LI), and photoperiod (PD) treatments, respectively. This study provides a basis for the selection of reference genes for future research on the transcription mechanism of light response in C. sinensis. The study on the expression stability of individual members of housekeeping gene family will help to guide the accurate design of detection primers and clarify transcription mechanism in expression experiments.
Crush–tear–curl (CTC) black tea is a popular beverage, owing to its unique taste characteristics and health benefits. However, differences in the taste quality and chemical profiles of CTC black tea from different geographical regions remain unclear. In this study, 28 CTC black tea samples were collected from six geographical regions and analyzed using electronic tongue and ultrahigh performance liquid chromatography-Orbitrap-mass spectroscopy. The e-tongue analysis indicated that each region's CTC black tea has its own relatively prominent taste characteristics: Sri Lanka (more umami and astringent), North India (more umami), China (more sweetness and astringent), South India (moderate umami and sweetness), and Kenya (moderate umami and astringent). Based on multivariate statistical analysis, 78 metabolites were tentatively identified and used as potential markers for CTC black tea of different origins, mainly including amino acids, flavone/flavonol glycosides, and pigments. Different metabolites, which contributed to the taste characteristics of CTC black tea, were clarified by partial least squares regression correlation analysis. Our findings may serve as useful references for future studies on origin traceability and quality characteristic determination of CTC black teas.
Practical Application
This study provides useful references for future studies on the origin traceability and taste characteristic determination of CTC black teas from different geographical regions.
Indigenous communities throughout the globe respond to COVID-19 by their traditional medicinal systems as primary health care. Our lab was part of an international study that discusses the outcomes of a rapid response, preliminary survey during the first phase of the pandemic among social and community contacts in five metropolises heavily affected by the COVID-19 health crisis (Wuhan, Milan, Madrid, New York, and Rio de Janeiro) and in twelve rural areas or countries initially less affected by the pandemic (Appalachia, and South Africa). Primarily, people have relied on teas and spices ("food-medicines") to prevent and mitigate its symptoms. Urban diasporas and rural households seem to have repurposed homemade plant-based remedies that they use on daily basis to treat the flu and other respiratory problems and hence consider among the healthy foods. The most remarkable shift in many areas has been increased in the consumption of ginger and garlic, followed by onion, turmeric, lemon, chamomile, black tea, nettle, chili pepper, and apple. This study serves as a baseline for future systematic ethnobotanical studies countering COVID-19 and other vicious types of viruses. It aims to inspire in-depth research on how use patterns of plant-based foods and beverages, both "traditional" and "new," are changing during and after the COVID-19 pandemic. Our reflections in this study call attention to the importance of ethnobiology, ethnomedicine, and ethno-gastronomy research into domestic health care strategies for improving community health. Some of these economically important plants are suggested to be extensively analyzed experimentally, for active ingredients, phytochemicals, and the precursor of vaccines and probable remedy of SARS including COVID-19.
Tea (Camellia sinensisL.) leaves undergo complex chemical transformations during black tea processing. However, the dynamic chemical changes during tea processing have not been explored in popular cultivars of North East India. In this study, changes in catechins, caffeine, total polyphenol (TP) and formation of theaflavins were examined throughout the different stages of CTC (curl, tear and crush) black tea processing based on UPLC metabolomic analysis along with antioxidant activity for eight cultivarsviz.S.3A/3, TV1, TV7, TV9, TV17, TV22, TV23 and TV25. The results demonstrated that the most prolific changes were observed after complete maceration of tea leaves. The total catechin, (−)-epigallocatechin gallate and (−)-epicatechin gallate levels decreased by 96, 97 and 89%, respectively as the processing progressed from fresh leaves to black tea. The TP level decreased by 26 to 37% throughout the processing path. The caffeine content increased by 18% during processing. The total theaflavin reached the highest level at 20 min of fermentation and then decreased by 13 to 36% at 40 min. Cultivar TV23 and S.3A/3 had a high content of total theaflavin with 17.9 and 16.9 mg g⁻¹, respectively. The antioxidant activity was observed to be decreased by 31% for the black tea as compared to fresh leaves. It is also observed that the total phenolic content exerted a greater effect on antioxidant activity rather than catechins and theaflavins. This study provides an insightful observation of black tea processing which will immensely help in improving the quality of processed tea.
Fresh tea leaves (Camellia sinensis; Chuanxiaoye) used to make tencha tea are a combination of the stem and leaf. Tencha made from the leaf alone is considered a high‐quality tencha beverage with a seaweed‐like aroma, mellow taste, and a green appearance. However, no study has investigated the differences between these two variants. In this study, the effects of stem removal on physicochemical properties and sensory quality of tencha beverage were investigated. The appearance feature, taste, and aroma were evaluated, and the results indicated that stem removal improved the quality of tencha beverages. The water extract, total free amino acids, total catechin, epigallocatechin gallate, caffeine, and chlorophyll were higher in leaf‐only tencha (LOT) than in leaf and stem tencha (LST), whereas the crude fiber and phenol ammonia ratios were lower in LOT than in LST. Principal component analysis and hierarchical clustering analysis further discriminated between the tencha beverages with different stem contents. This study provided a theoretical basis for quality control by adopting a stem–leaf separation process in tencha manufacturing.
Practical Application
This research provides theoretical guidance for improving tencha quality during manufacturing.
Background:
Green, white, and black tea water extracts are rich in phenolic compounds.
Objective:
The changes in phenolic compounds profiles of green, white, and black tea (GT, WT, & BT respectively) water extracts and their respective yogurt were investigated.
Method:
Three types of yogurt with tea water extracts were prepared and the phenolic compounds profiles were analyzed using liquid chromatography mass spectrometry (LC-MS) method.
Results:
The present data found that flavonol glycosides such as kaempferol-3-rutinoside and quercetin-rhamnosylgalactoside or rutinoside were present in WT extract whereas catechin derivatives such as gallocatechin (GC) and epigallocatechin (EGC) were present in GT extract. Moreover, theaflavin-3-O-gallate was observed in BT extract. Many of the catechin and its derivatives detected in the tea extracts were not identified in the tea yogurt samples. However, new phenolic compounds were present in GT-yogurt (i.e. kaempferol-3- rutinoside and quinic acid conjugate) but absent in GT extract.
Conclusion:
GT, WT, & BT extracts could be used to enriched-yogurt with phenolic compounds which may have antioxidant properties.
Supercritical fluid and solvent extraction of catechin from green tea (Camellia sinensis) leaves was studied. Response surface methodology was used to design the experiment and optimize the operating variables (pressure, temperature and dynamic time). The optimum recovery of the extractable crude yield (6.65%), TPC (28.07g/100gGAE), EGCG (263.06mg/100ml), and total catechin (844.25mg/100ml) were obtained at pressure (30Mpa), temperature (47.99 o C and dynamic time(40 minutes) with a co-solvent (50% v/v water :ethanol) and CO 2 flow rates of 1,5 and 1.0ml/ minute respectively. When organic solvent was used, the extractable components were in the range of: total crude extract (2.05-3.57%), TPC (153.22-94.95g/(100gGAE), and TC (285.27mg/100ml) respectively. (With methanol 70 % (v/v), ethanol 50% (v/v), and ethanol 70% (v/v) being the most effective in term of extracts. The result of the extracts obtained by SFE extraction when compared to that of solvent shows that SFE was more effective in the recovery of catechin polyphenols from green tea leaves. By comparing conventional solvent and SFE extraction we were able to identify the abundance of green tea polyphenol from Malaysia which can compete favourably with those obtained from other tea producing countries. The knowledge can be useful to functional food manufacturers. Index Term-Extraction, Supercritical Fluid extraction (SFE), solvent extraction, green tea catechin and functional food.
Alanine contributes to the taste and nutritional quality of tea and is an important member of alanine metabolism catalyzed by alanine aminotransferase (AlaAT, EC 2.6.1.2). However, the molecular mechanism underlying alanine metabolism in tea plants has not been fully elucidated. In this study, an increase in enzyme activity of AlaAT2 was detected in vitro, and the alanine aminotransferase activity was higher level in leaves than that in other tissues of tea plant, while the CsAlaAT2 transcription was high in leaves and root. Using phylogenetic analysis, an alanine aminotransferase gene CsAlaAT2 was identified as a member of group C, which was located in the mitochondrion. Additionally, the molecular mass of CsAlaAT2 protein was found to be approximately 53 kDa by SDS-PAGE and western blotting. The CsAlaAT2 expression level and the alanine content in photosynthetic tissues increased in response to the shade treatment. Furthermore, the involvement of CsAlaAT2 in alanine biosynthesis was confirmed based on transient suppression assays in tea leaves, and the alanine content and CsAlaAT2 transcript level decreased when CsAlaAT2 expression was suppressed in tea leaves. Thus, this study suggests that CsAlaAT2 is essential for the alanine metabolism in tea plants grown and its response to shade.
In this study, ‘Zhongcha108′ (ZC) and its offspring cultivar ‘Zhongming7′ (ZM) were used to investigate the variation in characteristic compounds at different leaf positions. The results showed that there were differences between the two cultivars beyond the leaf position. The concentrations of theanine and caffeine were significantly higher in ZM, whereas more catechins accumulated in ZC. The expression levels of genes related to the theanine, caffeine and catechin pathways were determined by quantitative real time PCR. Compared with ZC, ZM showed higher expression levels of genes involved in theanine biosynthesis and transport, including GOGAT, GS(TS), AlaAT, AspAT, AS and AAP, suggesting that effective biosynthesis and translocation facilitate theanine accumulation in ZM. The caffeine content in ZC was positively correlated with the gene expression of TCS. However, such a correlation was not observed in ZM, which might be related to highly expressed genes involved in caffeine degradation, including CYP1A2, ALN and XO. Furthermore, catechin biosynthesis was regulated by different structural genes in the two cultivars. Higher catechins contents in ZC were related to higher genes expression levels, particularly for PAL, 4CL, F3H, FLS and LAR. A correlation analysis among key genes involved in theanine, caffeine, and catechin biosynthesis also showed consistent results. In ZC, catechins biosynthesis was more active, which inhibited the biosynthesis of nitrogen-rich metabolites, particularly for theanine. The balance of secondary metabolisms in ZM was shifted toward increasing the synthesis of nitrogen-containing compounds, i.e., theanine and caffeine. Taken together, these data reveal different regulatory mechanisms of theanine, caffeine, and catechins within two genetically similar tea cultivars. This work provides an important basis for further research on the characteristic metabolites of tea plants.
The United States (U.S.) consumed over 80 billion servings of tea, approximately 3.8 billion gallons, in the year of 2018. With the vast majority of tea demand being met by importation, the United States became the third largest tea importer worldwide after Russia and Pakistan. As demand for domestically produced tea increases and growers expressing increasing interest in growing and producing tea, tea production became an emerging industry in the United States. Compared to major tea producing countries with centuries of growing history, tea production in the United States is limited and requires research support in many aspect of tea production including selecting suitable cultivars adapted to local climatic conditions. This study evaluated nine tea cultivars, including ‘BL1,’ ‘BL2,’ ‘Black Sea,’ ‘Christine’s Choice,’ ‘Dave’s Fave,’ ‘Large Leaf,’ ‘Small Leaf,’ ‘Sochi,’ and ‘var. assamica,’ for plant growth, leaf morphological characteristics, cold tolerance, and leaf biochemical compositions when grown in Mississippi United States with a subtropical climate. The nine tested cultivars had varying plant growth indices (PGI) and varying degrees of cold tolerance to freezing temperatures in winter, but resumed healthy growth the following spring. ‘BL2’ showed the highest PGI of 104.53 cm by February 2019, which might be helpful toward suppressing weed and early establishment of tea plantation. The nine cultivars also showed varying leaf characteristics in terms of leaf length, width, area, fresh and dry weights, and new shoot weight. There existed a diversity in leaf biochemical composition including soluble solids, carbohydrates, total polyphenols (TP), free amino acids (AA), L-theanine and caffeine among the nine cultivars and among different harvesting seasons of spring, summer, and fall within a certain cultivar. The nine cultivars in this study generally grow well in local environment. All tea samples collected from nine cultivars and three seasons were considered suitable for green tea processing with low TP/AA ratios ranging from 1.72 to 3.71 in this study.
Plants contain a vast array of compounds referred to as secondary metabolites that play no role in primary catabolic or biosynthetic pathways. Many of these metabolites influence important ecological interactions (e.g., deterring herbivores, protection against pathogens, allelopathy, symbiotic associations, seed germination of parasites, or interactions with pollinators). Others provide protection against ultraviolet radiation or high temperatures. We have already discussed some of these roles. In this chapter, we discuss the role of secondary compounds in allelopathic and plant-herbivore interactions. As an example of the metabolic versatility of plants, their responses to xenobiotics will be discussed in the context of phytoremediation. Plant-pathogen interactions are discussed in Chap. 10.1007/978-3-030-29639-1_14.
Caffeine-containing products have been consumed for hundreds of years for their pleasent flavor and stimulating effects. In recent years, caffeine received increasing attention in food and pharmaceutical industries, due to its pharmacological properties which comprise stimulation of the central nervous system, peripheral vasoconstriction, relaxation of the smooth muscle and myocardial stimulation. The aim of this study was to determine the content of caffeine in five types of tea (white, yellow, green, oolong, black) and two types of maté tea (green maté and roasted maté tea). The content of caffeine was determined by using four different methods: extraction with chloroform, micro-method, method with lead-acetate and high performance liquid chromatography method (HPLC-PDA). The antioxidant capacity of teas as well as of the extracted („ raw“ ) caffeine was determined by using two methods: reactions with 2, 2`-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical (ABTS assay) and Ferric reducing antioxidant power (FRAP assay). The content of caffeine has been associated to plant origin and growth conditions, as well as processing conditions. By applying all four methods, the highest content of caffeine was determined in white tea, whereas maté and roasted maté tea were characterised with the lowest content of caffeine. The results of the micro-method and the method with lead-acetate have a good correlation with the results of HPLC method. Micro-method has proven to be the best alternative to the HPLC method. The highest antioxidant capacity was determined in yellow tea, while the lowest was determined in roasted maté tea. In comparison to the antioxidant capacity of teas, the antioxidant capacity of extracted („ raw“ ) caffeine is almost negligible, and does not contribute to the overall antioxidant properties of tea.
Human gammadelta T cells mediate innate immunity to microbes via T cell receptor-dependent recognition of unprocessed antigens with conserved molecular patterns. These nonpeptide alkylamine antigens are shared by tumor cells, bacteria, parasites, and fungi but also by edible plant products such as tea, apples, mushrooms, and wine. Here we show that priming of gammadelta T cells with alkylamine antigens in vitro results in a memory response to these antigens. Such priming results also in a nonmemory response to whole bacteria and to lipopolysaccharide, characterized by IL-12-dependent secretion of IFN-gamma by gammadelta T cells and by gammadelta T cell proliferation. Drinking tea, which contains l-theanine, a precursor of the nonpeptide antigen ethylamine, primed peripheral blood gammadelta T cells to mediate a memory response on reexposure to ethylamine and to secrete IFN-gamma in response to bacteria. This unique combination of innate immune response and immunologic memory shows that gammadelta T cells can function as a bridge between innate and acquired immunity. In addition, these data provide an explanation for the health benefits of tea.
Green tea consumption is reportedly associated with various health-promoting properties. For example, it has been shown to promote fat oxidation in humans at rest and to prevent obesity and improve insulin sensitivity in mice.
We investigated the effects of acute ingestion of green tea extract (GTE) on glucose tolerance and fat oxidation during moderate-intensity exercise in humans.
Two studies were performed, both with a counter-balanced crossover design. In study A, 12 healthy men performed a 30-min cycling exercise at 60% of maximal oxygen consumption (VO2max) before and after supplementation. In study B, 11 healthy men took an oral-glucose-tolerance test before and after supplementation. In the 24-h period before the experimental trials, participants ingested 3 capsules containing either GTE (total: 890 +/- 13 mg polyphenols and 366 +/- 5 mg EGCG) or a corn-flour placebo (total: 1729 +/- 22 mg).
Average fat oxidation rates were 17% higher after ingestion of GTE than after ingestion of placebo (0.41 +/- 0.03 and 0.35 +/- 0.03 g/min, respectively; P < 0.05). Moreover, the contribution of fat oxidation to total energy expenditure was also significantly higher, by a similar percentage, after GTE supplementation. The insulin area under the curve decreased in both the GTE and placebo trials (3612 +/- 301 and 4280 +/- 309 microIU/dL . 120 min, respectively; P < 0.01), and there was a concomitant increase of 13% in insulin sensitivity.
Acute GTE ingestion can increase fat oxidation during moderate-intensity exercise and can improve insulin sensitivity and glucose tolerance in healthy young men.
茶の水耕栽培において, 日射量や昼夜の温度差が品質や生長に与える影響について, 茶中の遊離アミノ酸含量, 葉の光合成速度, 新芽の伸長度および新葉の呼吸速度の観点から検討した.本論文の要点は以下のとおりである.(1) 80%遮光区では, 新芽の葉および茎においてテアニンやアルギニン, グルタミンなどの遊離アミノ酸含量が顕著に増加し, 葉で約4倍～6.5倍, 茎で約15倍～6.5倍の値であった.この増加率は葉においてより顕著であった.また, 根でもテアニンやアルギニン, ヒスチジンなどが増加する傾向を示したが, 葉や茎に比べてわずかであった.いっぽう, 60%および25%遮光区ではどの部位でも遮光による遊離アミノ酸の増加はほとんどみられなかった.(2) カフェイン含量は80%遮光区では新芽の葉で約1.8倍, 茎で約1.5倍増加した.(3) 80%遮光区では, 新芽部分の全遊離アミノ酸含量は無遮光区に比べて約3倍増加した.いっぽう, 60%および25%遮光区では遮光の有無による差はみられなかった.(4) 茶新葉での見かけの最大光合成速度は約85mgCO2dm-2h-1と成葉の約3.5倍であった.また, 新葉での飽和光合成光強度は約800μmol m-2s-1と, これも成葉の約2.7倍であった.このように新葉と成葉では光利用効率に大きな差がみられた.(5) 新芽の伸長は昼夜の温度差が大きいほど促進されることが明らかとなった.また, 昼夜の温度差が茶中の遊離アミノ酸含量に与える影響を検討したところ, 温度差が11℃の場合, 新芽の葉ではテアニンやグルタミンの含量が約2倍増加した.また, 茎でもこれらの遊離アミノ酸含量は1.5倍程度増加していた.(6) 昼夜の温度差を変化させてもカフェイン含量には差はみられなかった.(7) 昼夜の温度差が11℃の場合には, 新芽部分の全遊離アミノ酸含量は温度差5℃および1℃に比べて約1.5倍増加していた.なお, 温度差が5℃と1℃とでは両者の全遊離アミノ酸含量に差はみられなかった.(8) 茶新葉の呼吸速度は夜間温度が高くなるほど増大し, 25℃では15℃の場合の約3倍であった.このように夜温が低いほど茶樹の代謝速度が抑えられ, このことも, 夜温が低いほど新芽の伸長度が大きく, また, 遊離アミノ酸含量も高くなる一因と考えられる.最後に, 本研究を進めるに際し茶樹の提供をいただいた埼玉県茶業試験場岡野信雄部長, 水耕栽培法についてご指導いただいた静岡大学小西茂毅教授, (株) 宇治園中川米秋工場長に深く感謝申し上げます.また, 水耕栽培茶の管理でお世話になった川西春義氏および北電興業 (株) 菅原彰敏氏に感謝致します.
The shading treatment of tea plants for a few weeks before the harvest enriches tea leaves with free amino acids such as theanine and brings the specially flavor-rich quality of green tea. There are difficulties in producing the flavor-rich green tea in the midsummer under the shading treatment because of the excessively high temperature condition. The evaporative cooling treatment by sprinkling water over tea plants intermittently in the daytime dropped temperatures of leaves and the ambient air by 3°C, and further the radiative cooling treatment by opening the shade screen net during the nighttime dropped the temperatures by 2°C. Thus, these passive cooling treatments were demonstrated effectively to drop temperatures of leaves and the ambient air in the summer production of green tea.
A wide consumption of caffeine by almost every human culture on earth is discussed. According to a Caffeine researcher Lawrence Armstrong, Caffeine is a substance of dependence, not a drug and addiction. One real risk of taking caffeine is a small elevation in bone fractures among people drinking four or more cups a day. Caffeine causes some degree of calcium loss, with a possible effect on bone density.
Catechins are the main ingredients of green tea extracts and have been shown to possess versatile biological activities, including antimicrobial. We determined that the catechins inhibit bacterial DNA gyrase by binding to the ATP binding site of the gyrase B subunit. In the group of four tested catechins, epigallocatechin gallate (EGCG) had the highest activity, followed by epicatechin gallate (ECG) and epigallocatechin (EGC). Specific binding to the N-terminal 24 kDa fragment of gyrase B was determined by fluorescence spectroscopy and confirmed using heteronuclear two-dimensional NMR spectroscopy of the EGCG-15N-labeled gyrase B fragment complex. Protein residues affected by binding to EGCG were identified through chemical shift perturbation. Molecular docking calculations suggest that the benzopyran ring of EGCG penetrates deeply into the active site while the galloyl moiety anchors it to the cleft through interactions with its hydroxyl groups, which explains the higher activity of EGCG and ECG.
The N-ethyl carbon of theanine was significantly incorporated into the phloroglucinol nucleus of catechins in tea shoots. This incorporation was controlled by light. Acetate-1-14C was also incorporated into the phloroglucinol nucleus, but most of its activity was randomly distributed in other compounds, and light had no effect. The physiological significance of theanine in catechin biosynthesis in tea plants is discussed.
1. Oxygen is a toxic gas - an introductionto oxygen toxicity and reactive species 2. The chemistry of free radicals and related 'reactive species' 3. Antioxidant defences Endogenous and Diet Derived 4. Cellular responses to oxidative stress: adaptation, damage, repair, senescence and death 5. Measurement of reactive species 6. Reactive species can pose special problems needing special solutions. Some examples. 7. Reactive species can be useful some more examples 8. Reactive species can be poisonous: their role in toxicology 9. Reactive species and disease: fact, fiction or filibuster? 10. Ageing, nutrition, disease, and therapy: A role for antioxidants?
Epigallocatechin (EGC) and gallic acid (GA) were prepared by the degalloylation of an epigallocatechin gallate (EGCG) extract from green tea. EGCG was entirely hydrolyzed using a tannase (from Paecilomyces variotii) at pH 6.0, incubating at 40°C for 30min. The antiradical properties and the reducing power of these samples were assessed using the DPPH and FRAP assays, respectively. This work established a relationship between the antioxidant effects of epigallocatechin gallate and the enzymatic reaction products (epigalocatechin and gallic acid). The enzymatic reaction products showed higher scavenging activity and antioxidant capacity when compared to epigallocatechin gallate.
The polyphenols in various parts of the tea plant used in manufacture of tea products (young leaves, old leaves, and stem) were analyzed by HPLC. The young leaves (apical bud and the two youngest leaves) were found to be richer (2.7-fold) in polyphenols than old leaves (from the tenth to the fifth leaf). Also, the tea polyphenols were found to be higher (1.4-fold) in summer than in spring. Ten different types of commercial tea (manufactured tea), including unfermented, semifermented, and fermented tea, were analyzed for their polyphenol compounds, and it was found that both yields of solids in tea water extracts (TWEs) and the amount of (−)-epigallocatechin 3-gallate (EGCG) in these products varied with different tea leaves and processing methods. Longjing tea (unfermented green tea) contained the highest concentration of EGCG and polyphenols, whereas Assam black tea (most fermented) contained the least. Longjing TWEs showed strong inhibitory effect on DNA synthesis in A-431 tumor cells. We also found that green tea polyphenols (GTPs) and EGCG strongly inhibited tumor cell DNA synthesis and peroxyl-radical generation. The evidence suggests that the strong antioxidative and antiproliferative activities of Longjing TWEs and GTPs are mainly due to the higher contents of tea polyphenols. EGCG (the major component of GTPs) showed strong inhibitory action on the growth of immortalized cells (NIH3T3) and tumor cells (S-180II) but almost no effect on the growth of normal cells (C3H10T1/2). Keywords: Polyphenols; EGCG; antiproliferative effect; antioxidative effect; tea water extracts
BACKGROUND: Kucha (Camellia assamica var. kucha) is a novel wild tea resource grown in China and a tea plant containing a sizable amount of theacrine (1,3,7,9-tetramethyluric acid). High-performance liquid chromatography (HPLC) analysis of purine alkaloids and catechins in young leaves of Kucha has been reported previously. However, the compositions of purine alkaloids and catechins in other parts of the plant remain unknown, and more information about the chemical constituents of Kucha is also necessary for further research and development of this new tea resource.
RESULTS: Using HPLC with diode array detection coupled with electrospray ionisation tandem mass spectrometry (HPLC-DAD/ESI-MS/MS), three purine alkaloids, seven catechins and four non-catechin phenolic compounds were identified or tentatively identified in Kucha. Purine alkaloids and catechins in leaves at different developmental stages, flowers, stems, pericarps and seeds of the plant were also quantified for the first time by the HPLC method, which was fully validated. Recoveries of the quantified compounds ranged from 96.67 to 104.33%.
CONCLUSION: The results showed that the total contents of purine alkaloids and catechins were highest in young leaves of Kucha. Theacrine was detected in all parts of the plant and found to be most abundant in pericarps. Copyright
This paper describes the simultaneous determination of catechins and theaflavins in green and black teas, using reversed-phase high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE). The tea polyphenols analyzed included (+)-catechin, catechin gallate, (−)-epicatechin, epicatechin-3-gallate, epigallocatechin, epigallocatechin-3-gallate, theaflavin, theaflavin-3-monogallate, theaflavin-3′-monogallate and theaflavin-3,3′-gallate. These polyphenols together with six other tea ingredients such as caffeine, adenine, theophylline, quercetin, gallic acid and caffeic acid were separated within 27 min by HPLC and in less than 10 min by CE. The optimal analytical conditions of both chromatographic methods were investigated for the convenience and reliability for routine analysis. Both HPLC and CE were found to be reliable and compatible. The reproducibility of the within-day assay using both methods was generally >90%. The day-to-day variation of retention time was <5% for HPLC, while the variation of migration time for CE was <2%. The analysis time of CE was three-times faster, however it is five-times less sensitive than HPLC, which has detection limits of 0.05 μg/ml and 0.5 μg/ml for catechins and theaflavins, respectively.
A study of a variety of stationary phases and elution conditions for the liquid chromatographic (LC) determination of six biologically active green tea catechins has resulted in the development of two well-defined, reproducible systems for such analyses which overcome limitations of previously described methods. Comparison of six reversed-phase columns indicates that deactivated stationary phases, which utilize ultrapure silica and maximize coverage of the silica support, provide significantly improved separation and chromatographic efficiencies for catechin analyses using LC, compared to conventional monomeric or polymeric C18 columns. Evaluation of elution conditions used for the separations reveals that the presence of acid in the mobile phase (0.05% trifluoroacetic acid) is essential for both the complete resolution of the catechins present in tea and the efficient chromatography of these compounds. The efficacy of one of the developed systems was demonstrated by the quantitative measurement of the six biologically active catechins in aqueous infusions of green tea (Camellia sinensis). Overall precision values for the analyses were within the range 0.3–1% (relative standard deviation).
The effects of climatic conditions on green tea metabolites in three different growing areas of Jeju Island, South Korea, were investigated through global metabolite profiling by (1)H nuclear magnetic resonance (NMR) spectroscopy. Pattern recognition methods, such as principal component analysis (PCA) and orthogonal projection on latent structure-discriminant analysis (OPLS-DA), revealed clear discriminations of green teas from the three different growing areas. Variations of theanine, isoleucine, leucine, valine, alanine, threonine, glutamine, quinic acid, glucose, epicatechin (EC), epigallocatechin (EGC), epigallocatechin-3-gallate (EGCG), and caffeine levels were responsible for the discriminations. Green teas grown in an area with high temperature, long sun exposure time, and high rainfall had higher levels of theanine but lower levels of isoleucine, leucine, valine, alanine, EC, EGC, EGCG, and caffeine than those grown in areas with relatively low temperature, short sun exposure time, and low rainfall. These results indicate that high temperature, long sun exposure, and high preciptation stimulate theanine synthesis in green tea during the spring season. This study highlights how metabolomics coupled with multivariate statistical analysis can illuminate the metabolic characteristics of green tea associated with climatic variables, thereby allowing for the assessment of quality strategy in green tea production.
Light enhanced the growth of tea seedlings but the amount of caffeine produced in light was almost identical to that in the shade, indicating that more synthesis and/or less degradation of caffeine Occur(s) in shaded seedlings. Administering [ N 1-methyl-14C]-caffeine caffeine to tea shoot tips showed that light promotes the degradation of caffeine only slightly.
When tea plants were shaded with black lawn cloth for several days in the field, the accumulations of (—)-epicatechin, (—)-epicatechin-3-gallate, (—)-epigallocatechin and (—)-epigallocatechin-3-gallate decreased in newly developing tea shoots. Radioactive tracer studies showed that the conversions of glucose-U-14C, shikimic acid-G-14C and phenylalanine-U-14C into (—)-epicatechin and (—)-epigallocatechin moieties were depressed by the shade treatment for tea plants but the incorporation of trans -cinnamic acid-3-14C was not affected. The treatment was found to have no significant effect on the activities of phospho-2-keto-3-deoxy-heptonate. aldolase (EC. 4.1.2.15), 3-dehydroquinate synthase (EC. 4.6.1.3), 3-dehydroquinate dehydratase (EC. 4.2.1.10), shikimate dehydrogenase (EC. 1.1.1.25) and trans -cinnamate 4-monooxygenase (EC. 1.14.13.11) in the shoots, whereas the activity of phenylalanine ammonia-lyase (EC. 4.3.1.5) clearly decreased.
Natural and synthetic methylxanthines inhibit insect feeding and are pesticidal at concentrations known to occur in plants. These effects are due primarily to inhibition of phosphodiesterase activity and to an increase in intracellular cyclic adenosine monophosphate. At lower concentrations, methylxanthines are potent synergists of other pesticides known to activate adenylate cyclase in insects. These data suggest that methylxanthines may function as natural insecticides and that phosphodiesterase inhibitors, alone or in combination with other compounds, may be useful in insect control.
A simple, automated test measuring the ferric reducing ability of plasma, the FRAP assay, is presented as a novel method for assessing "antioxidant power." Ferric to ferrous ion reduction at low pH causes a colored ferrous-tripyridyltriazine complex to form. FRAP values are obtained by comparing the absorbance change at 593 nm in test reaction mixtures with those containing ferrous ions in known concentration. Absorbance changes are linear over a wide concentration range with antioxidant mixtures, including plasma, and with solutions containing one antioxidant in purified form. There is no apparent interaction between antioxidants. Measured stoichiometric factors of Trolox, alpha-tocopherol, ascorbic acid, and uric acid are all 2.0; that of bilirubin is 4.0. Activity of albumin is very low. Within- and between-run CVs are <1.0 and <3.0%, respectively, at 100-1000 micromol/liter. FRAP values of fresh plasma of healthy Chinese adults: 612-1634 micromol/liter (mean, 1017; SD, 206; n = 141). The FRAP assay is inexpensive, reagents are simple to prepare, results are highly reproducible, and the procedure is straightforward and speedy. The FRAP assay offers a putative index of antioxidant, or reducing, potential of biological fluids within the technological reach of every laboratory and researcher interested in oxidative stress and its effects.
A method for measuring the antioxidant capacity and/or the amount of a specific antioxidant in a sample, which comprises: a) at least two samples (A) and (B) to be assayed in parallel; b) addition of an antioxidant deactivator to sample (A) which selectively deactivates the antioxidant ability of an antioxidant in the sample; c) addition of a redox indicator to both samples (A) and (B), the indicator being capable of indicating the antioxidant capacity of each sample absorbance of electromagnetic radiation; d) measurement of the change in absorbance of electromagnetic radiation of the indicator in each sample at a given time interval, from the time when the redox indicator was added to or mixed with the samples or immediately prior to this addition or mixing until a given time after the redox indicator was added; e) determining the antioxidant capacity of the sample and/or the specific antioxidant in the sample, by relating the change in absorbance of electromagnetic radiation of step (d) to the absorbance value of a standard solution run under the same conditions or to molar absorptivity value. US6177260; US6177260 B1; US6177260B1; US6,177,260; US 6,177,260 B1; 6177260; Application No. 08/893,519
A highly specific and sensitive diazotized sulfanilamide reagent is synthesized for determination of tea catechins. The reagent is employed both as spray reagent for selective visualization of tea catechins on two-dimensional paper chromatograms (sensitivity <1 microg of d-(+)-catechin) and for their spectrophotometric quantification in the crude extracts of tea polyphenols isolated from fresh or dried tea shoots. The formation of yellow color (lambda(max) = 425 nm) between catechins and diazotized sulfanilamide was investigated and made the basis of a simple and sensitive spectrophotometric method for estimation of the total and individual catechins in different tea cultivars. At 425 nm, the absorbance was linear (r = 0.999) over the (0.4-8.0 microg/mL) concentration range of d-(+)-catechin.
Current interest in the role of functional foods in weight control has focused on plant ingredients capable of interfering with the sympathoadrenal system.
We investigated whether a green tea extract, by virtue of its high content of caffeine and catechin polyphenols, could increase 24-h energy expenditure (EE) and fat oxidation in humans.
Twenty-four-hour EE, the respiratory quotient (RQ), and the urinary excretion of nitrogen and catecholamines were measured in a respiratory chamber in 10 healthy men. On 3 separate occasions, subjects were randomly assigned among 3 treatments: green tea extract (50 mg caffeine and 90 mg epigallocatechin gallate), caffeine (50 mg), and placebo, which they ingested at breakfast, lunch, and dinner.
Relative to placebo, treatment with the green tea extract resulted in a significant increase in 24-h EE (4%; P < 0.01) and a significant decrease in 24-h RQ (from 0.88 to 0.85; P < 0.001) without any change in urinary nitrogen. Twenty-four-hour urinary norepinephrine excretion was higher during treatment with the green tea extract than with the placebo (40%, P < 0.05). Treatment with caffeine in amounts equivalent to those found in the green tea extract had no effect on EE and RQ nor on urinary nitrogen or catecholamines.
Green tea has thermogenic properties and promotes fat oxidation beyond that explained by its caffeine content per se. The green tea extract may play a role in the control of body composition via sympathetic activation of thermogenesis, fat oxidation, or both.
Several methods have been developed to measure the total antioxidant capacity of a biological sample. The use of peroxyl or hydroxyl radicals as pro-oxidants in the oxygen radical absorbance capacity (ORAC) assay makes it different and unique from the assays that involve oxidants that are not necessarily pro-oxidants. An improvement in quantitation is achieved in the ORAC assay by taking the reaction between substrate and free radicals to completion and using an area-under-curve technique for quantitation compared to the assays that measure a lag phase. The interpretation of the changes in plasma or serum antioxidant capacity becomes complicated by the different methods used in detecting these changes. The interpretation also depends upon the conditions under which the antioxidant capacity is determined because the measurement reflects outcomes in a dynamic system. An increased antioxidant capacity in plasma or serum may not necessarily be a desirable condition if it reflects a response to increased oxidative stress. Similarly, a decrease in plasma or serum antioxidant capacity may not necessarily be an undesirable condition if the measurement reflects decreased production of reactive species. Because of these complications, no single measurement of antioxidant status is going to be sufficient, but a "battery" of measurements, many of which will be described in Forum articles, will be necessary to adequately assess oxidative stress in biological systems.
There is growing interest in the potential health benefits of tea, including the antimutagenic properties. Four varieties of white tea, which represent the least processed form of tea, were shown to have marked antimutagenic activity in the Salmonella assay, particularly in the presence of S9. The most active of these teas, Exotica China white tea, was significantly more effective than Premium green tea (Dragonwell special grade) against 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and four other heterocyclic amine mutagens, namely 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2). Mechanism studies were performed using rat liver S9 in assays for methoxyresorufin O-demethylase (MROD), a marker for the enzyme cytochrome P4501A2 that activates heterocyclic amines, as well as Salmonella assays with the direct-acting mutagen 2-hydroxyamino-3-methylimidazo[4,5-f]quinoline (N-hydroxy-IQ). White tea at low concentrations in the assay inhibited MROD activity, and attenuated the mutagenic activity of N-hydroxy-IQ in the absence of S9. Nine of the major constituents found in green tea also were detected in white tea, including high levels of epigallocatechin-3-gallate (EGCG) and several other polyphenols. When these major constituents were mixed to produce "artificial" teas, according to their relative levels in white and green teas, the complete tea exhibited higher antimutagenic potency compared with the corresponding artificial tea. The results suggest that the greater inhibitory potency of white versus green tea in the Salmonella assay might be related to the relative levels of the nine major constituents, perhaps acting synergistically with other (minor) constituents, to inhibit mutagen activation as well as "scavenging" the reactive intermediate(s).
Levels of total phenol, catechins, and caffeine in teas commonly consumed in the United Kingdom have been determined using reversed phase high-performance liquid chromatography. Tea bags or tea leaves were purchased from local supermarkets and extracted in boiling water for 5 min. The resulting data showed considerable variability in both total phenols [80.5-134.9 mg/g of dry matter (DM) in black teas and 87-106.2 mg/g of DM in green teas] and catechins (5.6-47.5, 51.5-84.3, and 8.5-13.9 mg/g of DM in black, green, and fruit teas, respectively); this was most probably a result of differing agronomic conditions, leaf age, and storage during and after transport, as well as the degree of fermentation. Caffeine contents of black teas (22-28 mg/g of DM) were significantly higher than in less fermented green teas (11-20 mg/g of DM). The relative concentration of the five major tea catechins ranked EGCG > ECG > EC > EGC > C. The estimated U.K. dietary intakes of total tea catechins, calculated on the basis of an average tea consumption of three cups of tea (200 mL cup, 1% tea leaves w/v), were 61.5, 92.7, and 405.5 mg/day from fruit teas, black teas, and green teas, respectively. The coefficients of variation were 19.4, 88.6, and 17.3%, respectively, indicating the wide variation in these intakes. The calculated caffeine intake ranged between 92 and 146 mg/day. In addition, many individuals will consume much larger quantities of tea, of various strengths (as determined by the brewing conditions employed). This broad spread of U.K. daily intakes further emphasizes the need for additional research to relate intake and effect in various population groups.
Antioxidant compounds in green tea may be able to protect against skin carcinogenesis and it is of interest to investigate the mechanisms involved. A study was therefore conducted to determine whether the isolated green tea polyphenol (-)-epigallocatechin gallate (EGCG) could prevent ultraviolet radiation (UVR)-induced DNA damage in cultured human cells. This work was then extended to investigate whether drinking green tea could afford any UVR protection to human peripheral blood cells collected after tea ingestion.
The alkaline comet assay was used to compare the DNA damage induced by UVR in cultured human cells with and without the presence of EGCG. The same assay technique was then employed to assess UVR-induced DNA damage in peripheral leucocytes isolated from 10 adult human volunteers before and after drinking 540 ml of green tea.
Initial trials found that EGCG afforded concentration-dependent photoprotection to cultured human cells with a maximal activity at a culture concentration of 250 microM. The cells types tested (lung fibroblasts, skin fibroblasts and epidermal keratinocytes) demonstrated varying susceptibility to the UVR insult provided. The in vivo trials of green tea also demonstrated a photoprotective effect, with samples of peripheral blood cells taken after green tea consumption showing lower levels of DNA damage than those taken prior to ingestion when exposed to 12 min ultraviolet A (UVA) radiation.
The studies showed that green tea and/or some constituents can offer some protection against UV-induced DNA damage in human cell cultures and also in human peripheral blood samples taken post-tea ingestion.
(-)-Epigallocatechin-3-gallate (EGCG), a major polyphenol of green tea, undergoes substantial biotransformation to species that includes the methylated compounds. Recent studies have demonstrated that the methylated EGCG has many biological activities. In this study, we have investigated the composition of the three O-methylated EGCG derivatives, (-)-epigallocatechin-3-O-(3-O-methyl)gallate (3' '-Me-EGCG), (-)-epigallocatechin-3-O-(4-O-methyl)gallate (4' '-Me-EGCG) and (-)-4'-methyl epigallocatechin-3-O-(4-O-methyl)gallate (4',4' '-di-Me-EGCG) in tea leaves which were picked from various species and at various seasons, ages of leaves, locations, and fermentation levels. Higher levels of 3' '-Me-EGCG and 4' '-Me-EGCG were detected in Chinshin-Kanzai (a species of Camellia sinensis) cultivated in the mountain area of Sansia, Taipei County, Taiwan. Also, these O-methylated EGCG levels were found to be higher in autumn and winter than in spring and summer. The young leaves were found to be richer in the O-methylated compounds than old leaves and the amount of O-methylated EGCG was higher in unfermented longjin green tea than in semifermented oolong tea. However, the fermented black tea and puerh tea did not contain these compounds. 4',4' '-diMe-EGCG could not be detected in either fresh tea leaves or commercial tea leaves. We also found that 3' '-Me-EGCG has a higher inhibitory effect on the nitric oxide generation and inducible nitric oxide synthase (iNOS) expression as compared with EGCG, while 4' '-Me-EGCG and 4',4' '-di-Me-EGCG were less effective.
L-Theanine is an amino acid contained in green tea leaves which is known to block the binding of L-glutamic acid to glutamate receptors in the brain. Because the characteristics of L-Theanine suggest that it may influence psychological and physiological states under stress, the present study examined these possible effects in a laboratory setting using a mental arithmetic task as an acute stressor. Twelve participants underwent four separate trials: one in which they took L-Theanine at the start of an experimental procedure, one in which they took L-Theanine midway, and two control trials in which they either took a placebo or nothing. The experimental sessions were performed by double-blind, and the order of them was counterbalanced. The results showed that L-Theanine intake resulted in a reduction in the heart rate (HR) and salivary immunoglobulin A (s-IgA) responses to an acute stress task relative to the placebo control condition. Moreover, analyses of heart rate variability indicated that the reductions in HR and s-IgA were likely attributable to an attenuation of sympathetic nervous activation. Thus, it was suggested that the oral intake of L-Theanine could cause anti-stress effects via the inhibition of cortical neuron excitation.
Cooperative Extension Service CTAHR (College of Tropical Agriculture and Human Resources
- F Zee
- D Sato
- L Keith
- P Follett
- R T Hamasaki
Zee, F., Sato, D., Keith, L., Follett, P., & Hamasaki, R. T. (2003). Small-scale tea growing
and processing in Hawaii. New Plants for Hawaii. (Vol. 9). Cooperative Extension
Service CTAHR (College of Tropical Agriculture and Human Resources,
University of Hawaii). Available from http://www.ctahr.hawaii.edu/oc/
freepubs/pdf/NPH-9.pdf. Accessed 07.02.12.
Chemistry and applications of green tea
- T Yamamoto
- L R Juneja
- D C Chu
- M Kim
Yamamoto, T., Juneja, L. R., Chu, D. C., & Kim, M. (1997). Chemistry and applications of
green tea. New York: CRC Press.
Tea Sutra or Cha Jing
- L Yu
Yu, L. Tea Sutra or Cha Jing, China, 780 BC.
Introduction and translation of Lu Yu's Tea Sutra (The Classic of Tea
- F R Carpenter
Carpenter, F. R. (1974). Introduction and translation of Lu Yu's Tea Sutra (The Classic of
Tea) (1st ed.). Boston, MA, USA: Little, Brown and Company.
- A B Kamath
- L Wang
- H Das
- L Li
- V N Reinhold
- Bukowski
Kamath, A. B., Wang, L., Das, H., Li, L., Reinhold, V. N., & Bukowski, J. F. (2003).