[Show abstract][Hide abstract] ABSTRACT: Tea (Camellia sinensis L.) is a perennial woody plant that is widely cultivated to produce a popular non-alcoholic beverage; this beverage has received much attention due to its pleasant flavor and bioactive ingredients, particularly several important secondary metabolites. Due to the significant changes in the metabolite contents of the buds and the young expanding leaves of tea plants, high-performance liquid chromatography (HPLC) analysis and isobaric tags for relative and absolute quantitation (iTRAQ) analysis were performed. A total of 233 differentially expressed proteins were identified. Among these, 116 proteins were up-regulated and 117 proteins were down-regulated in the young expanding leaves compared with the buds. A large array of diverse functions was revealed, including roles in energy and carbohydrate metabolism, secondary metabolite metabolism, nucleic acid and protein metabolism, and photosynthesis- and defense-related processes. These results suggest that polyphenol biosynthesis- and photosynthesis-related proteins regulate the secondary metabolite content of tea plants. The energy and antioxidant metabolism-related proteins may promote tea leaf development. However, reverse transcription quantitative real-time PCR (RT-qPCR) showed that the protein expression levels were not well correlated with the gene expression levels. These findings improve our understanding of the molecular mechanism of the changes in the metabolite content of the buds and the young expanding leaves of tea plants.
Full-text · Article · Jun 2015 · International Journal of Molecular Sciences
[Show abstract][Hide abstract] ABSTRACT: The present study examined the effects of black tea (Camellia sinensis) extracts (BTE) in Caenorhabditis elegans under various abiotic stressors. Results showed BTE increased nematode resistance to osmosis, heat, and UV irradiation treatments. However, BTE could not increase nematodes' lifespan under normal culture conditions and MnCl2-induced toxicity at concentrations we used. Further studies showed that BTE decreased reactive oxygen species and up-regulated some antioxidant enzymes, including GSH-PX, and genes, such as gsh-px and sod-3. However, only a slight extension in mev-1 mutants mean lifespan was observed without significance. These result indicated that antioxidant activity of BTE might be necessary but not sufficient to protect against aging to C.elegans. Moreover, BTE increased mRNA level of stress-response genes like sir-2.1 and sek-1. Our finding demonstrated BTE might increase heat and UV stress resistance in a sir.2.1-dependent manner. Taken together, BTE enhanced stress resistance with multiple mechanisms in C.elegans.
Full-text · Article · Oct 2014 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: Theaflavins (TF), thearubigins (TR) and theabrownins (TB) are the major polyphenols that determine the quality of black tea. These compounds were measured in black teas and their correlation with taste values and taste quality was investigated. TF, TR and TB in the black teas from Chinese markets averaged 0.24%, 4.07% and 7.59%, respectively. Correlation analysis showed that TF was positively and significantly correlated with astringency (r = 0.521, p < 0.05), aftertaste of astringency (r = 0.619, p < 0.01) and richness (r = 0.618, p < 0.01). TR was also positively correlated aftertaste of astringency (r = 0.530, p < 0.05), while TB was negatively correlated with bitterness (r = -0.486, p < 0.05). Taste score had a positive correlation with TF (r = 0.691, p < 0.01) and TR (r = 0.604, p < 0.05). Meanwhile, taste score correlated positively with astringency (r = 0.483, p < 0.05) and aftertaste of astringency (r = 0.518, p < 0.05). The result showed that black teas can be partially classified by cluster analysis using PCA components.
No preview · Article · May 2014 · Food Science and Technology Research
[Show abstract][Hide abstract] ABSTRACT: Adventitious root (AR) formation is a critical process for plant clonal propagation. The role of plant secondary metabolites in AR formation is still poorly understood. Chemical and physical mutagenesis in combination with somatic variation were performed on Artemisia annua in order to obtain a mutant with changes in adventitious rooting and composition of plant secondary metabolites. Metabolic and morphological analyses of the increased adventitious rooting (iar) mutant coupled with in vitro assays were used to elucidate the relationship between plant secondary metabolites and AR formation. The only detected differences between the iar mutant and wild-type were rooting capacity and borneol/camphor content. Consistent with this, treatment with borneol in vitro promoted adventitious rooting in wild type. The enhanced rooting did not continue upon removal of borneol. The iar mutant displayed no significant differences in AR formation upon treatment with camphor. Together, our results suggest that borneol promotes adventitious rooting whereas camphor has no effect on AR formation.
No preview · Article · Dec 2013 · Physiologia Plantarum
[Show abstract][Hide abstract] ABSTRACT: Renal accumulation of reactive carbonyl compounds (RCCs) has been linked to the progression of diabetic nephropathy. We previously demonstrated that carbonyl stress induces the formation of amino-carbonyl cross-links and sharply increases the content of β-sheet-rich structures, which is the seed of insoluble aggregates formation, and tea catechin (-)-epigallocatechin 3-gallate (EGCG) can reverse this process in vitro and in vivo. In this study, methylated derivative (-)-epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG3"Me) was hypothesized to neutralize carbonyl stress mediating the formation of insoluble ubiquitinated protein (IUP) aggregates, and reduce the early development of diabetic nephropathy.
Diabetes was induced in mice by intraperitoneally injecting alloxan monohydrate (200 mg/kg/d) twice and administering EGCG3"Me by gavage for 15 d. Reagent case and western blot results showed that, in diabetic kidneys, the carbonyl proteins in the serum increased; and in insoluble protein fraction, 4-hydroxynonenal-modified proteins, IUP aggregates and p62 accumulated; FT-IR study demonstrated that the lipid content, anti-parallel β-sheet structure and aggregates increased. EGCG3"Me treatment could effectively reverse this process, even better than the negative control treatment.
EGCG3"Me exhibiting anti-β-sheet-rich IUP aggregate properties, maybe represents a new strategy to impede the progression of diabetic nephropathy and other diabetic complications.
[Show abstract][Hide abstract] ABSTRACT: (-)-Epigallocatechin-3-gallate (EGCG), the most abundant catechin found in green tea, effectively reduces body weight and tissue and blood lipid accumulation. To explore the mechanism by which EGCG inhibits cellular lipid accumulation in free fatty acid (FFA) induced HepG2 cell culture, we investigated the proteome change of FFA-induced HepG2 cells exposed to EGCG using two-dimensional gel electrophoresis and mass spectrometry.
In this study, 36 protein spots showed a significant change in intensity by more than 1.5-fold from the control group to the FFA group and from the FFA group to the FFA + EGCG group. Among them, 24 spots were excised from gels and identified by LC-MS/MS. In total, 18 proteins were successfully identified. All identified proteins were involved in lipid metabolism, glycometabolism, antioxidant defense, respiration, cytoskeleton organization, signal transduction, DNA repair, mRNA processing, iron storage, or were chaperone proteins. This indicated that these physiological processes may play roles in the mechanism of inhibition of lipid accumulation by EGCG in FFA-induced HepG2 cells. Western blotting analysis was used to verify the expression levels of differentially expressed proteins, which agree with the proteomic results.
From the proteomic analysis, we hypothesized that EGCG reduced cellular lipid accumulation in FFA-induced HepG2 cells through the activation of AMP-activated protein kinase (AMPK) resulting from the generation of reactive oxygen species (ROS). The induction of ROS may be a result of EGCG regulation of the antioxidant defense system. Activation of AMPK shifted some FFA toward oxidation, away from lipid and triglyceride storage, and suppressed hepatic gluconeogenesis. The findings of this study improve our understanding of the molecular mechanisms of inhibition of lipid accumulation by EGCG in HepG2 cells.
[Show abstract][Hide abstract] ABSTRACT: Background:
Fuzhuan brick tea is a kind of microbial fermented tea, which has received increasing attention in recent years owing to its benefits for human health. In this study, the anti-obesity and hypolipidemic effects of Fuzhuan brick tea water extracts (FTEs) were investigated.
FTEs consisted of 204.07 ± 3.38 mg g(-1) polyphenol, 109.20 ± 1.36 mg g(-1) flavonoids, and others. The FTEs significantly suppressed the increase of body weight and accumulation of adipose tissue, and reduced the level of serum triacylglycerol, total cholesterol and low-density lipoprotein (LDL) cholesterol in obese rats fed a high-fat diet. Moreover, FTEs attenuated the gene expression of sterol regulatory element binding protein-1c, fatty acid synthase and CCAAT/enhancer binding protein α, which is related to lipogenic metabolism. In contrast, the gene expressions of enzymes involved in energy expenditure and lipodieresis including hepatic peroxisome proliferator-activated receptor α, carnitine palmitoyltransferase 1a and LDL receptor gene expression were increased by FTE treatment.
Our study demonstrates that FTEs have anti-obesity and hypolipidemic functions, suggesting that it might be effective for treatment of obesity and hyperlipemia.
Full-text · Article · Apr 2013 · Journal of the Science of Food and Agriculture
[Show abstract][Hide abstract] ABSTRACT: It is still a major challenge to simultaneously isolate artemisinin and its precursors, especially dihydroartemisinic acid and artemisinic acid, from herbal Artemisia annua. A rapid, economical and automatical chromatographic separation process to isolate and purify artemisinin, dihydroartemisinic acid and artemisinic acid at the same time on a preparative scale was developed. The procedure included solvent extraction of ground Artemisia annua leaves by refluxing and purification of crude extract by preparative reverse-phase high-performance liquid chromatography (RP-HPLC). Fractions containing artemisinin and its precursors were collected and identified by gas chromatography and mass spectrometry. High purity of artemisinin, dihydroartemisinic acid and artemisinic acid was obtained by preparative HPLC with a C(18) column and 60% acetonitrile in water as the mobile phase. The techniques described here are useful tools for the preparative-scale isolation of artemisinin and its precursors in a fast, cost-effective and environmental friendly manner.
No preview · Article · Jun 2012 · Biomedical Chromatography
[Show abstract][Hide abstract] ABSTRACT: The growth inhibition and cytotoxic effects of theaflavins mixture and pure theaflavins [theaflavin, theaflavins-3-gallate, theaflavins-3′-gallate and theaflavin-3, 3′-digallate] from black tea on human liver cancer HepG2 cells, gastric cancer SGC-7901 cells, lung cancer A549 cells and acute promyelocytic leukemia K562 cells were investigated. The four major theaflavins were obtained from enzymatically oxidized catechins mixture using preparative high-performance liquid chromatography (HPLC). The purity and the structures of the isolated compounds were confirmed by 1H nuclear magnetic resonance, Liquid chromatography-mass spectrometry (LC/MS), Fourier-transform infrared, HPLC with diode array detection and thin-layer chromatography analyses. Theaflavin monomers and mixture exhibited strong inhibitory effects on SGC-7901 and A549 cells. The obtained TF2A exhibited high inhibition activity against the growth of all four cancer cells examined. It is concluded that individual theaflavins have differential inhibitory activity in cancer cell lines and that TF2A have promising activity to be considered in anticancer treatment research as a drug or a template for drug synthesis.
Theaflavins have received much attention because of their potential benefits for human health. In this study, we used a modified method for the preparation and isolation of theaflavins and examined the cytotoxic activity of the individual theaflavins against human liver cancer (HepG2) cells, gastric cancer (SGC-7901) cells, lung cancer (A549) cells and acute promyelocytic leukemia (K562) cells. Our results demonstrates that individual theaflavins have differential inhibitory activity in cancer cell lines and has the potential to be used individually for functional food applications and for therapy targeting specific cancer treatments. The most active theaflavin (TF2A) is a promising compound that can be used as a drug or a template for drug synthesis for anticancer research.
No preview · Article · Dec 2011 · Journal of Food Biochemistry
[Show abstract][Hide abstract] ABSTRACT: Emerging evidence supports health-promoting properties of post-fermented Chinese Brick Tea. Fu Zhuan Tea, fermented with the fungus, Erotium cristatum, contains a unique phytochemical profile attributed to its unique method of processing. Fu Zhuan Tea has been shown to activate pancreatic enzymes and regulate blood lipids in laboratory models. Regulation of blood lipid levels by Fu Zhuan Tea consumption was examined in an observational pilot study of volunteers with elevated LDL cholesterol that were not taking any prescription lipid lowering medications. Significant changes in blood lipids were detected after 120 days of daily consumption. Fu Zhuan Tea fractionation led to the investigation of six compounds for regulation of transcription factors involved in lipid metabolism, including Farnesoid X receptor (FXR), Liver X-activated Receptor (LXR) and two isoforms of the Peroxisome Proliferator-Activated Receptors (PPARγ and PPARδ). Reporter gene assays with liver cells revealed dose dependent differences in regulation of transcription factor activation. These data reveal potential therapeutic efficacy and candidate molecular targets for Fu Zhuan Tea, and provide rationale for chemical characterization of bioactive fractions and investigation of therapeutic efficacy in cardiovascular disease and type 2 diabetes.
Full-text · Article · Nov 2011 · Food Research International
[Show abstract][Hide abstract] ABSTRACT: Lipofuscin age pigment is often considered as a hallmark of aging, which shows an accumulation rate inversely correlated with longevity and it is primarily composed of carbonyl-amino cross linked protein residues. The purpose of this study is to determine whether epigallocatechin gallate (EGCG) would inhibit the formation of age pigment in both MDA-modified human serum albumin and D-galactose-induced aging mice models by using spectrofluorometry, HPLC-PDA, FTIR spectrometer, SEM and TEM observation. Results showed that EGCG could inhibit the formation of age pigment in vitro and in vivo. The structure-activity relationship suggested that besides anti-oxidative stress and trapping the reactive unsaturated aldehydes, the inhibiting effects were correlated with the galloyl D-ring of tea catechins on neutralizing the amino-carbonyl cross-linking reaction.
No preview · Article · Oct 2011 · Journal of medicinal plant research
[Show abstract][Hide abstract] ABSTRACT: White leaf No.1 is a typical albino tea cultivar grown in China and it has received increased attention in recent years due to the fact that white leaves containing a high level of amino acids, which are very important components affecting the quality of tea drink. According to the color of its leaves, the development of this tea cultivar is divided into three stages: the pre-albinistic stage, the albinistic stage and the regreening stage. To understand the intricate mechanism of periodic albinism, a comparative proteomic approach based on two-dimensional electrophoresis (2-DE) and mass spectrometry was adopted first time to identify proteins that changed in abundance during the three developmental periods.
The 2-DE results showed that the expression level of 61 protein spots varied markedly during the three developmental stages. To analyze the functions of the significantly differentially expressed protein spots, 30 spots were excised from gels and analyzed by matrix-assisted laser desorption ionization-time of flight-tandem mass spectrometry. Of these, 26 spots were successfully identified. All identified protein spots were involved in metabolism of carbon, nitrogen and sulfur, photosynthesis, protein processing, stress defense and RNA processing, indicating these physiological processes may play crucial roles in the periodic albinism. Quantitative real-time RT-PCR analysis was used to assess the transcriptional level of differentially expressed proteins. In addition, the ultrastructural studies revealed that the etioplast-chloroplast transition in the leaf cell of White leaf No. 1 was inhibited and the grana in the chloroplast was destroyed at the albinistic stage.
In this work, the proteomic analysis revealed that some proteins may have important roles in the molecular events involved in periodic albinism of White leaf No. 1 and identificated many attractive candidates for further investigation. In addition, the ultrastructural studies revealed that the change in leaf color of White leaf No. 1 might be a consequence of suppression of the etioplast-chloroplast transition and damage to grana in the chloroplast induced by temperature. These results provide much useful information to improve our understanding of the mechanism of albinism in the albino tea cultivar.
[Show abstract][Hide abstract] ABSTRACT: As tea is one of the most popular beverages consumed worldwide, it is important for customers and business investigators to develop an easy and reliable method to discriminate between different types of teas from each other. A total of eighty-seven types of various white, green, oolong, black and Puer teas were collected from the major tea estates in China, and their catechin contents and volatile compounds were compared by high performance liquid chromatograph and gas chromatograph mass spectrometer. It was found green tea contained the highest concentrations of total catechins, (−)-epicatechin gallate (ECG) and (−)-epigallocatechin gallate (EGCG), while oolong teas contained the highest concentrations of (−)-epigallocatechin (EGC) among these five types of teas. The aroma composition and their quantities in different types of teas varied quite widely. The concentration of ECG, EGCG, pentanal, hexanal, methyl jasmonate, indole, (E,E)-2,4-hexadienal and 1,2,3-trimethoxybenzene was shown to be different and could be used to discriminate white, green, oolong, black and Puer teas. The result showed that different types of teas could be partially classified by cluster analysis using index of individual catechins and volatile components.
No preview · Article · Apr 2011 · International Journal of Food Science & Technology
[Show abstract][Hide abstract] ABSTRACT: The present study describes a rapid and sensitive HPLC method for the quantification of huperzine A (HupA) in Huperzia crispata (Huperziaceae). The sample extraction and preparation involved a simple, time-saving, single-solvent extraction, with each sample being analyzed within 12 min. The mobile phase was ammonium acetate (0.1 M, pH 6.0)--methanol (64 + 36, v/v) at a flow rate of 1.0 mL/min. Detection was at 308 nm. The calibration curve was linear from 0.049 to 7.84 microg (R2 = 0.9997), with intraday and interday precision RSD of less than 2%. The extraction recovery rate was over 98.49%. Quantification of HupA was performed using this modified method, and the content of HupA was 1.86 times higher in the whole plant of H. crispata (218.17 +/- 1.55 microg/g) than in that of H. serrata (117.03 +/- 2.97 microg/g). In the whole plant of H. crispata, HupA mainly accumulated in the actively growing shoot tips, the apical bud, and the 10 youngest leaves, reaching 455.23 +/- 2.97 microg/g. The content of HupA in the samples from sunshine-sheltered sites was 3.45 times higher than in that from sunshine-abundant sites. The satisfactory results indicate that this modified method can be applied in the quality control of large-scale Huperziaceae plant extracts and that changes should be made in the cultivation of H. crispata so as to maximize the production of HupA.
No preview · Article · Sep 2010 · Journal of AOAC International
[Show abstract][Hide abstract] ABSTRACT: In order to estimate landmark direction angle to localize robot in an artificial environment based on omnidirectional image, this paper introduces the method about low pass filter noise elimination, artificial landmark features detection and landmark direction angle estimation algorithms. Landmark feature detection proposed that red landmark pixels beyond the threshold were extracted as a small area and the center of gravity was calculated for the extracted small area representing the candidate of one landmark. The blue patch provides as compensation to further distinguish the landmark from other objects in a complex environment. Two type experiments were done. The landmark detection experiment proved that the low-pass filter noise elimination was effective. Another experiment was conducted on the level cement ground in a 5×5-m area in the sunlight. 16 test positions were chose to test. Results showed that the MAE and RMSE of landmark direction angles were 1.12 degree and 1.30 degree, respectively. The proposed direction angle estimation method is high accuracy, low time-consuming computation and good robustness.
[Show abstract][Hide abstract] ABSTRACT: Properties of leaf and infusion colours, chemical components and volatile flavour compounds of oolong teas and their correlation with perceived quality score given by tea-tasting panel were analysed. The scores for appearance and infused leaf correlated strongly with concentrations of chlorophyll a (chl a), chlorophyll (chl b) and chlorophyll (chl) (r = 0.355–0.433, P < 0.05) and the total quality score (TQS) positively correlated with concentrations of chl a, chl b and chl (r = 0.517–0.533, P < 0.01). The perceived taste score and TQS positively correlated with the concentration of total free amino acid (r = 0.514, 0.694, P < 0.01) and theanine (r = 0.500, 0.684, P < 0.01). The volatile composition and their quantities varied widely among oolong tea samples. Nerolidol, indole, benzeneacetaldehyde, linalool, linalool oxide I, hexanal, benzyl nitrile, geraniol and 1-penten-3-ol were prevailing volatile compounds detected in most of oolong tea samples. Principal component analysis screened ten principal components with the first three (glutamic acid, total catechins and benzeneacetaldehyde) explaining 27.86%, 20.00% and 14.46% of the total variance, respectively. Regression analysis upon the ten principal components formulated a prediction model on the total quality score with 78.5% probability. The result showed that oolong teas could be partially classified by cluster analysis based on principal components.
Full-text · Article · Apr 2010 · International Journal of Food Science & Technology
[Show abstract][Hide abstract] ABSTRACT: Malaria threatens 300-500 million people and kills more than one million people annually. Artemisinin has been widely used as part of the artemisinin-based combination therapies against malaria. However, its supply is seriously short due to very small amounts of production of artemisinin in Artemisia annua. Molecular biologic researches aimed at increasing the artemisinin yield in plant have received more and more attention and therefore corresponding quantification methods for artemisinin analysis are urgently needed. A variety of methods for determination of artemisinin have been developed but they cannot be applied when only very little plant material is available or the material should be kept live, which often occurs in molecular biologic researches. The present work developed a simple, fast and low toxic micro-scale analysis procedure for determination of artemisinin in a single leaf or flower of living Artemisia annua using improved gas chromatography with electron-capture detection. The recovery of >95% was achieved by vortex of a piece of fresh leaf in 1 mL ethyl acetate for 2 min at room temperature. This method provides a powerful tool for biosynthesis study of artemisnin, high-throughput screening high-yield clone in an early stage, or real-time quality control of Artemisia annua crop.
Full-text · Article · Oct 2009 · Biomedical Chromatography
[Show abstract][Hide abstract] ABSTRACT: Malaria is a global health problem that threatens 300-500 million people and kills more than one million people annually. Artemisinin is highly effective against multidrug-resistant Plasmodium falciparum and it has been widely used as part of the artemisinin-based combination therapies against malaria. To elucidate the biosynthetic pathway of artemisinin and to clone related genes in Artemisia annua, differentially expressed genes between blooming flowers and flower buds were isolated and characterized by a combined approach of suppression subtractive hybridization (SSH) and metabolite analysis. A total of 350 cDNA clones from a subtractive cDNA library were randomly picked, sequenced and analyzed and 253 high-quality sequences were obtained. BLASTX comparisons indicated that about 9.9 % of the clones encoded enzymes involved in isoprenoid (including artemisinin) biosynthesis. The expression of 4 gene transcripts involved in artemisinin biosynthesis was examined by RT-PCR and the results confirmed the higher expression of these transcripts in blooming flowers than in flower buds. In addition, 2 putative transcript factors transparenta testa glabra 1 (TTG1) and ENHANCER OF GLABRA3 (GL3), which promote trichome initiation, were presented in the library. Finally, this study demonstrated that the increase of expression level of the putative TTG1 gene correlated with the improvement of glandular trichome density and artemisinin production in A. annua leaves. The subtractive cDNA library described in the present study provides important candidate genes for future research in order to increase the artemisinin content in A. annua.
[Show abstract][Hide abstract] ABSTRACT: Artemisinin demand has increased sharply since the World Health Organization recommended its use as part of the artemisinin combination therapies in 2001. The area for the crop cultivation has expanded in Africa and Asia and simpler and affordable methods for artemisinin analysis are needed for crop quality control. This work presented a novel chromatographic method of artemisinin analysis using gas chromatography with electron-capture detection. The sample extraction and preparation involved a single-solvent one-step extraction, with samples being analyzed in the extraction solvent directly after extraction. This method was accurate and reproducible with over 97% recoveries. The limit of detection was less than 3 microg/mL and the limit of quantification was less than 9 microg/mL, allowing samples as low as 100mg dry weight to be analyzed for artemisinin. The method can be applied to quality control of commercial plant extracts and to artemisinin-derived pharmaceuticals.
Full-text · Article · Jun 2008 · Journal of Chromatography A