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Content of potentially anticarcinogenic flavonoids of 28 vegetables and 9 fruits commonly consumed in The Netherlands
Abstract
The content of the potentially anticarcinogenic flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin of 28 vegetables and 9 fruits was determined by RP-HPLC with UV detection. Fresh foods were purchased in a supermarket, agrocery, and a street market and combined to composites. Processed foods were purchased additionally. Sampling was carried out in spring, summer, winter, and spring of the following year. Quercetin levels in the edible parts of most vegetables were generally below 10 mg/kg except for onions (284-486 mg/kg), kale (110 mg/kg), broccoli (30 mg/kg), French beans (32-45 mg/kg), and slicing beans (28-30 mg/kg). Kaempferol could only be detected in kale (211 mg/kg), endive (15-91 mg/kg), leek (11-56 mg/kg), and turnip tops (31-64 mg/kg). In most fruits the quercetin content averaged 15 mg/kg, except for different apple varieties in which 21-72 mg/kg was found. The content of myricetin, luteolin, and apigenin was below the limit of detection (
... Kaempferol is a flavonol that has been shown to have anti-diabetic, pancreatic β-cell protecting, and anti-inflammatory effects in vitro and in vivo [25]. Both Kfo lines accumulate kaempferol at levels higher than other vegetables and fruits, apart from capers [16,[26][27][28][29][30]. The third line, naringenin chalcone overproducer (Nco) accumulates glycosides of naringenin chalcone, a compound not previously reported in lettuce, and which has been shown to have anti-inflammatory, anti-allergic, and anti-obesity effects [16,[31][32][33]. ...
... The leaves were stored at −80 • C, lyophilized and ground to a powder. An acid hydrolysis procedure based on Hertog et al. (1992) [26] and as described in Gurdon et al. (2019) [16] was performed to convert glycosylated flavonoids into respective flavonoid aglycones. In summary, 50 mg of leaf powder was added to a plastic tube, to which 4 mL of solvent (62.5 methanol:32.5 water and 2 g/L tert-butylhydroquinone) was added. ...
... The leaves were stored at −80 • C, lyophilized and ground to a powder. An acid hydrolysis procedure based on Hertog et al. (1992) [26] and as described in Gurdon et al. (2019) [16] was performed to convert glycosylated flavonoids into respective flavonoid aglycones. In summary, 50 mg of leaf powder was added to a plastic tube, to which 4 mL of solvent (62.5 methanol:32.5 water and 2 g/L tert-butylhydroquinone) was added. ...
Flavonoids are antioxidant phytochemicals that confer a beneficial effect on human health. We have previously developed and characterized eight lettuce (Latuca sativa L.) lines that accumulated high levels of diverse flavonoids and their precursors in controlled environment conditions. Three Rutgers Scarlet lettuce (RSL) lines selected in tissue culture for deep-red color (RSL-NAR, RSL-NBR, RSL-NFR) accumulate anthocyanins and quercetin, three lines identified in a chemically mutagenized red lettuce population accumulate kaempferol (KfoA and KfoB) or naringenin chalcone (Nco), and two lines that were spontaneous green mutants derived from the red line RSL-NAR (GSL, GSL-DG) accumulate quercetin. These eight lines were field-grown in the Salinas Valley of California for four years together with seven control accessions of varying colors (light green, dark green, red, and dark red). At market maturity, a substantial variation in plant composition was observed, but the three RSL lines consistently accumulated high levels of cyanidin, GSL and GSL-DG accumulated the highest levels of quercetin, KfoA and KfoB accumulated kaempferol, and Nco amassed naringenin chalcone, confirming that these mutant lines produce high levels of beneficial phytochemicals under field conditions. Mutant lines and control accessions were also assessed for their biomass production (plant weight, height, and width), overall content of pigments (leaf chlorophyll and anthocyanins), resistance to diseases (downy mildew, lettuce drop, and Impatiens necrotic spot virus), postharvest quality of processed tissue (deterioration and enzymatic discoloration), and composition of 23 mineral elements. All but one mutant line had a fresh plant weight at harvest comparable to commercial leaf cultivars; only Nco plants were significantly (p < 0.05) smaller. Therefore, except for Nco, the new, flavonoid hyperaccumulating lines can be considered for field cultivation.
... Полифенолы и флавоноиды-одни из самых важных биологически активных соединений в овощах и фруктах, обеспечивающих положительное действие на здоровье человека [4]. Из 28 овощей и 9 видов фруктов лук занимает первое место по концентрации кверцетина [34] среди сельскохозяйственных культур [35]. ...
... Интервал концентрации кверцетина в луковицах 85 сортов лука репчатого (55 желтых, 3-розовых, 6 красных и 11 белых) также оказался велик: от 0.2 до 286.0 мг/кг сырой массы [52]. Другие исследователи отмечают интервал концентраций от 18 до 1495 мг кверцетина/кг [53,42,52,34]. Результаты показывают, что белые луки содержат следы кверцетина, а наибольший уровень кверцетина характерен для красных сортов. ...
Production and utilization of Allium cepa is the basis of nutritional value and the human health maintainance. The review discusses the main onion biologically active compounds, determining the biological activity of this vegetable, peculiarities of antioxidant and carbohydrate distribution between inner and outer scales, changes in the content and distribution of biologically active compounds and chemical elements in conditions of various abiotic stresses: high temperature, drought, flooding and heavy metal loading. Factors affecting onion pungency and natural antioxidant distribution are included. Special attention is payed to sulphur derivative alkenyl cysteine sulphoxides, and polyphenols and flavonoids, sterols, fructoolygosaccharides, organic acids, amino acids, and minerals. Onion selection on tolerance to the unfavorable environmental factors is discussed. The presented data may be the basis for the direct production of Allium cepa with high yield and valuable nutritional characteristics.
... The content of flavonols present in broccoli, which occur as quercetin and kaempferol O-glycosides, was determined after their acid hydrolysis to quercetin and kaempferol. Extraction and acid hydrolysis of flavonol glycosides were performed as described in the literature with minor modifications (HERTOG et al. 1992;CROZIER et al. 1997). Extracts were prepared as follows: 40 mL of 62.5 % aqueous methanol, containing TBHQ (2 g L -1 ), were added to 0.500 g of freeze-dried sample material and the mixture was sonicated for 20 min. ...
... The content of flavonoids in broccoli depends strongly on cultivar (HERTOG et al. 1992;PRIOR and CAO 2000;VALLEJO et al. 2002;NAIDU 2003). However, BOROWSKI et al. (2008) reported also high variability within the same variety cultivated in the same agricultural and climatic conditions. ...
Postharvest handling of vegetable crops, including storage, may affect the level of bioactive compounds present in plants. Two-year study on the influence of temperature during short-term storage (6 and 24 h) at room temperature and cold-storage (one week) on the content of quercetin, kaempferol and vitamin C in broccoli heads were performed. General Linear Model (GLM) and cluster analysis (CA) were applied to evaluate the effect of time and temperature of storage on the content of tested compounds. It was found that quercetin and kaempferol were stable and no losses of these compounds were observed during storage at room temperature. Vitamin C content significantly decreased under these conditions, whereas cold-storage had no significant influence on the content of this compound in comparison to fresh broccoli. It was also found that the increase of room temperature of storage caused the increase in quercetin and kaempferol contents and higher losses of vitamin C. The drop of cold temperature of storage may also cause decrease in flavonoid content in broccoli. The results demonstrate the importance of storage temperature for the content of vitamin C and flavonoids in broccoli.
... They are also important sources of vitamins like β-carotene, ascorbic acid, riboflavin and folic acid, minerals like Cu, Zn, Mn, Fe, Ca, and P, fibre and antioxidants. Dietary antioxidants reduce the risk of cardiovascular disease (Hertog et al., 1997) [9] , diabetes (Montonen et. al., 2004) [10] , cancer (Ekstrom et al., 2000) [11] and neurodegenerative diseases (Gilgunsherki et al., 2004) [12] . ...
... They are also important sources of vitamins like β-carotene, ascorbic acid, riboflavin and folic acid, minerals like Cu, Zn, Mn, Fe, Ca, and P, fibre and antioxidants. Dietary antioxidants reduce the risk of cardiovascular disease (Hertog et al., 1997) [9] , diabetes (Montonen et. al., 2004) [10] , cancer (Ekstrom et al., 2000) [11] and neurodegenerative diseases (Gilgunsherki et al., 2004) [12] . ...
... The oldest crop that has been farmed and is frequently used in traditional and ethnoscientific medicine to cure a variety of diseases is allium cepa (Ashwini and Sathishkumar, 2014) [4] . Onion is used as an anti-helminthic (Hertog et al., 1992) [15] , hypoglycemic (Oginmodede et al., 2012; Akash et al., 2014) [3] , anti-inflammatory, untirheumatic, antispazmolitic, diuretic, anti-thrombotic, antiseptic (Goodarzi et al., 2013;Kirilov et al., 2014), antiasthmatic, and hypocholesterolemic remedy (Pineda, de la Calzada, 2013) [14] . ...
... The oldest crop that has been farmed and is frequently used in traditional and ethnoscientific medicine to cure a variety of diseases is allium cepa (Ashwini and Sathishkumar, 2014) [4] . Onion is used as an anti-helminthic (Hertog et al., 1992) [15] , hypoglycemic (Oginmodede et al., 2012; Akash et al., 2014) [3] , anti-inflammatory, untirheumatic, antispazmolitic, diuretic, anti-thrombotic, antiseptic (Goodarzi et al., 2013;Kirilov et al., 2014), antiasthmatic, and hypocholesterolemic remedy (Pineda, de la Calzada, 2013) [14] . ...
The indigenous tribes of NorthEastern India have long engaged in the practice of rearing Eri silkworms and making Eri silk fabric. The state of Assam, in particular, is widely recognized for its significant contribution to the nation's production of raw silk. The state's marginal farmers encounter several obstacles throughout the fabric-making process and may not receive the results they were hoping for. Since Assam is one of the most biologically diverse states in the country, the current shift in the fashion and textile industries toward sustainability and eco-friendliness can have a significant impact on the creation of natural dye from a variety of natural resources. In order to determine the color implications for Eri silk yarn, the current study focuses on extracting natural dye from available floral samples from the Nagaon district.
... To determine the bound quercetin content in kitchen onion, a method of extraction in 62.5% ethanol and 6 M HCl was employed, followed by quantification using an HPLC instrument according to the method described by Hertog et al. (1992) [23]. The results were calculated in mg kg −1 of fresh weight of the onion. ...
... To determine the bound quercetin content in kitchen onion, a method of extraction in 62.5% ethanol and 6 M HCl was employed, followed by quantification using an HPLC instrument according to the method described by Hertog et al. (1992) [23]. The results were calculated in mg kg −1 of fresh weight of the onion. ...
This study investigates the impact of nitrogen (N), sulfur (S), and iron (Fe) fertilization on secondary metabolites, particularly quercetin and its forms, in onion bulbs (Allium cepa L.). Field experiments over two years examined four onion varieties with red, yellow, and white colors of bulbs: Kamal, Robin, Pueblo, and Mundo. The parameters investigated included the yield, dry matter content, and average onion weight. The phenolic and flavonoid contents were also analyzed. The free quercetin, bound quercetin, and total quercetin contents were determined using the HPLC method. The results demonstrated notable increases in yield following the application of nitrogen (NH⁴⁺) and sulfur (SO4²⁻) fertilizers. Incorporating iron (Fe²⁺) alongside these fertilizers did not yield a significant impact compared to N+S variant. The phenolic and flavonoid content varied with fertilization, while the quercetin content did not yield statistically significant results. Overall, the study highlights the complex relationship between fertilization practices and secondary metabolite production in onions, emphasizing the need for sustainable intensification in modern agriculture.
... As fontes alimentares de flavonóides são analisadas principalmente em relação a três flavonóis, quercetina, miricetina e kaempferol, e duas flavonas, apigenina e luteolina [18][19][20][21][22][23] . Estes são também os flavonóides mais investigados em estudos sobre compostos anticarcinogênicos. ...
... A hidrólise das diversas formas de glicosídeos para liberar as agliconas oferece um método mais prático, porém, pode provocar a degração dos flavonóides. Glicosídeos são hidrolisados usando-se normalmente HCl em metanol aquoso 18,19,21 . A hidrólise dos glicosídeos requer concentrações relativamente altas de ácidos minerais (1-2M), em condições de refluxo, numa mistura de metanol e água (50:50, v/v) 21 . ...
O objetivo deste trabalho foi otimizar a metodologia analítica para determinação de flavonóis e flavonas em hortaliças. A hidrólise foi otimizada utilizando-se Delineamento Composto Central Rotacional (DCCR) para investigar os efeitos da concentração de HCl e do tempo de hidrólise. Essa etapa foi realizada simultaneamente com a extração por metanol aquoso 50%, em refluxo a 90ºC. Foi utilizado cromatógrafo líquido Waters com coluna Nova-Pak C18 e detector de arranjo de diodos. Os compostos estudados foram miricetina (M), quercetina (Q), kaempferol (K), luteolina (L) e apigenina (A). As condições ótimas encontradas para hidrólise de cada hortaliça foram: 1,0M HCl/6 horas para espinafre e couve, 1,6M HCl/5 horas para rúcula, 1,2M HCl/2 horas para alface, 1,7M HCl/4,3 horas para salsa e 0,8M HCl/2,5 horas para cebola. O melhor gradiente para separação (CLAE) dos flavonóides das hortaliças em estudo foi constituído de metanol:água (acidificados com 0,3% de ácido fórmico) 20:80, chegando a 45:55 em 5 minutos, 48:52 em 17 minutos e voltando a 20:80 em 20 minutos. As curvas analíticas apresentaram coeficientes de correlação maiores que 0,99. Os limites de detecção foram de 0,5, 0,4, 0,5, 0,6 e 1,0μg/mL, respectivamente, para M, Q, L, K e A.
... Reports of the human health benefits of dietary antioxidants have encouraged researchers to examine factors that influence the content of phytochemical antioxidants in fruit and vegetables (Farnham et al., 1999;Goldman et al., 1999;Grusak et al., 1999;Kochian and Garvin,1999). Foods such as apples, onions and tea, contribute significant quantities of flavonoid antioxidants to the diet (Hertog et al., 1993). Other foods such as blueberries, although not consumed in large volumes, have a high antioxidant capacity due to their high content of both flavonoid and nonflavonoid antioxidants Prior et al., 1998;Wang et al., 1996). ...
The antioxidant properties of blueberries have been examined only in ripe fruit, although fruit of different maturities are used in processed food products. In this study, highbush blueberry cultivars Bergitta, Bluegold, and Nelson highbush blueberry fruit at different stages of ripeness were examined to characterize differences in oxygen radical absorbing capacity (ORAC) and the phenolic components responsible for ORAC. Underripe fruit at different stages of maturity were also stored at 20 °C for up to 8 days to assess changes in ORAC and phenolic content. Anthocyanin content was substantially higher in fruit of more advanced stages of ripeness. In contrast, the phenolic content and ORAC were lower in the riper fruit. Anthocyanins continued to form during storage, although rate of pigment formation declined after about 4 days. Less anthocyanin pigment was formed in the less ripe fruit. After 8 days of storage, the anthocyanin content of fruit harvested 5% to 50% or 50% to 95% blue exceeded that of ripe fruit. Up to 60% of the total phenolic content could be accounted for by anthocyanins. ORAC was positively correlated with total phenolic content ( R ² = 0.78), but not with anthocyanin content.
... Certain sections of onion waste are high in flavonoids, the richest being onion skin, where quercetin and its glycosides are the most abundant antioxidant and radical scavenging compounds [8]. In a study of 28 vegetables and 9 fruits, onions had the greatest quercetin content [9]. Specific sulfur-containing compounds and flavonoids are related to a variety of pharmacological activities, including tumour and microbial cell growth suppression, cancer risk reduction, free radical scavenging, and cardiovascular disease prevention [10]. ...
Natural antioxidants have gained interest in recent years as a result of their ability to reduce auto oxidation of fats, oils and fat containing food products by replacing synthetic antioxidants. Yellow and red onion peels were chosen as a natural antioxidant source in our study. In addition, the storage stability, TBA, antimicrobial and organoleptic of beef burgers with yellow or red onion peels or extracts were compared to BHT under refrigerated storage at 4±1°C for 15 days. Also cooking measurements (cooking loss, cooking yield, shrinkage and moisture retention) were compared to BHT. The major components in red onion peels were quercetin 11290.09 µg/g and 1761.31 µg/g in yellow onion peels, according to the findings. The results showed that increasing the amount of onion peels enhanced total phenolic, total flavonoids, and antioxidant activities in burgers. Burgers made with onion peel extracts had the highest levels of total phenol and total flavonoids.The cooking yield and moisture retention of beef burgers using onion peels were both improved. The control burger had the most cooking loss, followed by the BHT prepared burger. As yellow or red onion peels and their extract were put to beef burgers, the pH of the beef was much lower when compared to the control. In the sensory acceptance test, there were no significant differences in color, odor, taste, appearance, and overall acceptability of beef burgers prepared with red and yellow onion peel powder and extracts at zero time, while slightly lower or similar judging scores in all organoleptic characteristics were observed in the tested beef burger samples and control sample during storage periods of two weeks. In addition, yellow or red onion peels, as well as their extract, may have antibacterial properties.
... Капуста имеет более высокую концентрацию кверцетина, чем другие овощи [14,15]. Она является хорошим источником витаминаС (107мг/100г) и каротиноидов (2,7мг/100г) [16]. Эффективным методом, позволяющим определять их в растительных пробах является высокоэффективная жидкостная хроматография -универсальный аналитический метод разделения и анализа сложных смесей. ...
Во многих странах капуста кале быстро завоевывает популярность, так как кроме ее полезных свойств она еще и холодостойкая культура. Содержание витаминов в ней в несколько раз превышает суточную норму. Это объясняет такие мощные антиоксидантные свойства данного листового овоща. В состав капусты кале так же входит множество минералов, она наиболее богата она кальцием, магнием, фосфором, марганцем, медью и железом. Она обладает уникальным биохимическим составом с большим количеством витаминов, флаваноидов, каротиноидов и минеральных элементов и поэтому является очень полезной овощной культурой. Одна порция капусты кале обеспечивает более 100% рекомендуемой суточной нормы потребления витамина А и более 40% витамина С. Эффективным методом, позволяющим определять витамины и флаваноиды в растительных пробах является высокоэффективная жидкостная хроматография - универсальный аналитический метод разделения и анализа сложных смесей. В настоящее время заметно возрос интерес к содержанию кверцетина и других флавоноидов в различных объектах, что связано с их высокой антиоксидантной, антимутагенной и антиканцерогенной активностью, а также рядом других полезных свойств, которыми обладают эти соединения. Исследования позволили выявить наиболее адаптированные к каждой из технологий гибриды по накоплению в листьях капусты кале кварцетина, витамина А, витамина С, сухих веществ и питательных элементов при выращивании на различных типах гидропоники. По результатам исследований гибрид Dwart green curlet F1 рекомендован на аквапонике, а гибриды Scarlet F1 и Nero di Toskana F1 - на NFT технологии.
... Leaves are harvested for fresh consumption, salads and cooked dishes due to their high nutritional value. A. dubius contains high quality proteins, carbohydrates, antioxidants and dietary fibre which can be used to prevent cancer, diabetes and arteriosclerosis [10]. The vegetables are also rich sources of vitamins like A,C, K, folate and minerals like potassium ,phosphorous, calcium and magnesium [1,16] Amaranthus has a very short shelf life after harvesting, which put constraint on production, marketing and consumption, which forces farmers to sell soon after harvest [13]. ...
Leafy vegetables are a rich source of vitamins, Minerals and antioxidants, their consumption among resource-poor populations in developing countries will help to mitigate these deficiencies. Post-harvest losses of leafy vegetables are estimated to be over 30% and are generally caused by poor handling and storage conditions. But, post harvest preservation of the quality of these vegetables is necessary for poor populations in developing countries. It is in this direction the present study is taken up. In the current research, leaves of Amaranthus dubius was used to determine the changes in morphological, physiological and biochemical properties of the vegetable under modified storage at low temperature. The vegetables were kept in active bags and stored in low temperatures at 18 0 C and relative humidity of 75%. The leaf samples were taken at 1-day interval for measuring morphological and biochemical parameters like chlorophyll, carotenoid and carbohydrate content. On an average the chlorophyll content showed 35 % decrease after 5 days and 12% decrease on 3 rd day, Carotenoid, a precursor of vitamins showed 44 % decrease after 5 days and 15% decrease after 3 days. The carbohydrate content showed 42% decrease after 5 days and 15% decrease after 3 days. The loss in carotenoid is highest when compared to other parameters. Based on this study, it is suggested that the use of active bag combined with low temperature storage for three days will extend the shelf life and preserve optimum amount of nutrients in Amaranthus dubius.
... The reducing power of these phytochemicals was related to the number and position of hydroxyl groups in their structure (Pulido et al., 2000). Lastly, the TAC assay evaluated the overall antioxidant potential of a sample by measuring its ability to scavenge stable radical The flavonoid composition of the four samples analyzed in this study was found to be distinct from previous reports (Hertog et al., 1992;Miean & Mohamed, 2001;Trejo-Téllez et al., 2019). Interestingly, kaempferol, a flavonoid commonly associated with Brassica species, was not discovered in any of the samples. ...
This study investigated the phytochemical composition and in vitro biological activities of leaf and seed extracts of Brassica oleracea var. elongata. Phytochemical screening revealed the presence of alkaloids, flavonoids, terpenoids, phenols, tannins, saponins, and reducing sugars in both methanolic and aqueous extracts. Quantitative analysis showed that methanolic extracts contained higher levels of polyphenols and flavonoids than aqueous extracts, with methanolic seed extract exhibiting the highest polyphenol content (4.399±0.14 mg GAEq/g). High-performance liquid chromatography analysis identified significant concentrations of gallic acid (1180.20 µg/100 mg), chlorogenic acid (8323.831 µg/g), and quercetin (5512.58±0.02 µg/100 mg) in extracts. Antioxidant activity assays demonstrated potent effects, with methanolic leaf extract showing the strongest 2,2-diphenyl-1-picryl-hydrazyl (DPPH) scavenging activity (IC50: 0.058±0.001 mg/mL) and aqueous leaf extract exhibiting the highest activity in the β-carotene bleaching method (EC50: 0.049±0.001 mg/mL). Ultraviolet protection potential was assessed, revealing promising sun protection factor (SPF) values of all extracts, with methanolic seed extract having the highest SPF of 45.58±10. Evaluation of anti-inflammatory activity revealed the aqueous leaf extract’s remarkable inhibition of inflammation (94.8%). Antimicrobial assays showed notable antibacterial effects, particularly against Gram-positive bacteria. These findings underscore the therapeutic potential of Brassica oleracea extracts and warrant further exploration into their applications in both pharmaceutical and cosmetic industries.
... A growing body of nutritional and pharmacological evidence links a diet rich in fruits and vegetables to a reduced risk of cardiovascular disease, cancer, diabetes, and other severe chronic diseases [1,2]. The main benefit of such a diet may be the increased intake of antioxidants, including carotenoids, tocopherols, and phenolic compounds [3]. ...
This study presents the metabolomic profiles of the four Ribes species (Ribes pauciflorum Turcz., Ribes triste Pall., Ribes dicuscha Fisch., and Ribes aureum Purch.). The plant material was collected during two expeditions in the Russian Far East. Tandem mass spectrometry was used to detect target analytes. A total of 205 bioactive compounds (155 compounds from polyphenol group and 50 compounds from other chemical groups) were tentatively identified from the berries and extracts of the four Ribes species. For the first time, 29 chemical constituents from the polyphenol group were tentatively identified in the genus Ribes. The newly identified polyphenols include flavones, flavonols, flavan-3-ols, lignans, coumarins, stilbenes, and others. The other newly detected compounds in Ribes species are the naphthoquinone group (1,8-dihydroxy-anthraquinone, 1,3,6,8-tetrahydroxy-9(10H)-anthracenone, 8,8′-dihydroxy-2,2′-binaphthalene-1,1′,4,4′-tetrone, etc.), polyhydroxycarboxylic acids, omega-3 fatty acids (stearidonic acid, linolenic acid), and others. Our results imply that Ribes species are rich in polyphenols, especially flavanols, anthocyanins, flavones, and flavan-3-ols. These results indicate the utility of Ribes species for the health and pharmaceutical industry.
... Because they exist in considerable amounts in only a few regularly eaten plants, their dietary intake is quite low. Red pepper [37] and celery [38] are the most crucial sources. ...
Flavonoids are polyphenolic substances present in plants having a fundamental structure of C6–C3–C6. This structure contains a pair of aromatic rings that are interconnected by a 3‐C chain, resulting in a heterocycle. These are essential components of the human diet, and are found in vegetables, fruits, and beverages that include wines, tea, chocolate, and fruit juices. Except for flavonols, all flavonoids contained in foods are glycosylated, and glycosylation influences absorption. The small intestine absorbs flavonoids into the bloodstream, where they are distributed throughout the body. Their metabolism occurs in the liver and tissues, resulting in metabolites (such as quercetin‐3‐glucuronide, kaempferol‐7‐glucuronide, and isorhamnetin) with altered chemical properties that interact with cellular processes and exhibit antioxidant, anti‐inflammatory, and many other salutary effects. During the process of oxidation, the generation of numerous unstable and highly reactive substances known as free radicals occurs. These highly reactive substances, namely, ROS, cause oxidative stress, a phenomenon closely related to inflammation that results in serious cellular harm. The presence of numerous hydroxyl groups (‐OH) in flavonoids enables them to act as strong antioxidants and neutralize oxidative stress during physiological events. In recent times, attention has been raised to the significance of flavonoids and their potential role in disease prevention and intervention. Present‐day study efforts in the field of flavonoids mostly focus on the identification of plant‐based or nutritious flavonoids with the objective of investigating their potential medical uses and examining their physiological and pharmacological activity in relation to several chronic disorders.
... Also, Jayanta et al., [154] found that anthocyanin-rich foods significantly prevented elevation in serum and tissue lipids, circulating levels of cardiac and hepatic damage markers, and resulted in excretion of lipids through faces. Data of the present study with the others indicated that the possible mode of action of blood lipid profile improving of the tested plant parts could be explained by one or more of the following mechanisms including enhance the antioxidant and anti-inflammatory activities [20,125,155,156,157], reduce the LDL oxidation and endothelial cell damage which is believed to be involved in the early development of atherosclerosis [151,158,159], inhibit consumption of antioxidant itamins such as α-tocopherol [158,160], protect human serum paraxonase (PON 1) activities [159,161], bind to albumin and never incorporated into the LDL particle [162]. ...
The present study aims to investigate the effectiveness of psyllium husk, green coffee, orange peel and their mixture on obesity Induced by high fat diet (HFD) in rats. Rats (n= 72 rats), were divided into two main groups, the first group, normal control, (Group 1, 6 rats) still fed on basal diet (BD) and the other main group (66 rats) was used for obesity induction by feed with HFD for four weeks then classified into eleven equal sub groups as follow:. Group 2 (G2), model control, fed on BD only as a positive control (rats with obesity), groups (3-10), fed on BD containing 2.5 and 5.0% of psyllium husk, green coffee, orange peel and their mixture, and groups (11-12) fed on BD containing 1 and 2% of CHROMAX (one of the dietary supplements commonly used in obesity management) for comparative study. Rats feeding on HFD (model control) for 4 weeks leads to increase the BWG, FI and FER than the normal group by the rate of 161.7, 47.6 and79.1%, respectively. Biochemical analysis data indicated that obesity induced a significant (p≤0.05) decrease the hemoglobin (-34.4%) and RBCs (-46.7%), serum albumin (-63.9%) and globulin (-51.7%), increased liver functions enzymes activities (AST, 147%, ALT 163.2% and ALP, 107.6%), blood glucose (151.5%), serum lipid profile (TGs, 83.3%, TC, 75.9% and LDL-c , 200.1%) compared to normal controls. Intervention with selected plant parts in feeding rats protocol for 4 weeks led to significantly (p≤0.05) improvement on the all biological and biochemical parameters of the obese rats by different rates. The best results for all previous measures were recorded in the groups of rats that were fed on a mixture of selected plant parts, followed by the groups that were fed on green coffee, orange peel and psyllium husks, respectively. Also, the feeding intervention with a mixture of plant parts was more effective in obesity treatment when compared to CHROMAX. In conclusion, the results of present study provide a basis for the use of selected plant parts for the prevention or early treatment of obesity and its related complications, but completing this important topic requires the necessity of conducting more studies and research in the future.
... The leaves of wild leeks or ramps (100 g fresh weight) were described to hold 32.5 mg of kaempferol [221]. Kaempferol quantity in other plant sources are gooseberry yellow (16 mg/kg) [222], papaya shoot (453 mg/kg), pumpkin (372 mg/kg), white radish (38 mg/kg) [219], and beans (14 mg/kg) [223]. There are no established dietary recommendations for flavonol intake for individuals [224,225]. ...
Natural products and their bioactive compounds have been used for centuries to prevent and treat numerous diseases. Kaempferol, a flavonoid found in vegetables, fruits, and spices, is recognized for its various beneficial properties, including its antioxidant and anti-inflammatory potential. This molecule has been identified as a potential means of managing different pathogenesis due to its capability to manage various biological activities. Moreover, this compound has a wide range of health-promoting benefits, such as cardioprotective, neuroprotective, hepatoprotective, and anti-diabetic, and has a role in maintaining eye, skin, and respiratory system health. Furthermore, it can also inhibit tumor growth and modulate various cell-signaling pathways. In vivo and in vitro studies have demonstrated that this compound has been shown to increase efficacy when combined with other natural products or drugs. In addition, kaempferol-based nano-formulations are more effective than kaempferol treatment alone. This review aims to provide detailed information about the sources of this compound, its bioavailability, and its role in various pathogenesis. Although there is promising evidence for its ability to manage diseases, it is crucial to conduct further investigations to know its toxicity, safety aspects, and mechanism of action in health management.
... Onions have a higher capacity to reduce serum uric acid levels than quercetin aglycone alone. This could be due to flavonoids in onions having higher intestinal absorption and bioavailability than quercetin (Hertog et al., 1992;Haidari et al., 2008). In the present investigation, onion as a whole food having various concentrations of quercetin was explored for its potent effect to reduce uric acid levels. ...
Introduction: Onions (Allium cepa L.) are excellent sources of bioactive compounds and phytochemicals such as allicin, quercetin, fisetin, and other sulfurous compounds. Therefore, our study aimed to investigate the effects of dried onion powder on growth performance, nitrogen balance, and biochemical parameters in Wistar albino rats with induced hyperuricemia.
Methods: A total of 24 rats were randomly divided into four groups, with six in each group: HU (positive control) and HOT1, HOT2, and HOT3 groups, which received a diet containing onion powder at concentrations of 11.13, 14.84, and 18.61 g/100 g, respectively. Hyperuricemia was induced in rats by administering a new formulation intraperitoneally (250 mg/kg potassium oxonate) and orally (40 mg/kg potassium bromate) daily for 14 days. After confirmation of hyperuricemia induction, rats were fed with onion-treated diets with various concentrations of quercetin for 21 days.
Results: Significant decreases (p ≤ 0.05) in serum uric acid, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, total cholesterol, and low-density lipoprotein were observed. An increasing trend (p ≤ 0.05) in the levels of hemoglobin (Hb), white blood cell (WBC), red blood cell (RBC), and platelet count was observed. An improvement in the levels of serum high-density lipoprotein, triglycerides, blood urea nitrogen, serum creatinine, serum total protein and neutrophils, lymphocytes, and monocytes was observed. A positive progress (p ≤ 0.05) was observed in growth performance and nutrient digestibility.
Conclusion: In conclusion, a significantly lower uric acid level was observed in rats fed with HOT2 diet. Based on the ratio of the surface area (human/rat), the best recommended dose of onion for the incidence and prevention of hyperuricemia is 189.95 g, corresponding to the dose of 204 mg/day of quercetin in humans.
... Finally, it is important to know the main contributors of luteolin derivates in vegetal food. After a comprehensive data comparison [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61], it was found that peppermint, celery, Mexican oregano, tansy leaf, fenugreek seeds, rosemary, sage, and rooibos are the richest sources of luteolin derivatives in human food. Also, it was found that luteolin-O-glycosides are more prevalent than luteolin-C-glycoside. ...
Luteolin derivates are plant compounds with multiple benefits for human health. Stability to heat and acid hydrolysis and high resistance to (auto)oxidation are other arguments for the laden interest in luteolin derivates today. The present study was designed to compare the in silico and in vitro anti-proliferative potential of two luteolin derivates, luteolin-7-O-glucoside/cynaroside (7-Lut) and luteolin-8-C-glucoside/orientin (8-Lut). In silico investigations were carried out on the molecular target, namely, the human dual specificity tyrosine phosphorylation-regulated kinase 2 (DYRK2) in association with its natural ligand, curcumin (PDB ID: 5ZTN), by CLC Drug Discovery Workbench v. 1.5.1. software and Molegro Virtual Docker (MVD) v. MVD 2019.7.0. software. In vitro studies were performed on two human tumor cell lines, glioblastoma (U87) and colon carcinoma (Caco-2), respectively. Altogether, docking studies have revealed 7-Lut and 8-Lut as effective inhibitors of DYRK2, even stronger than the native ligand curcumin; in vitro studies indicated the ability of both luteolin glucosides to inhibit the viability of both human tumor cell lines, up to 85% at 50 and 100 µg/mL, respectively; the most augmented cytotoxic and anti-proliferative effects were obtained for U87 exposed to 7-Lut (IC50 = 26.34 µg/mL). The results support further studies on cynaroside and orientin to create drug formulas targeting glioblastoma and colon carcinoma in humans.
... A number of studies on flavonoids have focused on their antioxidant properties, e.g., [160][161][162][163] and on how the consumption of natural products rich in flavonoids has beneficial health effects. 158,164,165 Flavonoids are suggested to have beneficial effects on various diseases, including cancer, neurogenerative disorders, and cardiovascular disease. 160,[166][167][168][169][170][171][172] Flavonoids modulate cell signaling pathways, but their precise mechanism of action is unclear. ...
Natural products, such as herbal medicinal products, food supplements, and functional food, are widely used to support well-being and for promoting health. In general, the effects of using these products are desired and beneficial, but unexpected adverse effects might also occur, especially when natural products are used with medication. Consumers do not often even know that they are exposed to bioactive compounds that might interact with the body and have effects on their well-being. One of the objectives of the World Health Organization is to promote herb–drug interaction monitoring, and it is important to know how marketed preparations and compounds from common foods interact when they are absorbed. In this review, we describe how a Caco-2 cell absorption model has been used to study how natural products, such as flaxseed, rapeseed, purple loosestrife, pine, echinacea, certain berries and herbs, anthranoid laxatives, and traditional medicinal plants, affect the absorption of co-administered drugs. We discuss the types of interactions and adverse effects that might occur and their possible reasons. Overall, we conclude that the Caco-2 cell absorption model is a useful tool for studying the absorption of natural products with drugs; and that to enable the safe use of natural products with medicines, concomitant use should be studied.
... Notably, the purple variety of pitanga is rich in anthocyanins, flavonoids, and carotenoids (Lima et al. 2005). Studies suggest that metabolites such as phenolic compounds, flavonoids, anthocyanins and others present in fruits and plants play a preventive nutritional role by providing antioxidant protection to the body, mitigating oxidative stress caused by free radicals in cells (Hertog et al. 1992;Paganga et al. 1999;Rechner et al. 2002). Recently, our research group demonstrated that purple pitanga ethanolic extract (PPE) was able to block the effects of MPTP on memory impairment by modulating the BDNF pathway (Savall et al. 2023). ...
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been widely used due to its specific and reproducible neurotoxic effect on the nigrostriatal system, being considered a convenient model of dopaminergic neurodegeneration to study interventions therapeutics. The purple pitanga (Eugenia uniflora) is a polyphenol-rich fruit with antioxidant and antidepressant properties, among others. Therefore, this study investigated the effect of purple pitanga extract (PPE) on acute early oxidative stress induced by intranasal 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration in rats. Male Wistar rats were pre-treated orally with PPE (1000 mg/kg) or vehicle. After 24 h, MPTP (0.1 mg/10µL/nostril) or vehicle was administered bilaterally into the animal’s nostrils, and 6 h later, the olfactory bulb (OB), striatum (ST), and substantia nigra (SN) were collected to evaluate the oxidative stress parameters. Our findings revealed that OB and SN were the most affected areas after 6 h of MPTP infusion; an early increase in reactive oxygen species (ROS) levels was observed, while pretreatment with a single dose of PPE prevented this increment. No differences in thiobarbituric acid reactive species (TBARS) and 3-nitrotyrosine (3-NT) formation were observed, although 4-hydroxy-2-nonenal (4-HNE) levels increased, which is the most toxic form of lipid peroxidation, in the MPTP group. The PPE pretreatment could prevent this increase by increasing the NPSH levels previously decreased by MPTP. Furthermore, PPE prevents the Na+/K + ATPase strongly inhibited by MPTP, showing the neuroprotective capacity of the PPE by inhibiting the MPTP-generated oxidation. Thus, we demonstrated for the first time the antioxidant and neuroprotective effects of PPE against the early MPTP neurotoxicity.
... Vitamin C plays a role in plant responses to abiotic stresses, including osmotic stress, drought, chilling, heat, and heavy-metal toxicity. Vitamin C has been found to be responsible for 3% of the total antioxidant power of R. idaeus fruits [81]. It is estimated that the minimum daily requirement of vitamin C in adults is 40-60 mg. ...
Rubi idaei fructus is a source of nutritionally important bioactive chemical compounds, mainly antioxidants, which strengthen the immune system and can be used in the prophylaxis and adjuvant therapies of many oxidative stress-induced diseases. There are no literature reports presenting a comprehensive comparative analysis of the antioxidant activity and nutritionally relevant metabolites contained in the fruits of repeat-fruiting raspberry cultivars, which are commonly grown in Europe. The aim of this study was to carry out a comparative analysis of the antioxidant potential (Folin–Ciocalteu, DPPH, FRAP), the content of selected primary and secondary metabolites, and the qualitative and quantitative composition of amino acids and fatty acids in the fruits of R. idaeus cv. ‘Pokusa’, ‘Polana’, and ‘Polka’. The fruits of the analyzed cultivars have a low caloric value (171–219 kcal/100 g); low content of available carbohydrates (6–6.6%) and total carbohydrates (3.4–4.8%); and high levels of dietary fiber (4.7–5.8%), vitamin C (22.8–27 mg/100 g), anthocyanins (25.1–29.6 mg/100 g), and flavonoids (0.5–2.6 mg/100 g). The fruits were found to contain valuable unsaturated fatty acids (35–60%), especially MUFAs with dominant oleic, elaidic, palmitic, and erucic acids and PUFAs (α-linolenic, eicosapentaenoic, and linoleic acids). MUFAs from the ω-9 group accounted for 12–18%, whereas the content of PUFAs from the ω-3 and ω-6 groups was in the range of 15–23 and 6–21%, respectively. Exogenous amino acids, accounting for 56–62%, were dominated by leucine, phenylalanine, and lysine. The following order of the total polyphenolic content was established in the fresh fruit juice from the analyzed cultivars: ‘Pokusa’ < ‘Polana’ < ‘Polka’. The different antioxidant capacity assays used in the study confirmed the high antioxidant potential of the fruits and fresh juice from the three R. idaeus cultivars. This indicates that raspberry fruits can serve as a source of nutrients and can be used as a valuable supplement in a healthy human diet and a raw material in the pharmaceutical and cosmetic industries.
... Kandungan flavonoid pada seledri, yaitu apigenin berfungsi sebagai agen antiperadangan dan membantu menurunkan sekresi hormon kortisol di dalam darah. Flavonoid adalah jenis polifenol yang terkonsentrasi di bagian daun, buah, biji, dan bunga (Hertog et al., 1992;Miller, 2001). Aprilia (2010) membuktikan bahwa kuersetin bekerja sebagai anti-oksidan yang berguna mengatasi radikal bebas. ...
Tujuan penelitian ini adalah mengetahui, mengkaji, dan menganalisis potensi seledri sebagai herba antistres dan imunomodulator dengan cara menghambat sekresi kortisol plasma pada tikus Wistar (Rattus norvegicus) yang diinduksi kejutan listrik. Penelitian ini merupakan penelitian eksperimental laboratoris, pre and postest with control group design. Sampel yang digunakan adalah 13 ekor tikus Wistar yang dibagi dalam 3 kelompok: P0, kelompok kontrol (kejutan listrik); P1, kejutan listrik + ekstrak seledri 0,14 mg; dan P2, kejutan + ekstrak seledri 0,72 mg. Kejutan listrik dan ekstrak seledri masing-masing diberikan selama 7 hari. Kadar kortisol diukur menggunakan metode enzyme-linked immunosorbent assay (ELISA). Analisis data menggunakan uji analisis varian satu arah. Hasil penelitian menunjukkan bahwa nilai rata-rata kadar kortisol serum kelompok P0 sebelum dan setelah diberikan perlakuan mengalami peningkatan, sedangkan kelompok P1 dan P2 mengalami penurunan (P0= 1,88 vs 3,65; P1= 4,59 vs 2,63 dan P2= 3,00 vs 2,99). Pemberian ekstrak seledri cenderung menurunkan kadar kortisol serum meskipun secara statistik tidak berbeda secara signifikan (P>0,05). Disimpulkan bahwa ekstrak seledri belum sepenuhnya berperan sebagai herbal antistres pada tikus Wistar yang mengalami stres.
... The presence of phenolic compounds in plant extracts contributes significantly to their antioxidant potential (Dudonné et al., 2009). Part of this AOA comes from flavonoids, low molecular weight polyphenolic compounds distributed in fruits and vegetables (Hertog et al., 1992). For their part, betalains are powerful free radical scavengers that act as efficient antioxidants in biological models (Cano et al., 2017). ...
Postharvest quality, quantification of betalains, phenolic compounds, and antioxidant activity of peel, pulp, and juice of fruits of three prickly pears (Opuntia ficus-indica L. Mill.) cultivars of Colegio de Postgraduados in México, were measured. The red and orange cultivars showed outstanding features of postharvest quality (size, texture, TSS and pulp and juice content) highest content of betalains and phenolic compounds. Therefore, highest antioxidant activity. In general, the highest content of bioactive compounds was detected in the peel, besides the content in pulp and juice did not show statistically significant differences. Phenolic content is very high in comparison with other fruits. Antioxidant activity was measured by three assays:FRAP, ABTS, and DPPH. Three cultivars showed a high correlation between antioxidant activity and phenolic compounds. The methodologies used in this work are a very useful tool for the quantification of bioactive compounds in O. ficus-indica fruit tissues.
... The identified flavonoids in our study are in line with the findings of Vågen and Slimestad [7], and Hedges and Lister [48], who state that onions contain flavonoids in various amounts, namely quercetin, isorhamnetin, and kaempferol and their derivatives. As shown by Golubkina and Carouso, onion ranks in first place for the concentration value of quercetin within a group of 28 vegetables and nine fruits [49] of which the antioxidant capacity is known to be the highest of the most common plant flavonoids [40]. Moreover, authors stated that at least eight flavonols are present in onions, such as quercetin-3-glucoside, quercetin-4 -glucoside, quercetin-7-glucoside, quercetin-3,4 -diglucoside, quercetin-7,4diglucoside, quercetin 3,7-diglucoside, quercetin 3,7,4 -triglucoside, and isorhamnetin-4 -glucoside, of which quercetin-4 -glucoside and quercetin-3,4 -diglucoside are considered to be the most abundant, accounting for more than 85% of total flavonol content in onions [7,48]. ...
The Mediterranean area is especially rich in old, both sweet and pungent, varieties of onion. The synthesis of phytochemicals takes place concurrently with the overall development and maturation of vegetables; however, it is unclear whether there is a correlation between onion bulb size and antioxidant compound content, antioxidant capacity, and nutritional parameters and what the origin of these variations is. The aim of this work was to investigate the biochemical and nutritional aspects of the sweet onion landrace “Premanturska kapula”, as well as to investigate the influence of onion bulb size on onion phytochemical and nutritional profile. The sweet onion landrace “Premanturska kapula” has a high soluble sugar content, a high antioxidant capacity, and a high phenolic compound content. Quercetin-3,4′-diglucoside and quercetin-4′-glucoside were the major flavonols, while protocatehuic acid was the major phenolic acid detected. The choice of onion bulb size can impact the profile of the sugars present, with large bulb sizes favoring higher sucrose and fructooligosaccharides content compared to small bulb sizes which were more abundant in glucose. The total sugars or bulb dry matter were not affected by bulb size. Phenolic compounds were more abundant in smaller bulb sizes, thus indicating a link between bulb development and phenolic compound allocation within the plant. This link possibly derived from agronomic practices such as bare-root transplants, or even open pollination which causes a broader genetic variability. From a consumer perspective, it can be a choice between the small and medium bulb sizes on one hand, which are more abundant in polyphenolics and simple sugars, or on the other hand, the larger bulbs which are more abundant in fructooligosaccharides known to carry excellent health benefits.
... Total phenolic content (TPC) was measured according to the method of Hertog et al. [22], with minor modifications. Samples of 1 g powdered plant material were mixed with 10 mL 99.8% (v/v) methanol and vortexed for 30 s. Subsequently, the mixture was shaken (Orbital shaker 261, Labotec (PTY) LTD, Durban, South Africa) overnight at ambient temperature. ...
The exploring of biostimulant sources is important for sustainable agriculture. Although all parts of the moringa plant (Moringa oleifera Lam.) are rich in phytohormones and phytochemicals which may be utilised as a potential plant growth enhancer, most attention has been placed on its leaves as a possible biostimulant for enhancing productivity of plants. Little has been reported on moringa seed extract (MSE) as a growth enhancer on medicinal plants. Thus, this study investigated the efficacy of MSE doses (water spray as control, MSE at 2, 4, 6 and 8%) on growth attributes, mineral content and phytochemical compositions of cancer bush plants (Lessertia frutescens L.) grown during the winter–spring and spring–summer seasons of 2021. A gradual increase in growth characteristics, chlorophyll content, phenols and flavonoid contents was recorded in all concentrations of MSE-treated plants compared with controls. Furthermore, all levels of MSE effectively enhanced the concentrations of macronutrients such as calcium, magnesium, phosphorus, nitrogen and potassium as well as micronutrients comprising copper, zinc, iron, manganese and sodium of cancer bush plants relative to untreated plants. Both 6 and 8% MSE concentrations showed high productivity, minerals and phytochemical constituents in cancer bush plants in comparison with 2 and 4% MSE treatments. Overall, the findings of this study demonstrated that, even at low concentrations, MSE can be successfully applied as a biostimulant to improve the growth and biochemical attributes of cancer bush plants.
The usability of flavonoids, which have numerous functional benefits, is limited by their low solubility. In this study, microorganisms were isolated from the soil of a buckwheat farmland located in Pyeongchang, Republic of Korea, to identify potential agents for flavonoid bioconversion. Strain 3P-1, which exhibited 98.9% 16S rRNA gene sequence similarity to Bacillus licheniformis strain IND706, demonstrated the ability to utilize flavonoids during fermentation. During the 7-day fermentation process with strain 3P-1, a significant decrease in quercetin content was observed, accompanied by the generation of an unknown compound. High-performance liquid chromatography coupled with mass spectrometry analysis of the unknown compound revealed its molecular weight. Among the four potential candidates identified, isoquercetin was determined to be the most likely agent for flavonoid bioconversion based on its biosynthetic pathway and substrate specificity, as well as known characteristics of strain 3P-1. These findings suggest that the isolated strain 3P-1 has substantial potential as a bioconversion agent for transforming quercetin to isoquercetin, which enhances its bioavailability.
Molecules with potency and low toxicity are the leading army in the battlefield of multidrug resistance. Quercetin is found in abundance in the nature as a potent flavonoid and bears the tag of flavonoid paradox due to the poor bioavailability, however, it still possess distinct systemic actions, and this marks curiosity in the research field. The present study elaborates targeted in silico and simulation approaches of newly designed quercetin analogs toward their anticancer and antifungal properties by screening against human epidermal growth factor receptor and lanosterol C14‐alpha demethylase receptors. The molecules were investigated pharmacokinetically via drug‐likeness, toxicity prediction (lethal dose, LD50), PASS prediction, molecular docking, molecular dynamics simulation, and their quantum mechanics have been measured using molecular orbital calculations through highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) calculations. The prediction from Pa > Pi scores displayed its potential for squalene epoxide inhibitors, antimycobacterial, and antineoplastic activities and also showed prospectively better molecular docking scores against the selected targeted enzymes. Among the series, QIz II stood out as a compelling inhibitor; showcasing highest binding affinity with fungal protein by impressive docking score of −10.7 kcal/mol. Compound QIz XX demonstrated the highest binding affinity of −9.31 kcal/mol with the anticancer protein.
The study aimed to evaluate the antioxidant potential and microbial composition of edible fermented vegetable roots available on the Polish market, including celeriac, carrot, beetroot, radish, and white radish. The microbiological determinations were conducted according to European Standards. The total phenol content (TPC) was measured by the Folin–Ciocalteu (FC) method, while the total antioxidant capacity (TAC) was analyzed by CUPRAC and DPPH assays. The mean recovery for FC, CUPRAC, and DPPH was in the range of 104–105%, 97–102%, and 96–108%, while the precision amounted to 2.3, 2.75, and 5.99, respectively. The average antioxidant potential among all fermented roots decreased in the following order: beetroot > celeriac > radish > carrot > white radish. In the case of microbiological analyses, no bacteria were found in pasteurized products. However, among unpasteurized vegetables, 7 out of 11 products met the FAO/WHO criteria for probiotic foods, as they contained a sufficient number of lactic acid bacteria and lacked Escherichia coli. None of the tested products were contaminated with Bacillus cereus, Salmonella spp., Enterococcus spp., or spore-forming anaerobic bacteria. Moreover, chemometric techniques such as the Kruskal–Wallis test and cluster analysis were used to differentiate samples in view of their antioxidant potential. These analyses demonstrated the similarity of vegetable samples from the Apiaceae and Brassicaceae families while highlighting differences in antioxidant potential compared to samples from the Amaranthaceae family.
Onions are well-known vegetables that offer various health benefits. This study explores the impact of onion extracts on gut microbiome using an in vitro fecal incubation model and metabolome analysis. Fecal samples were collected from 19 healthy donors and incubated in the presence or absence of onion extracts for 24 h. To reduce inter-individual variability in the gut microbiome, we employed enterotyping based on baseline fecal microbiota: 14 subjects with a Bacteroides-dominant type (enterotype B) and 5 subjects with Prevotella-dominant type (enterotype P). Alpha diversity was significantly reduced in the onion-treated group compared to the non-treated control group in both Bacteroides- and Prevotella-dominant types. However, significant structural differences in bacterial communities were observed based on weighted UniFrac distance. Notably, short-chain fatty acid (SCFA)-producing bacteria, such as Bifidobacterium_388775, Feacalibacterium, and Fusicatenibacter, were overrepresented in response to onion extracts in enterotype B. Furthermore, genes related to butyrate production were significantly overrepresented in the onion-treated group within enterotype B. Consistent with the enriched taxa and the predicted metabolic pathways, SCFAs and their related metabolites were significantly enriched in the onion-treated group. Additionally, tryptophan metabolism-derived metabolites, including indolelactate (ILA) and indolepropionate (IPA), were elevated by 4- and 32-fold, respectively, in the onion-treated group compared to the control group. In vitro growth assays showed an increase in lactobacilli strains in the presence of onion extracts. These results provide evidence that onion extracts could serve as promising prebiotics by altering gut microbial structure and promoting the production of beneficiary metabolites, including SCFAs and indole derivatives, and enhancing the growth of probiotics.
IMPORTANCE
This study is significant as it provides compelling evidence that onion extracts have the potential to serve as effective prebiotics. Utilizing an in vitro fecal incubation model and enterotyping to reduce inter-individual variability, the research demonstrates how onion extracts can alter gut microbial structure and promote the production of beneficial metabolites, including SCFAs and indole derivatives like ILA and IPA. Additionally, onion extract treatment enhances the growth of beneficial probiotics. The findings underscore the potential of onion extracts to improve gut health by enriching specific beneficial bacteria and metabolic pathways, thereby supporting the development of functional foods aimed at improving gut microbiota composition and metabolic health.
The demand for biotics as alternatives to antibiotics that promote growth and lessen the use of antimicrobials in poultry farms is fueled by recent worldwide regulations and consumer expectations. Phytogenic substances are becoming increasingly valuable options because many of these natural compounds possess anti-inflammatory and antioxidant properties that are only less commercialized. The usage of phytogenic substances can also help maintain a balance of healthy microorganisms in the gut, which is beneficial for the digestive system to withstand various chronic stressors, both infectious and non-infectious. Although some phytogenic substances are commercially available, these are typically hampered by inconsistencies in their effectiveness, low bioavailability, and low stability. This chapter discusses the current and potential phytogenic compounds that can exert antioxidant and anti-inflammatory properties to improve poultry production and restore intestinal microbiota. Additionally, the main challenges still related to phytogenic products will be discussed.
Horticulture crops possess numerous functional properties with the potential to yield nutritional constituents or nutraceuticals, making them exemplary examples of edible plant harvests. Nutrients and secondary metabolites derived from various parts of horticulture crops exhibit several health-promoting properties. Nutrients, also referred to as primary metabolites, encompass carbohydrates, fatty acids, amino acids, and vitamins. These play crucial roles in various biological processes such as protein synthesis, hormone synthesis, respiration, photosynthesis, and growth and development. In contrast, secondary metabolites, including phenolic/polyphenolic compounds, alkaloids, terpenoids, and sulfur-containing compounds, do not directly contribute to the development and growth of plants. Instead, they serve as defenders against microorganisms, function as signal molecules under stress conditions, attract pollinators, and determine the color of different horticulture crops. Consequently, the beneficial effects of the diverse nutrients and secondary metabolites present in horticulture crops for their health-promoting properties continue to garner increasing attention. Furthermore, there is a growing interest in advancing techniques for the extraction, separation, and quantification of these valuable bioactive components from horticulture crops. This is to facilitate their use as value-added ingredients in the nutraceutical and food industries. This chapter provides comprehensive information on advanced analytical techniques for the analysis of nutrients and secondary metabolites in different horticulture crops.
Coronaviruses cause diseases of the respiratory tract, gastrointestinal tract and central nervous system, which threaten human health and contribute to economic losses. Innovative production technologies make it possible to use bioactive compounds as antiviral agents. Most fruits, vegetables and plant products contain flavonoids. Numerous studies have demonstrated the health-promoting effect of this group of compounds resulting from their antioxidant potential. The activity of an antioxidant in the body is the result of many factors that modulate the reactivity and physicochemical properties, among which the chemical structure is the most important. Bioinformatics tools using molecular modeling often precede research using in vitro and in vivo methods. The aim of this review is to present the mechanism of antiviral action of flavonoids against SARS-CoV-2, responsible for COVID-19. Studies using virtual molecular docking models were collected to test the affinity of flavonoids for key proteins of the SARS-CoV-2 virus replication cycle. Among the flavonoids with antiviral activity, the most active were apigenin, luteolin, isorhamnetin, kaempferol, myricetin, quercetin, hesperetin, naringenin and genistein. Food products with a high content of these compounds are indicated.
In the context of organic farming, the introduction of a local product to wider markets and an evaluation of storage effects, metabolic and transcriptomic variations in two broccoli rabe genotypes from production cycles of two different years were studied by comparing florets of stored fresh (SF) and packaged (P) for 4 days with those harvested fresh from the field (H). Twenty-five hydrosoluble compounds, including amino acids, carbohydrates, and organic acids, were quantified by untargeted NMR. PCA produced a neat separation among the three commodity statuses with P being the most divergent and SF closer to H. In the packaged florets, carbohydrate levels dropped significantly (over -52%), while the levels of amino acids and organic acids varied. There was an increase in stress-responsive phenylalanine and valine (over 30%) and succinic and α-ketoglutaric acids (over 75%). Compound correlation analyses indicated a carbohydrate sink towards γ-aminobutyric acid (GABA) and lactic acid (LA) metabolism under hypoxic conditions in packaged florets. RNA-seq analysis revealed that over 4000 genes were differentially expressed in SF vs H and 8000 in P vs H. Several CAR and AA pathways were significantly enriched in S and even more significantly in P, when compared to H. A map of gene expression (175 genes) and metabolite contents (14 compounds) was constructed to elucidate the gene routes that lead to accumulation of GABA and LA, known for healthy properties, in P. WGCNA and promoter binding site analyses enabled the identification of transcription factors (bZIP, WRKY, ERF types), interactions, and targeted genes encoding key enzymes in GABA and LA accumulation.
Utilization of herbs for medicinal purpose started in the early history of mankind several thousand years ago.In the last few years, there has been an exponential growth in the field of herbal medicine and gaining popularity both in developing and developed countries because of their natural origin and less side effects. Medicinal plants continue to be an important therapeutic aid for alleviating ailments of humankind. An antioxidant is a molecule capable of terminating the chain reactions that damage cells by removing free radical intermediates and inhibit other oxidation reactions by thereby reducing stress responsible for many degenerative disorders. The aim of the present study was to determine qualitative and quantitative phytochemical and in vitro antioxidant activities of leaf of Green tea, Brahmi and bulb of Onion collected from Bhopal region of Madhya Pradesh. Qualitative analysis of various phytochemical constituents and quantitative analysis of total phenol were determined by the well-known test protocol available in the literature. Quantitative analysis of phenolic content was carried out by Folins Ciocalteau reagent method. The in vitro antioxidant activity of methanolic extract of the leaf and bulb was assessed against DPPH assay method using standard protocols. Phytochemical analysis revealed the presence of phenols, flavonoids, tannins, saponins, alkaloids. The total phenolic content of leaf of Green tea, Brahmi and bulb of Onion was 195.26 ± 12.64, 136.92 ± 21.73 and 112.23 ± 11.36 mg/100mg respectively. The activities of methanolic leaves and bulbs extract against DPPH assay method were concentration dependent with IC 50 values of ascorbic acid and extracts 20.05±1.86 and 55.98±2.56, 104.45±3.13, 144.37±5.45μg/ml respectively. These studies provided information for correct identification of this plant material. The diverse array of phytochemicals present in the plant thus suggests its therapeutic potentials which may be explored in drug manufacturing industry as well as in traditional medicine. Keywords: Green Tea, Brahmi, Onion, Phytochemical constituents, Antioxidant activity
Apigenin is a powerful flavone compound found in numerous fruits and vegetables, and it offers numerous health-promoting benefits. Many studies have evidenced that this compound has a potential role as an anti-inflammatory and antioxidant compound, making it a promising candidate for reducing the risk of pathogenesis. It has also been found to positively affect various systems in the body, such as the respiratory, digestive, immune, and reproductive systems. Apigenin is effective in treating liver, lung, heart, kidney, neurological diseases, diabetes, and maintaining good oral and skin health. Multiple studies have reported that this compound is capable of suppressing various types of cancer through the induction of apoptosis and cell-cycle arrest, suppressing cell migration and invasion, reduction of inflammation, and inhibiting angiogenesis. When used in combination with other drugs, apigenin increases their efficacy, reduces the risk of side effects, and improves the response to chemotherapy. This review broadly analyzes apigenin’s potential in disease management by modulating various biological activities. In addition, this review also described apigenin’s interaction with other compounds or drugs and the potential role of nanoformulation in different pathogeneses. Further extensive research is needed to explore the mechanism of action, safety, and efficacy of this compound in disease prevention and treatment.
Leek (Allium porrum L.), belonging to the Alliaceae family, is a biennial herbaceous plant. It is a tetraploid (2n=32). They are native to Middle Asia, while its secondary centres of development and spread were in Western Asia and the Mediterranean region. Kaempferol is the most significant flavonoid aglycone found in leeks. Leeks are also used as medicine in addition to being a food. The primary health advantages include anti-asthma, antiseptic, diuretic, antioxidant, antibacterial, and antifungal properties. Additionally, it helps shield skin from harm and lowers the risk of gastrointestinal disorders. Leek roots also contain alliin which is non-toxic to the human body and can be used to preserve food and increase its shelf life. Recent studies also reported that leek portions ultrasonic extracts can be used in the food sector to preserve products from oxidation. Furthermore, when frozen unblanched leek slices are packaged with nitrogen after a year in frozen storage, the amount of sulfur compounds in the slices does not increase and the development of an off flavor is inhibited. It can also be stored up to 14 days when stored at modified atmosphere. In conclusion, using contemporary biotechnology techniques, new leek cultivars with increased productivity and adaptability must be created. Other health-related substances like folates and polyphenols, as well as the quantitative assessment of enzyme activities should all be included in future research as they contribute to the potential health benefits of vegetable products.
Flavonoids are a class of polyphenolic compounds that can be classified into six distinct categories, namely isoflavonoids, flavanones, flavanols, flavonols, flavones, and anthocyanidins. These compounds are naturally occurring and can be found in a diverse range of plant species. Flavonoids, a class of bioactive compounds, are mostly obtained through the consumption of vegetables, fruits and plant-derived beverages such as wine, cocoa-based products and green tea. Flavonoids have been demonstrated to exhibit a diverse range of anticancer properties. These include the modulation of activities of enzymes involved in scavenging reactive oxygen species, involvement in cell cycle arrest, induction of apoptosis and autophagy, as well as suppression of cancer cell proliferation and invasiveness. Flavonoids exhibit a dual role in maintaining reactive oxygen species balance. They function as antioxidants in regular physiological conditions, while also demonstrating significant pro-oxidant properties in cancer cells. This prooxidant activity induces apoptotic pathways and downregulates pro-inflammatory signalling pathways. The paper explores the biochemical characteristics, bioavailability, anticancer efficacy, and modes of action of flavonoids.
Aging-related diseases (ARDs) are a major global health concern, and the development of effective therapies is urgently needed. Kaempferol, a flavonoid found in several plants, has emerged as a promising candidate for ameliorating ARDs. This comprehensive review examines Kaempferol's chemical properties, safety profile, and pharmacokinetics, and highlights its potential therapeutic utility against ARDs. Kaempferol's therapeutic potential is underpinned by its distinctive chemical structure, which confers antioxidative and anti-inflammatory properties. Kaempferol counteracts reactive oxygen species (ROS) and modulates crucial cellular pathways, thereby combating oxidative stress and inflammation, hallmarks of ARDs. Kaempferol's low toxicity and wide safety margins, as demonstrated by preclinical and clinical studies, further substantiate its therapeutic potential. Compelling evidence supports Kaempferol's substantial potential in addressing ARDs through several mechanisms, notably anti-inflammatory, antioxidant, and anti-apoptotic actions. Kaempferol exhibits a versatile neuroprotective effect by modulating various proinflammatory signaling pathways, including NF-kB, p38MAPK, AKT, and the β-catenin cascade. Additionally, it hinders the formation and aggregation of beta-amyloid protein and regulates brain-derived neurotrophic factors. In terms of its anticancer potential, kaempferol acts through diverse pathways, inducing apoptosis, arresting the cell cycle at the G2/M phase, suppressing epithelial-mesenchymal transition (EMT)-related markers, and affecting the phosphoinositide 3-kinase/protein kinase B signaling pathways. Subsequent studies should focus on refining dosage regimens, exploring innovative delivery systems, and conducting comprehensive clinical trials to translate these findings into effective therapeutic applications.
Background:
Flavonoids are a widespread category of naturally occurring polyphenols distinguished by the flavan nucleus in plant-based foods and beverages, known for their various health benefits. Studies have suggested that consuming 150-500 mg of flavonoids daily is beneficial for health. Recent studies suggest that flavonoids are involved in maintaining mitochondrial activity and preventing impairment of mitochondrial dynamics by oxidative stress.
Objective:
This review emphasized the significance of studying the impact of flavonoids on mitochondrial dynamics, oxidative stress, and inflammatory response.
Methods:
This review analysed and summarised the findings related to the impact of flavonoids on mitochondria from publicly available search engines namely Pubmed, Scopus, and Web of Science.
Description:
Any disruption in mitochondrial dynamics can contribute to cellular dysfunction and diseases, including cancer, cardiac conditions, and neurodegeneration. Flavonoids have been shown to modulate mitochondrial dynamics by regulating protein expression involved in fission and fusion events. Furthermore, flavonoids exhibit potent antioxidant properties by lowering the production of ROS and boosting the performance of antioxidant enzymes. Persistent inflammation is a characteristic of many different disorders. This is because flavonoids also alter the inflammatory response by controlling the expression of numerous cytokines and chemokines involved in the inflammatory process. Flavonoids exhibit an impressive array of significant health effects, making them an effective therapeutic agent for managing various disorders. Further this review summarised available mechanisms underlying flavonoids' actions on mitochondrial dynamics and oxidative stress to recognize the optimal dose and duration of flavonoid intake for therapeutic purposes.
Conclusion:
This review may provide a solid foundation for developing targeted therapeutic interventions utilizing flavonoids, ultimately benefiting individuals afflicted with various disorders.
Kaempferol, a natural plant-origin flavonoid, exhibits therapeutic anti-inflammatory, antioxidant, anticancer, antidiabetic, and neuroprotective properties. Kaempferol acts within several distinct mechanisms like apoptotic induction in cancer cells, enzymatic inhibition, signalling pathway inhibition, and downregulation in cell viability during the G 2 /M phase of cell division. This review summarizes the therapeutic effects of kaempferol against several health ailments. The recent progress on kaempferol obtained from fruits and vegetables as an antioxidant, anti-inflammatory, anticancer, antidiabetic, and neuroprotective agent and its mechanisms of action are also discussed. In addition, kaempferol has been reported to be present in wastes and byproducts from post-fruit and vegetable processing. Thus, a paradigm shift towards valorizing fruits and vegetable industrial wastes/byproducts to obtain bioactive kaempferol can support the circular economy pillar for generating wealth from waste and for finding a sustainable alternative source.
The chili pepper, also known as Capsicum annuum, is widely grown, consumed and utilized for a variety of health benefits. Its fruits display significant morphological variation. They include phenols, flavonoids, carotenoids, vitamins and capsaicinoids (which make up approximately 90% of the total and are responsible for the typical pungency feeling). They also have antioxidant and hypoglycemic qualities. It has 12 pairs of chromosomes, which makes it genetically diploid. Its applications span from cooking, antioxidants, and pain treatment to weight reduction, boosting the circulatory system and enhancing metabolism. The active component, capsaicin, is known to have pain-relieving, anti-inflammatory and antioxidant properties. Capsaicin is used in topical creams for the treatment of arthritis, neuropathic pain, and other types of chronic pain. In addition, capsaicin has antimicrobial properties and is effective against certain bacteria, viruses, and fungi. Capsicum is well known for its flavor and aroma that’s why it is highly used in salads and different sauces. On the other hand it is also a great antioxidant and much helpful in cancer treatment.
NaCl stress in plants affects various physiological and biochemical processes that result in reduced biomass production. This study aims to determine the aspects of morphological and physiological changes of plants with indications of the induction of secondary metabolism in survival, which is indicated by an indication of an increase in bioactive compounds, including phenolic compounds, flavonoids, single oxygen (O2), hydroxyl radicals (OH-), radicals ( O-2), and superoxide. The clove seed pot experiment under NaCl stress used a randomized block design with three replications. Data are presented as mean ± standard deviation. The significance of the difference between the mean values was tested by analysis of variance, if there was a significant effect, then Duncan Multiple Range Test (DMRT). The results of the NaCl stress study on clove seeds showed fluctuating phenolic and flavonoid content, almost all NaCl treatment with the optimum plant value obtained at a NaCl concentration of 200 mM, with a content of (1.18μg GAE/g) and flavonoids (0.158 g QE/g) ( 1.18μg GAE/g). The antioxidant activity of DPPH, Hydroxyl activity, Superoxide is also affected by the concentration of NaCl
For the first time, quercetin-3-β-ᴅ-glucuronide, quercetin-3-β-ᴅ-glucoside, quercetin-3-(O-malonyl) -β-ᴅ-glucoside and luteolin-7-/9-ᴅ-glucuronide were isolated from lettuce and kaempferol-3-β-D-glucuronide and kaempferol-3-β-ᴅ-glucoside from endives as crystals. The flavonol glucuronides are the main glycosides. Moreover a glycoside was found in endives which is very probably identical with kaempferol-3-(O-malonyl) -β-ᴅ-glucoside.
The "French paradox" (apparent compatibility of a high fat diet with a low incidence of coronary atherosclerosis) has been attributed to the regular drinking of red wine. However, the alcohol content of wine may not be the sole explanation for this protection. Red wine also contains phenolic compounds, and the antioxidant properties of these may have an important role. In in-vitro studies with phenolic substances in red wine and normal human low-density lipoprotein (LDL) we found that red wine inhibits the copper-catalysed oxidation of LDL. Wine diluted 1000-fold containing 10 mumol/L total phenolics inhibited LDL oxidation significantly more than alpha-tocopherol. Our findings show that the non-alcoholic components of red wine have potent antioxidant properties toward oxidation of human LDL.
An HPLC isocratic elution procedure which allows the separation of flavonol aglycones in wine without interference from other phenolics of low molecular weight is described. The method has been applied to the separation, identification and quantitative estimation of flavonol aglycones in ether extracts of different Spanish wines (red and white table wines and Sherry finos). The results suggest that these determinations, associated with other analyses, would permit the chemical characterization of wines.
Keys, A. (84060 Pioppi (SA), Italy), A. Menotti, M. J. Karvonen, C. Aravanis, H. Blackburn, R. Buzina, B. S. Djordjevlc, A. S. Dontas, F. Fldanza, M. H. Keys, D. Kromhout, S. Nedeljkovic, S. Punsar, F. Seccareccia, and H. Toshima. The diet and 15-year death rate In the Seven Countries Study. Am J Epidemiol 1986; 124:903–15
In 15 cohorts of the Seven Countries Study, comprising 11,579 men aged 40-years and “healthy” at entry, 2,288 died In 15 years. Death rates differed among cohorts. Differences In mean age, blood pressure, serum cholesterol, and smoking habits “explained” 46% of variance in death rate from all causes, 80% from coronary heart dIsease, 35% from cancer, and 45% from stroke. Death rate differences were unrelated to cohort differences in mean relative body weIght. fatness, and physical activity. The cohorts differed in average dIets. Death rates were related positively to average percentage of dIetary energy from saturated fatty acids, negatively to dietary energy percentage from monounsaturated fatty acids, and were unrelated to dietary energy percentage from polyunsaturated fatty acids, proteins, carbohydrates, and alcohol. All death rates were negatively related to the ratio of monounsaturated to saturated fatty acids. Inclusion of that ratio with age, blood pressure, serum cholesterol, and smokIng habits as inde pendent variables accounted for 85% of variance In rates of deaths from all causes, 96% coronary heart dIsease, 55% cancer, and 66% stroke. Oleic acid accounted for almost all dIfferences In monounsaturates among cohorts. All- cause and coronary heart disease death rates were low In cohorts with olive oil the main fat Causal relationshIps are not claimed but consideration of characteristics of populations as well as of Individuals withIn populations is urged evaluating risks.
Approximately 200 studies that examined the relationship between fruit and vegetable intake and cancers of the lung, colon, breast, cervix, esophagus, oral cavity, stomach, bladder, pancreas, and ovary are reviewed. A statistically significant protective effect of fruit and vegetable consumption was found in 128 of 156 dietary studies in which results were expressed in terms of relative risk. For most cancer sites, persons with low fruit and vegetable intake (at least the lower one-fourth of the population) experience about twice the risk of cancer compared with those with high intake, even after control for potentially confounding factors. For lung cancer, significant protection was found in 24 of 25 studies after control for smoking in most instances. Fruits, in particular, were significantly protective in cancers of the esophagus, oral cavity, and larynx, for which 28 of 29 studies were significant. Strong evidence of a protective effect of fruit and vegetable consumption was seen in cancers of the pancreas and stomach (26 of 30 studies), as well as in colorectal and bladder cancers (23 of 38 studies). For cancers of the cervix, ovary, and endometrium, a significant protective effect was shown in 11 of 13 studies, and for breast cancer a protective effect was found to be strong and consistent in a meta analysis. It would appear that major public health benefits could be achieved by substantially increasing consumption of these foods.
There is convincing evidence that cellular prooxidant states--that is, increased concentrations of active oxygen and organic peroxides and radicals--can promote initiated cells to neoplastic growth. Prooxidant states can be caused by different classes of agents, including hyperbaric oxygen, radiation, xenobiotic metabolites and Fenton-type reagents, modulators of the cytochrome P-450 electron-transport chain, peroxisome proliferators, inhibitors of the antioxidant defense, and membrane-active agents. Many of these agents are promoters or complete carcinogens. They cause chromosomal damage by indirect action, but the role of this damage in carcinogenesis remains unclear. Prooxidant states can be prevented or suppressed by the enzymes of the cellular antioxidant defense and low molecular weight scavenger molecules, and many antioxidants are antipromoters and anticarcinogens. Finally, prooxidant states may modulate the expression of a family of prooxidant genes, which are related to cell growth and differentiation, by inducing alterations in DNA structure or by epigenetic mechanisms, for example, by polyadenosine diphosphate-ribosylation of chromosomal proteins.
Gastric infection with Helicobacter pylori seems to be a risk factor for gastric cancer. We have conducted a multicentre epidemiological study to investigate this relation further. Our study was designed to look at the relation between the prevalence of H pylori infection and gastric cancer rates in 17 populations from 13 countries, chosen to reflect the global range of gastric cancer incidence. In each centre, about 50 males and 50 females in each of the two age groups 25-34 years and 55-64 years were selected at random from the local population and provided blood samples. Serum samples were assayed for the presence of IgG antibodies to H pylori in a single laboratory. Prevalence rates of H pylori seropositivity were related to local gastric cancer incidence and mortality rates using linear regression. There was a statistically significant relation between the prevalence of seropositivity and cumulative rates (0-74 years) for both gastric cancer incidence and mortality with regression coefficients of 2.68 (p=0.001) and 1.79 (p=0.002), respectively. Our findings are consistent with an approximately six-fold increased risk of gastric cancer in populations with 100% H pylori infection compared with populations that have no infection.
Quercetin inhibited soybean lipoxygenase-1-dependent linoleic acid peroxidation. Two to three μM quercetin was required for 50% inhibition. During the inhibition, quercetin was oxidized. The oxidation was observed as an absorbance decrease at about 380 nm and an absorbance increase at about 335 nm. Inhibition of linoleic acid peroxidation by quercetin seems to be due to reduction by the reagent of the linoleic acid radical formed as an intermediate during lipoxygenation. Quercetin oxidation was suppressed by ascorbate under conditions when ascorbate did not affect lipoxygenase-dependent linoleic acid peroxidation. The results suggest that ascorbate can reduce the quercetin oxidized by the linoleic acid radical back to quercetin. Based on the results, the significance of a redox reaction between oxidized quercetin and ascorbate is discussed.
The rates of hydrolysis of more than a hundred flavonoid glycosides have been measured, using N HCl, β-glucosidase, β-glucuronidase or anthocyanase. The results show that such measurements are useful (α) in distinguishing O- from C-glycosides, (b) in characterizing flavonoids having sugars attached to more than one hydroxyl group, and (c) for determining suitable conditions for the isolation of intermediate glycosides. Flavonols with glucuronic acid or glucose attached to the 7-hydroxyl are readily distinguished from those having rhamnose attached by their resistance to acid hydrolysis; times for complete hydrolysis are 180, 25 and 5 min respectively. β-Glucosidase attacks the 3-, 7- and 4′-O-glucosides of quercetin at the same rate, but preferentially removes glucose from the 7-hydroxyl group of quercetin 7-glucoside-3-sophoro-side. Anthocyanase hydrolyses anthocyanidin 3-galactosides, 3-glucosides and 3-(diglycosides) much more rapidly than 3-rhamnosides, 3-arabinosides and acylated glycosides.These procedures have been applied, in combination with other methods, to the identification of flavonol glycosides present in species Allium, Helleborus, Lathyrus, Matthiola, Potentilla and Tulipa. New glycosides now characterized are: the 7-glucuronide-3-rutinosides of kaempferol and quercetin, the 7-rhamnoside-3-lathyroside and 7-rhamnoside-3-(rhamnosylarabinoside) of kaempferol, and the 7-glucoside-3-(xylosyl-glucoside), the 3,4′-diglucoside, the 3,7-diglucuronide and the 7-glucoside-3-(caffeoylsophoroside) of quercetin.
• Contains additional discussion and examples on left truncation as well as material on more general censoring and truncation patterns. • Introduces the martingale and counting process formulation swil lbe in a new chapter. • Develops multivariate failure time data in a separate chapter and extends the material on Markov and semi Markov formulations. • Presents new examples and applications of data analysis.
Qualitative identification and quantitative determination of flavonols and flavonesThe method described is suitable for the quantitative determination of flavonols and flavones in plant material and foods. Concentrations of 10 mg/kg fresh weight and higher are determined. The macerated plant material is completely extracted with methanol; the combined extracts are extracted with petroleum ether (b.p. 40–70°) and purified on a polyamide column. Then the glycosides are hydrolysed with I% H2SO4 in methanol and the aglycones formed are identified by thin-layer chromatography. For quantitative determination the hydrolysed extract is carefully applied to cellulose plates in the form of a narrow band and separated in chloroform-formic acid-water (50:45:5). The substances removed can be determined photometrically.ZusammenfassungDie mitgeteilte Methode ermöglicht es, Flavonole und Flavone in Nutzpflanzen und Lebensmitteln in Konzentrationen bis zu 10 mg/1000 g Frischsubstanz exakt quantitativ zu bestimmen. Die zerkleinerten Pflanzenteile werden mit Methanol erschöpfend extrahiert, die Extrakte mit Petroläther (Sdp. 40–70°) ausgezogen und anschliessend mit Hilfe einer Polyamid-Säule gereinigt. Danach erfolgt eine Hydrolyse der Glykoside mit 1%iger methanolischer Schwefelsäure und ein qualitativer dünnschichtchromatographischer Nachweis der enthaltenen Aglykone. Eine für quantitative Arbeiten ausreichende Trennung der Flavon(ol)e wird nach strichförmigem Auftragen auf Cellulose-Platten in Chloroform-Ameisensäure-Wasser (50:45:5) erzielt. Die abgelösten Substanzen können dann photometrisch bestimmt werden.
Quercetin and kaempferol rhamnodiglucosides are characteristic compounds of Camellia sinensis. Their structures were determined as quercetin-and kaempferol-3-O-[β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranosides]. Reversed phase HPLC methods for preparative isolation and analytical separation of both compounds were developed. The structural elucidation of the compounds by means of NMR spectroscopy, fast atom bombardment MS and GC-MS of the sugar moieties is described. Black tea contains 0–0·95 g kg−1 quercetin rhamnodiglucoside and 0·05–1·25 g kg−1 kaempferol rhamnodiglucoside.
THE bracken plant (Pteridium aquilinum) is known to contain radiomimetic
activity. Ingestion by cattle of the whole plant, or of extracts,
produces a syndrome in which there is panmyeloid bone-marrow damage,
pyrexia, and often gut-lining damage and ulceration1; also
typical are the widespread petechial haemorrhages2.
The quercetin and kaempferol contents of eight onion varieties (Allium cepa L.) were determined. The dry skins, outer rings, and inner rings were separated and extracted with methanol to obtain flavonol glycosides that were then hydrolyzed to aglycons. Flavonols were detected and quantified by thin-layer chromatography, high-performance liquid chromatography, and spectrophotometric analyses. The quercetin content of onion tissue decreased from the dry skin to inner rings. The skin of all varieties contained quercetin, both as the aglycon and as glycosides; with some varieties, the skin also contained small amounts of kaempferol. Outer rings of all varieties except Red Hamburger contained small amounts of quercetin while those of Early Yellow Globe, Sweet Spanish Hybrid, and Walla Walla contained small amounts of kaempferol as well. Traces of these flavonols also were detected in the inner rings. The highest quercetin content found in the edible portion of these samples was about 60 mg/kg fresh weight. Small quantities of quercetin and kaempferol were present in scallion leaves but not in bulb tissue. Myricetin was not detected in any sample.
Representative varieties of highbush blueberries, cranberries, and thornless blackberries were compared to determine the extent of differences in the distribution of quercetin, kaempferol, and myricetin. Quantitation was by HPLC using an external standard method. Fruits of four highbush blueberry varieties contained quercetin (24-29 mg/kg, fresh weight) but not kaempferol or myricetin. All three flavonols were found in cranberry fruits, the range for dark-colored fruit of six varieties being 112-250 mg/kg with quercetin, 11-24 mg/kg with myricetin, and 0-3 mg/kg with kaempferol. Within varieties, flavonol contents were smaller in the less highly pigmented berries. Ripe (black-colored) fruits of 12 thornless blackberry varieties and selections contained quercetin (5-35 mg/kg) and kaempferol (1-3 mg/kg). Flavonol and anthocyanin contents were smaller in less ripe fruits. No correlation was seen between the total anthocyanin content and the amounts of flavonols in these cultivars.
The quercetin and kaempferol contents of 13 varieties of lettuce were determined. Leaf lettuce varieties contained 2-54 mg of quercetin/kg, while head lettuce varieties contained 1-28 mg/kg, more in the outer leaves than in the inner leaves. These samples also contained 0-2 mg of kaempferol/kg. Chives contained 55 mg of kaempferol and 9 mg of quercetin per kg in green portions and lesser amounts in white portions, while leek contained 20 mg of kaempferol/kg in green portions and no detectable quercetin in either portion. Two varieties of kale contained 7-20 mg of quercetin and 13-30 mg of kaempferol per kg. Other vegetables examined contained lesser amounts of these flavonols. No myricetin was detected in these samples.
Thirty‐four French red wines originating from six different grape varieties and three different production areas were analysed in duplicate for 15 anthocyanins, ten flavonoids and three colour parameters, F‐statistics, principal component analysis and stepwise discriminant analysis were used to identify and to explain differences among samples.
Clear difference between wines made from different varieties were mainly related to anthocyanin 3‐acylglucosides. Malvidin and peonidin 3‐acetylglucosides were found in increasing concentrations in wines made respectively from Grenache, Carignan, Cinsault, Merlot, Carbernet Sauvignon and Cabernet Franc grapes; the concentrations of peonidin and malvidin 3‐p‐coumarylglucosides were higher in the Cinsault wines studied.
Cabernet Sauvignon and Merlot wines made near Bordeaux had a less intense colour and a higher malvidin 3‐glucoside content than wines from the same varieties produced near Narbonne. Wines made from Merlot, Cabernet Sauvignon and Cabernet Franc grapes contained more catechin, epicatechin and myricetin when produced in the south than in the north (Narbonne, Bordeaux, Angers).
Of the samples analysed, 96%, and all of the nine extra wines, were correctly classified according to the variety of the grapes using four anthocyanins and catechin selected by step wise discriminant analyses.
Low molecular weight phenolic compounds were separated by high performance liquid chromatography on hydrocarbon-bonded reverse phase packings, with a water-methanol elution gradient. Phenolic compounds were extracted from wine with ethyl acetate. A first extraction at pH 7 enabled isolation of neutral molecules (catechins, procyanidins, flavonols, aromatic alcohols); a second extraction at pH 2 was performed to extract phenolic acids. Successive injections of these two extracts in the chromatograph gave the distribution of the different phenolic compounds in the wine under analysis. Analytical data are given for low molecular weight phenolic compounds present in young red Bordeaux wines from different vine cultivars.
The non-volatile, water-soluble constituents of black tea were studied by using reversed-phase HPLC with a photodiode-array detector, using a linear gradient developed for this purpose. The data generated by this detector from one injection of a black tea liquor allowed information on the nature and purity of the constituents to be obtained. The following constituents were identified by the spectral data and the retention times given by reference compounds: caffeine, theobromine, (−)-epicatechin gallate, (−)- epigallocatechin gallate, gallic acid, chlorogenic acid (5-O-caffeoylquinic acid), p-coumaroylquinic acid, quercetin 3-glucoside, quercetin 3-rhamnosylglucoside, kaempferol 3-rhamnosylglucoside, and theaflavin digallate. Other peaks were classified by spectral data, but without reference compounds conclusive assignments could not be made. Finally, a group of peaks could be classified as coloured phenolic pigments, and tentatively assigned as thearubigins.
We studied the effect of quercetin (Q) on the proliferation of HT-29, WiDr, COLO 201, and LS-174T human colon cancer cell lines. Q, between 10 nM and 10 μM, exerted a dose-dependent, reversible inhibition of cell proliferation. Cell-cycle analysis revealed that the growth-inhibitory effect of Q was due to a blocking action in the G0/G1 phase. Using a whole-cell assay with 17β-[3H]-estradiol as tracer, we demonstrated that all these cell lines contain type-II estrogen-binding sites (type-II EBS). By using Q and other chemically related flavonols (3,7-4′-trimethox- yquercetin, 3,7,3,4′-tetramethoxyquercetin, kaempferol, morin, and rutin), we observed that the affinities of these compounds for type-II EBS are correlated with their growth-inhibitory potential. Furthermore, the Q sensitivity of the colon cancer cell lines was correlated with the number of type-II EBS/cell. Then Q could regulate colon cancer cell growth through a binding interaction with type-ll EBS. This mechanism could also be active in vivo as we have observed that cytosolic type-II EBS are present in primary colorectal cancers and that Q is effective in inhibiting the in vitro bromodeoxyuridine incorporated by neoplastic cells in these cancers.
The mutagenicities of 61 flavonoids (naturally occurring flavonoid aglycones and flavonal glycosides and synthetic flavonoids) and those of 11 compounds structurally related to flavonoids were tested with Salmonella typhimurium strains TA100 and TA98. Among the 22 flavone derivatives tested, only wogonin was strongly mutagenic, while five derivatives, apigenin triacetate, acacetin, chrysoeriol, pedalitin, and pedalitin tetraacetate, were only weakly mutagenic. Two bisflavonyl derivatives, neither of which has a 3-hydroxyl group, were not mutagenic. Of the 16 flavonol derivatives tested, all except 3-hydroxyflavone and the tetra- and penta-methyl ethers of quercetin were mutagenic. Of the five flavanone derivatives tested, only 7,4-dihydroxyflavanone was mutagenic, showing weak activity. Of the four flavanonol derivatives tested, hydrorobinetin and taxifolin were weakly mutagenic. Of the six isoflavone derivatives tested, tectorigenin was weakly mutagenic. Of the 11 compounds in the miscellaneous group structurally related to flavonoids, only iso-liquiritigenin was mutagenic, showing weak activity. For the emergence of strong mutagenicity, the double bond between positions 2 and 3 and the hydroxyl group at position 3 are required, except in wogonin, which does not have a hydroxyl group at position 3 but is strongly mutagenic to TA100. The 3-O-acetyl ester of flavonol, quercetin, was mutagenic with S9 mix, but 3-O-methyl ethers were not. Six flavonol glycosides, three quercetin glycosides and three kaempferol glycosides were mutagenic after preincubation with “hesperidinase,” a crude extract of Aspergillus niger. Of 66 flavonoid agylcones and compounds structurally related to flavonoids, quercetin was the strongest mutagen. The carcinogenicity of this compound should be clarified because it is ubiquitously found in vegetables.
Free flavonol aglycones, potentially mutagenic, were determined in vegetable infusions, in fresh and pickled vegetables and in vegetables exposed to mold growth. None of the infusions tested contained any considerable amount of free mutagenic aglycones, but some vegetables, such as red onions and cucumbers, had appreciable amounts of free flavonol aglycones, especially in the external layers. The treatment used in the production of pickled vegetables did not change the quality and quantity of the flavonols but the presence of molds altered the quantity of flavonol aglycones and glycosides.
In this review the qualitative and quantitative occurrence of flavonols and flavones, particularly in fruit and vegetables, are considered. They occur practically in all plants. Their formation normally depends on light so that they are mainly concentrated in the outer tissues. the concentration of flavonols in free standing leaves exceeds that in other parts of the same plant considerably, except in onions.
Flavonols act as antioxidants and protect the ascorbic acid from auto‐oxidation, for example in fruit juices. On the other hand, flavonols can lead to discolourations. Beneficial effects on the human organism have also been described.
Flavonol and flavone glycosides occur in common vegetables, mainly as the quercetin or kaempferol glycosides and less frequently as the luteolin or apigenin glycosides. Their formation normally depends on light, so they are mainly concentrated in the outer tissues. Their concentration in free-standing leaves is considerably greater than that in any other part of the same plant, with the exception of the onion.Flavonol- und Flavon-glykoside kommen in allen Gemsearten vor, hauptschlich als Quercetin- oder Kmpferol- und weniger hufig als Luteolin- oder Apigenin-glykoside. Da ihre Bildung lichtabhngig ist, sind sie im ueren Gewebe angereichert. Die Konzentration ist in freistehenden Blttern mit Ausnahme der Kchenzwiebel erheblich hher als in anderen Teilen der gleichen Pflanze.
The first Dutch National Food Consumption Survey (DNFCS) was conducted in 1987–1988. This report describes the design and methods of the Dutch nutrition surveillance system. The rationale for the use of an existing panel and a two-day record is given, and some potential pitfalls are discussed. The DNFCS data are compared with data from the Dutch national food balance sheets. Data from both individual and household levels are presented and discussed. An example regarding risk group identification is given.
Photosensitized hemolysis of human erythrocytes by hematoporphyrin was suppressed by flavonols such as quercetin and rutin at submillimolar concentrations. The suppression of photohemolysis was accompanied by inhibition of lipid peroxidation by the reagents. Quercetin and rutin were photooxidized in the presence of hematoporphyrin and the photooxidation was partially suppressed by 1 mM NaN3, a quencher of singlet molecular oxygen. Flavonols were also oxidized by radicals formed during degradation of lauroyl peroxide. These results indicate that flavonols can function as antioxidants in biological systems by terminating radical chain reactions and removing singlet molecular oxygen. A pharmacological function of flavonols, decrease of the increased permeability and gragility of capillary, was discussed in relation to their antioxidative functions.
A rapid method based on RP-HPLC with UV detection is presented for the quantitative determination of five major flavonoid aglycons, viz. quercetin, kaempferol, myricetin, luteolin, and apigenin, in freeze-dried vegetables and fruits, after acid hydrolysis of the parent glycosides. Completeness of hydrolysis and extraction have been optimized by testing systematically different conditions such as acid concentration, reaction period, and methanol concentration in the extraction solution using samples containing various types of flavonoid glycosides. Optimum hydrolysis conditions are presented for flavonol glucuronides, flavonol glucosides, and flavone glycosides. Identity of the flavonoids was confirmed with diode array. Repeatability of the method was good, with coefficients of variation of 2.5-3.1 % for quercetin, 4.6-5.6 % for kaempferol, 4.6 % for myricetin, 3.3 % for luteolin, and 2.8 % for apigenin. CV of the within-laboratory reproducibility was less than 2 times the CV of repeatability. Recoveries of the flavonols quercetin, kaempferol, and myricetin ranged from 77 to 110 %, and recoveries of the flavones apigenin and luteolin ranged from 99 to 106 %. The method presented allows a fast, quantitative, and reproducible determination of five flavonoids in freeze-dried foods.
The content of the potentially anticarcinogenic flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin of commonly consumed beverages was determined by RP-HPLC with UV detection. Flavonoid levels in beer, coffee, chocolate milk, and white wine were below 1 mg/L. Twelve types of tea infusion, six types of wine, apple juice, tomato juice, grape juice, orange juice, grapefruit juice, and lemon juice were analyzed. No luteolin or apigenin were detected in any of the beverages. In red wines and in grape juice quercetin and myricetin levels varying from 4 to 16 mg/L and from 7 to 9 mg/L, respectively, were detected. Quercetin levels in fruit juices were generally below 5 mg/L except for lemon juice (7 mg/L) and tomato juice (13 mg/L). In black tea infusions quercetin (10-25 mg/L), kaempferol (7-17 mg/L), and myricetin (2-5 mg/L) were detected. Flavonoid levels in green tea were comparable to those in black tea. The flavonoid content of tea prepared with tea bags was generally higher than that of tea prepared with loose leaves. Together with data on the flavonoid content of vegetables and fruits published previously (Hertog et al. J. Agric. Food Chem. 1992, 40, 2379-2383), these data provide a base for an epidemiological evaluation of the potentially anticarcinogenic effects of flavonoids.
The mutagenic activities of several flavonoids and flavonoid metabolites were examined by means of Salmonella typhimurium mutants that reveal base-pair substitution and frameshift mutagens. Of the compounds tested (naringin, rutin, neohesperetin, hesperetin, dihydroquercetin, quercetin, quercetin pentaacetate, permethylquercetin, m-hydroxyphenylacetic acid, and m,p-dihydroxyphenylacetic acid), only quercetin was mutagenic without microsomal activation. With activation, however, the mutagenic activity of quercetin was increased significantly and that of quercetin pentaacetate was revealed. The health implications of these findings and aspects of flavonoid structural requirements for mutagenic activity are discussed.
Indole-3-carbinol, 3,3'-diindolylmethane, and indole-3-acetonitrile, three indoles occurring in edible cruciferous vegetables, have been studied for their effects on 7,12-dimethylbenz(a)anthracene-induced mammary tumor formation in female Sprague-Dawley rats and on benzo(a)pyrene-induced neoplasia of the forestomach in female ICR/Ha mice. When given by p.o. intubation 20 hr prior to 7,12-dimethylbenz(a)anthracene administration, indole-3-carbinol and 3,3'-diindolylmethane had an inhibitory effect on mammary tumor formation, but indole-3-acetonitrile was inactive. Indole-3-carbinol when added to the diet for 8 days prior to challenge with 7,12-dimethylbenz(a)anthracene inhibited mammary tumor formation, whereas indole-3-acetonitrile did not. Dietary administration of all three indoles inhibited benzo(a)pyrene-induced neoplasia of the forestomach in ICR/Ha mice. The identification of dietary constituents that can inhibit chemical carcinogens ultimately may be of value in understanding the balance of factors that determines the neoplastic response to these cancer-producing agents in the environment.
The pharmacokinetics of quercetin, a flavonoid, have been studied in 6 volunteers after single intravenous (100 mg) and oral (4 g) doses. The data after iv administration were analyzed according to a two compartment open model with half lives of 8.8 +/- 1.2 min for the alpha phase and 2.4 +/- 0.2 h for the beta phase (predominant half life), respectively. Protein binding was greater than 98%. The apparent volume of distribution was small at 0.34 +/- 0.03 1/kg. Of the intravenous dose 7.4 +/- 1.2% was excreted in urine as a conjugated metabolite, and 0.65 +/- 0.1% was excreted unchanged. After oral administration no measurable plasma concentrations could be detected, nor was any quercetin found in urine, either unchanged or in a metabolized form. These results exclude absorption of more than 1% of unchanged drug. Recovery in faeces after the oral dose was 53 +/- 5%, which suggests extensive degradation by microorganisms in the gut. The data obtained show that oral administration of flavonoids may be of questionable value.
Oxidative modification of LDL renders it immunogenic and autoantibodies to epitopes of oxidised LDL, such as malondialdehyde (MDA)-lysine, are found in serum and recognise material in atheromatous tissue. However, there has been no prospective study to assess the importance of oxidised LDL among patients with vascular disease. We compared the titre of autoantibodies to MDA-modified LDL and native LDL in baseline serum samples of 30 eastern Finnish men with accelerated two-year progression of carotid atherosclerosis and 30 age-matched controls without progression. Neither group had specific antibody binding to native LDL. A titre was defined as a ratio of antibody binding to MDA-LDL/binding to native LDL. Cases had a significantly higher titre to MDA-LDL (2.67 vs 2.06, p = 0.003). Cases also had a greater proportion of smokers (37% vs 3%), higher LDL cholesterol (4.2 mmol/l vs 3.6 mmol/l), and higher serum copper concentration (1.14 mg/l vs 1.04 mg/l). Even after adjusting for these variables and the severity of baseline atherosclerosis, the difference in antibody titre remained significant in a multifactorial logistic model (p = 0.031). Thus, the titre of autoantibodies to MDA-LDL was an independent predictor of the progression of carotid atherosclerosis in these Finnish men. Our data provide further support for a role of oxidatively modified LDL in atherogenesis.
Recently, we and others showed that the components of green tea may be useful cancer chemopreventive agents. It has been suggested that (-)-epigallocatechin-3-gallate (EGCG), the major constituent in green tea, may possess antitumor-promoting and/or anticarcinogenic effects in rodent tumor bioassay systems. During the chemical analysis of various green tea products, we found a traditionally preserved preparation of green tea used by tribes in the Himalayan region of Sikkim, India that was rich in EGCG. EGCG was isolated from this tea product, and its inhibitory effects were evaluated against the binding of topically applied 3H-labeled polycyclic aromatic hydrocarbons (PAHs) to epidermal DNA and 12-O-tetradecanoylphorbol-13-acetate (TPA) caused induction of epidermal ornithine decarboxylase (ODC) activity in Sencar mice, the short-term markers of tumor initiation and tumor promotion, respectively. Preapplication of EGCG resulted in significant inhibition (p less than 0.05) in the binding of [3H]PAH to epidermal DNA. Similarly, the topical application of EGCG resulted in significant inhibition (p less than 0.005) in TPA-caused induction of epidermal ODC activity. In further studies, we assessed the anti-skin tumor-initiating effect of EGCG in Sencar mice in an initiation-promotion protocol. The application of EGCG before challenge with 7,12-dimethylbenz[a]anthracene as tumor initiator resulted in significant reduction both in percentage of mice with tumors and number of tumors per mouse compared with a non-EGCG-pretreated group of animals. The results of the present study suggest that the green tea preparation from Sikkim may be a good source for the isolation of EGCG and that this compound may have significant potential as a cancer chemopreventive agent.
No doubt can remain that the flavonoids have profound effects on the function of immune and inflammatory cells as determined by a large number and variety of in vitro and some in vivo observations. That these ubiquitous dietary chemicals may have significant in vivo effects on homeostasis within the immune system and on the behavior of secondary cell systems comprising the inflammatory response seems highly likely but more work is required to strengthen this hypothesis. Ample evidence indicates that selected flavonoids, depending on structure, can affect (usually inhibit) secretory processes, mitogenesis, and cell-cell interactions including possible effects on adhesion molecule expression and function. The possible action of flavonoids on the function of cytoskeletal elements is suggested by their effects on secretory processes. Moreover, evidence indicates that certain flavonoids may affect gene expression and the elaboration and effects of cytokines and cytokine receptors. How all of these effects are mediated is not yet clear but one important mechanism may be the capacity of flavonoids to stimulate or inhibit protein phosphorylation and thereby regulate cell function. Perhaps the counterbalancing effect of cellular protein tyrosine phosphatases will also be found to be affected by flavonoids. Some flavonoid effects can certainly be attributed to their recognized antioxidant and radical scavenging properties. A potential mechanism of action that requires scrutiny, particularly in relation to enzyme inhibition, is the redox activity of appropriately configured flavonoids. Finally, in a number of cell systems it seems that resting cells are not affected significantly by flavonoids but once a cell becomes activated by a physiological stimulus a flavonoid-sensitive substance is generated and interaction of flavonoids with that substance dramatically alters the outcome of the activation process.
The relationship between tea consumption and cancer risk has been analyzed using data from an integrated series of case-control studies conducted in northern Italy between 1983 and 1990. The dataset included 119 histologically confirmed cancers of the oral cavity and pharynx, 294 of the esophagus, 564 of the stomach, 673 of the colon, 406 of the rectum, 258 of the liver, 41 of the gallbladder, 303 of the pancreas, 149 of the larynx, 2,860 of the breast, 567 of the endometrium, 742 of the ovary, 107 of the prostate, 365 of the bladder, 147 of the kidney, 120 of the thyroid, and a total of 6,147 controls admitted to hospital for acute nonneoplastic conditions unrelated to long-term dietary modifications. Multivariate relative risks (RR) for tea consumption were derived after allowance for age, sex, area of residence, education, smoking, and coffee consumption. All the estimates for tea consumption were close to unity, the highest values being 1.4 for rectum, gallbladder, and endometrium. There was no association with cancers of the oral cavity (RR = 0.6), esophagus (RR = 1.0), stomach (RR = 1.0), bladder (RR = 0.8), kidney (RR = 1.1), prostate (RR = 0.9), or any other site considered. Although in northern Italy tea was consumed daily by only a limited proportion of the population, this integrated series of studies offers further reassuring evidence on the relationship between tea and cancer risk.