Physicochemical properties and antibacterial mechanism of theabrownins prepared from different catechins catalyzed by polyphenol oxidase and peroxidase

Theabrownins(TBs)are the characteristic functional and quality components of dark teas such as Pu’er tea and Chin-brick tea.TBs are a class of water-soluble brown polymers with multi-molecular weight distribution produced by the oxidative polymerisation of tea polyphenols during the fermentation process of dark tea,both enzymatically and non-enzymatically.TBs have been extracted and purified from dark tea all the time,but the obtained TBs contain heterogeneous components such as polysaccharides and caffeine in the bound state,which are difficult to remove.The isolation and purification process was tedious and required the use of organic solvents,which made it difficult to industrialise TBs.In this study,epigallocatechin(EGC),epigallocatechin gallate(EGCG),epigallocatechin gallate(ECG),EGC/EGCG(mass ratio 1:1),EGCG/ECG(mass ratio 1:1),EGC/ECG(mass ratio 1:1)and EGC/EGCG/ECG(mass ratio 1:1:1)as substrates and catalyzed by polyphenol oxidase(PPO)and peroxidase(POD)in turn to produce TBs,named TBs-dE-1,TBs-dE-2,TBs-dE-3,TBs-dE-4,TBs-dE-5,TBs-dE-6 and TBs-dE-7.The physicochemical properties and the antibacterial activity and mechanism of TBs-dE-1–7 were investigated.Sensory and colour difference measurements showed that all seven tea browning samples showed varying degrees of brownish hue.Zeta potential in aqueous solutions at pH 3.0–9.0 indicated that TBs-dE-1–7 was negatively charged and the potential increased with increasing pH.The characteristic absorption peaks of TBs-dE-1–7 were observed at 208 and 274 nm by UV-visible(UV-vis)scanning spectroscopy.Fourier transform infrared(FT-IR)spectra indicated that they were phenolic compounds.TBs-dE-1–7 showed significant inhibition of Escherichia coli DH5α(E.coli DH5α).TBs-dE-3 showed the strongest inhibitory effect with minimum inhibitory concentration(MIC)of 1.25 mg mL–1 and MBC of 10 mg mL–1,followed by TBs-dE-5 and TBs-dE-6.These three TBs-dEs were selected to further investigate their inhibition mechanism.The TBs-dE was found to damage the extracellular membrane of E.coli DH5α,causing leakage of contents,and increase intracellular reactive oxygen content,resulting in abnormal cell metabolism due to oxidative stress.The results of the study provide a theoretical basis for the industrial preparation and product development of TBs.

Influence of Tea Leaf Particle Size on Catechin Extraction and Green Tea Sensory Acceptance

The intensity of the bitterness of catechins increases with increased concentration, but the taste palatability decreased in green tea extract. The aim of this study was to investigate whether a blend of tea leaf particles of various sizes would result in a good balance between catechin content and appreciable taste. The control is common tea (CT) with 6 - 10 mm long leaves. Blend tea (BT) was prepared by mixing 5 mm and 120 - 130 mm long tea leaves in a ratio of 3:2. The catechin content of hot water extracts was analyzed by HPLC, and the sensory test was conducted with 99 volunteers. In BT, the total catechin content was significantly higher than that in CT. The sensory test results revealed that BT was less bitter and had more preferable color than CT. More catechins were extracted from BT, but it tasted less bitter. Thus, the recalibration of the tea leaf particle size can result in good balance between catechin content and palatability.

The Relationships between Dyeing Methods and Dyeability in Hair Colouring by Utilising Enzymatic Oxidation of (+)-Catechin

The enzymatic oxidation of (+)-catechin (Cat) with copper-containing oxidase, tyrosinase, was applied to hair colouring in the study. The Cat is oxidised to be o-benzoquinone form, the catechinone, which works as the hair dyestuff. Four kinds of hair colouring techniques using Cat were examined and each of their dyeability was compared in order to improve it. The first dyeing method is dyeing hair by the redissolved catechinone, which is preliminarily obtained by the oxidation of Cat (Redissolution Dyeing Method). The second one is dyeing hair in the dye solution just after the dye being formed by the enzymatic reaction (Sequential Dyeing Method). The third one is dyeing hair in solution containing Cat and the dyeing process is accompanied by the oxidation of Cat (Simultaneous Oxidation Dyeing Method). The fourth one is two-step dyeing that the hair immersed in Cat solution at the first step and then it is oxidised enzymatically to colour at the second step (Post-Oxidation Dyeing Method). The hair is dyed pale yellow by Redissolution Method, deeper yellowish brown by Sequential and Simultaneous Oxidation Dyeing Method and slightly reddish brown by Post-Oxidation Method with Cat. The order of their dyeability is the Simultaneous Oxidation ≈ Post-Oxidation > Sequential > Redissolution Dyeing Method at 30°C. The dyeability of Redissolution Method increases with an increase in dyeing temperature (T) between 20°C - 60°C. In Simultaneous Oxidation Method, the T increment also provides higher dyeability, and the colour of dyed hair becomes duller over 50°C. The Post-Oxidation Method shows higher dyeability at the lower oxidation temperature (20 °C - 40°C).

Adsorption Isotherms of Quercetin and Catechin Compounds on Quercetin-MIP

A molecular imprinted polymer（MIP） was prepared with quereetin as the template and methaerylie acid（MAA） as the functional monomer. Aeetonitrile and methanol were used as the porogen with ethylene glycol dimethaerylate （EGDMA） as the erosslinker and 2,2＇-azobis （ isobutyronitrile ） （ AIBN ） as the initiator. The experimental parameters of the equilibrium isotherms were estimated via linear and nonlinear regression analyses. The linear equadon as the functions of the adsorption concentration of the single compound in its solution and the competitive adsorption of the single compound in its mixed compounds solution was then expressed, and the adsorption equilibrium data were correlated to Langmuir and Freundlich isotherm models. The mixture compounds show competitive adsorption on the specific binding sites of quereetin-MIP. Furthermore, the competitive Langmnir isotherms were applied to the mixture compounds. The adsorption concentrations of quercetin, （＋）eatechin（＋C）, and （-）epieateehin（EC） on the quercetin molecular imprinted polymer were compared. The quercetin-imprinted polymer shows extraordinarily higher adsorption ability for quercetin than for the two eateehin compounds that were also assessed.

Relationship between Dyeing Condition and Dyeability in Hair Colouring by Using Catechinone Prepared Enzymatically or Chemically from (+)-Catechin

Hair colouring was carried out by using catechinone prepared from (+)-catechin by enzymatic or chemical oxidation reaction. The difference of dyeability between the catechinone produced by enzymatic reaction (EC) and that produced by chemical reaction (CC) was studied changing the dyeing condition such as dye concentration, dyeing temperature, pH or the sort and concentration of salts. The colour of the hair dyed by EC or CC at 30°C is yellowish or reddish brown, respectively. The colour of the hair dyed by EC and CC is deeper at a higher dye concentration and at a higher temperature. Hair is dyed deepest by EC or CC at the solution pH = 6.04 or 5.45, respectively. The dyeability is increased by adding NaCl (≤4 M) or CaCl2 (≤1 M), while it is decreased by adding AlCl3. The colour fastness of the dyed hair to washing or ultraviolet light is high enough for practical use. Furthermore, it was found that colourants are obtained from tea extracts which contain catechin derivatives. Hair is dyed reddish brown by the colourants.

Catechin and Epicatechin. What’s the More Reactive?

Catechin and epicatechin are two isomeric flavonoids. Despite the vital properties highlighted by numerous scientific studies, very little data is available on the intrinsic reactivity of these compounds. To provide more details on the stability and reactivity of catechin and epicatechin, this study is performed by means of theoretical calculation methods. For this purpose, geometry optimizations and frequency calculations at the B3LYP/6-31 + G (d, p) level of theory has been carried out and Natural Bond Orbital (NBO) analysis and VEDA (Vibrational Energy Distribution Analysis). The geometric and energy parameters and NBO analysis show that catechin appears more stable than epicatechin. The hydroxyl group position on the ring C of the catechol structure represents a factor that influences this relative stability. The global and local reactivity parameters reveal that epicatechin becomes more reactive than catechin. They indicate that their hydroxyl groups correspond to their most receptive sites. Fukui indices, VEDA and acidity study establish that O28–H29 remains the most reactive.

Hair Dyeing by Using Catechinone Obtained from (+)-Catechin

A novel colourant for hair dyeing was prepared by an enzymatic reaction with (+)-catechin and its characteristics as a hair dyestuff were studied. The study is aimed at inventing the hair dyestuff that is human- and eco-friendly. One potentially powerful dyestuff was obtained from (+)-catechin treated with tyrosinase after screening experiments using biobased materials. The obtained reddish orange colourant, 4-(3,4-dihydro-3α,5,7-trihydroxy-2H-1-benzopyran-2α-yl) 1,2-benzoquinone named “catechinone”, shows enough dyeability for decolourised white hair. Catechinone does not cause erythema or oedema on skin of rabbits. The colour is controlled by the addition of other biobased materials and a variety of colours of dyed hair are acquired. The fastness to light or washing for hair dyed by catechinone is high enough for practical use.

Effect of Reaction Conditions on Production of Catechinone Hair Dyestuff in Water/Alcohol Mixed Solution

Catechinone hair dyestuff was produced chemically from (+)-catechin by the oxidation with O2 in basic water/alcohol mixed solution. The effects of reaction conditions such as basicity, sorts of added base, temperature, alcohol molar fraction of solvent and sorts of added alcohols on the catechinone formation were studied in order to increase the efficiency of the dyestuff production. The amount of obtained catechinone increases with increasing basicity of the reaction solution. The dyestuff is obtained by adding monoethanol amine, diethanol amine, triethanol amine, l-arginine, Na2CO3, K2CO3, Na3PO4 or NaOH into the solution as a base and the most preferable base is monoethanol amine. The optimum temperature for the production in water/ethanol solution is 30°C. It was found that water-soluble alcohols such as methanol, ethanol, 2-propanol, 1-propanol and tert-butyl alcohol are available for preparing the dyestuff. The optimum alcohol molar fraction of the mixed solvent used for the dye formation is 0.45 for methanol, 0.25 for ethanol and 0.20 for 2-propanol, 0.15 for 1-propanol and 0.10 for tert-butyl alcohol. The amount of the obtained dyestuff reaches a maximum at 1) 0.35 and 0.59, 2) 0.35 or 3) 0.35 mol·kg¨1 of the concentration of (+)-catechin for the 1) water/methanol, 2) water/ethanol or 3) water/1-propanol system, respectively.

Qualitative analysis of catechins from green tea GMB-4 clone using HPLC and LC-MS/MS

Objective:To identify the bioactive compounds in catechins isolation and its components from green tea GMB-4 clone.Methods:Green tea GMB-4 clones were extracted with distilled water at 90C.Samples were eluted into the column with 10%ethanol.Subsequently,the column was eluted with95%ethanol and evaporated separately.Green tea extract was identified by thin layer chromatography.Catechins were separated by the stationary phase in column chromatography using polyamide with 10%ethanol eluent and 95%ethanol.The results of isolations were analyzed by high performance liquid chromatographic(HPLC)and LCMS/MS.Analysis of catechins by HPLC was done by external standard.Results:Fraction from 10%ethanol showed that four major peaks at retention time of1.663,2.367,2.950 and 4.890,indicated the presence of four catechins components including catechin,epicatechins,gallocatechin and epigallocatechin.Whereas,fraction from 95%ethanol showed two main peaks at retention time of 5.167 and 9.82,which indicated the presence of epigallocatechin gallate(EGCG)and epicatechin gallate(ECG).EGCG(m/z 459),epigallocatechin(m/z 307),ECG(m/z 443),and epicatechin(m/z 291)were isolated and separated successfully using HPLC and LC-MS/MS.Conclusions:The HPLC and LC-MS/MS methods were successfully tuned for the qualitative analysis of green tea extract with EGCG and ECG.Four major catechins were separated and identified by LC-MS/MS,such as EGCG,epigallocatechin,ECG and epicatechin.The result of HPLC analysis showed that EGCG and ECG were main components from catechins isolation of green tea GMB-4 clone.

Determination of Residual Catechins, Polyphenolic Contents and Antioxidant Activities of Developed Theaflavin-3,3’-Digallate Rich Black Teas

This study was carried out to characterize total residual catechins and their fractions, polyphenolic contents and antioxidant activities of black teas enriched with high levels of theaflavin-3,3’-digallate. The made teas were processed from eleven selected cultivars. A comparative study was carried out between the processed teas and those from commercially grown Kenyan cultivars in relation to the above chemical parameters. A correlation matrix analysis was also conducted to find out whether a relationship existed between the antioxidant activities and the said chemical parameters. The total residual catechins were found to range between 3.10% and 8.08%. The total polyphenol levels varied between 19.00% and 28.90%, while the antioxidant activities of the teas ranged from 82.70% to 91.70%. There was a significant p < 0.001 correlation between the antioxidant activity and total polyphenols (r = 0.8948). There was also a high correlation p < 0.001 between the antioxidant activity and total catechins (r = 0.8878). Out of the four catechin fractions, the antioxidant activity correlated most with EGCG (r = 0.8774). The total polyphenolic contents and antioxidant activities for most of the cultivars were comparable to those of the green tea reference standard. From the figures obtained, it can be concluded that the most of the newly developed black teas of the selected cultivars have higher quality and enhanced antioxidant activities and that they can be recommended for commercial production.

Green tea catechins inhibit microglial activation which prevents the development of neurological disorders

The over-activated microglial cells induce neuroinflammation which has the main role in neurological disorders.The over-activated microglia can disturb neuronal function by releasing inflammatory mediators leading to neuronal dysfunctions and death.Thus,inhibition of over-activated microglia may be an effective therapeutic approach for modulating neuroinflammation.Experimental studies have indicated anti-neuroinflammatory effects of flavonoids such as green tea catechins.The current research was aimed to review the effect of green tea catechins in inhibiting microglial cells,inflammatory cascades,and subsequent neurological diseases.

Simultaneous Determination of Catechins and Caffeine in Green Tea-Based Beverages and Foods for Specified Health Uses

Catechins in green tea have various useful features including antioxidant activity and preventive effects on metabolic syndrome. Various beverages that are enriched with tea catechins are marketed as Foods for Specified Health Uses (FOSHU) in Japan. However, recent reports have indicated that excessive consumption of green tea extracts as a dietary supplement are associated with adverse health effects such as liver disorders. Various catechins and caffeine are constituents of FOSHU tea-based beverages. The amount of catechins in FOSHU products is displayed on labels as total catechin content, but the content of individual catechins are not provided. Although health hazards of FOSHU products have rarely been reported, precise information about the content and types of catechins in FOSHU products is needed to ensure safety. We used high-performance liquid chromatography with a photodiode array (HPLC/PDA) to simultaneously identify and quantify catechins and caffeine in green tea-based popular beverages and FOSHU beverages. This technique allowed simultaneous quantitation of five types of catechins and caffeine in green tea without complicated sample preparation. Epigallocatechin gallate (EGCG) and epigallocatechin EGC were the main catechins in various FOSHU beverages and the concentrations of almost all catechins were higher in FOSHU, than in popular green tea-based beverages. The concentrations of EGCG in green tea-based popular beverages and in FOSHU beverages were 5.4 - 7.3 and 10.2 - 41.9 mg/100mL, respectively, with the highest concentration being in a product named Healthya (approximately 147 mg/bottle). The simultaneous determination of compounds such as catechins and caffeine in FOSHU beverages can help to estimate beneficial and adverse effects to prevent deleterious effects on health and the excessive consumption of FOSHU beverages containing high concentrations of tea catechins should be avoided.

Identification of miRNAs and target genes regulating catechin biosynthesis in tea (Camellia sinensis)

Micro RNAs（miRNAs） are endogenous non-protein-coding small RNAs that play crucial and versatile regulatory roles in plants. Using a computational identification method, we identified 55 conserved miRNAs in tea（Camellia sinensis） by aligning miRNA sequences of different plant species with the transcriptome library of tea strain 1005. We then used quantitative real-time PCR（qRT-PCR） to analyze the expression of 31 identified miRNAs in tea leaves of different ages, thereby verifying the existence of these miRNAs and confirming the reliability of the computational identification method. We predicted which miRNAs were involved in catechin synthesis using ps RNAtarget Software based on conserved miRNAs and catechin synthesis pathway-related genes. Then, we used RNA ligase-mediated rapid amplification of c DNA ends（RLM-RACE） to obtain seven miRNAs cleaving eight catechin synthesis pathway-related genes including chalcone synthase（CHS）, chalcone isomerase（CHI）, dihydroflavonol 4-reductase（DFR）, anthocyanidin reductase（ANR）, leucoanthocyanidin reductase（LAR）, and flavanone 3-hydroxylase（F3H）. An expression analysis of miRNAs and target genes revealed that miR529d and miR156 g-3 p were negatively correlated with their targets CHI and F3H, respectively. The expression of other miRNAs was not significantly related to their target genes in the catechin synthesis pathway. The RLM-RACE results suggest that catechin synthesis is regulated by miRNAs that can cleave genes involved in catechin synthesis.

Feasibility Study of the Synthesis of Isocyanate-Free Polyurethanes from Catechin

With the current trend of increasing efforts to develop non-isocyanate-based polyurethanes(NIPUs),this study aimed to check the feasibility of the development of a method using cyclic carbonate modified catechin and amine to synthesis non-isocyanate urethane with the objective to further extend these results to polyurethane synthesis.The methods used in this study consist of four steps:glycidilation of catechin,hydrolysis of epoxide,cyclic carbonate synthesis,and carbamate synthesis through condensation of butylamine.The resulting products were analyzed using FTIR(Fourier transform infrared)spectroscopy and NMR(nuclear magnetic resonance)spectroscopy.The results showed that carbamate could be successfully obtained through this four-steps synthesis,opening the possibility to further developments for the synthesis of polyurethanes starting from catechin and condensed tannins.

The effects of circadian rhythm on catechin accumulation in tea leaves

As the major bitter-and astringent-tasting components in tea leaves,catechins play an essential role in determining flavor characteristics and health benefits of tea products.This study analyzed the circadian rhythm effects on the accumulation pattern of catechins in tender leaves of three tea cultivars,'Huangkui'(HK),'Longjing43'(LJ43)and'Fuding Dabaicha'(FD).There were two major factors involved in the catechin regulation in tea plants:genetic background of the cultivar-specific regulation,and temporal effects of the circadian rhythm.Etiolated leaves of'HK'contained lower levels of catechins than'LJ43'and'FD'.The composition of EGCG in total catechins was significantly higher in'LJ43'leaves(65%)when compared with that in'HK'and'FD'(45%).The accumulation of individual catechins increased during the daytime but decreased overnight,especially over the time period of 22:00−02:00.The correlation analysis between catechins and environmental factors indicated catechin accumulation in tea leaves potentially resulted from a combined regulation of light and temperature.These findings provide new insights into our understanding of circadian rhythm regulation on flavor-important secondary metabolites in tea leaves.

Determination and pharmacokinetic study of catechin in rat plasma by HPLC

A high performance liquid chromatographic method was developed and validated for the quantitative determination of catechin in rat plasma and its pharmacokinetic study after intragastric administration of Catechu and Xiongdanjiangre Wan into SD rats. Plasma samples were prepared by protein precipitation using methanol-5% aqueous zinc sulfate （70：30, v/v） as precipitant. Chromatographic separation was achieved on Hypersil Cl8 column （250 mm~ 4.6 mm, 10 pm） with acetonitrile-water-triethylamine （6：94：0.3, v/v/v, pH 4.0＋0.1, adjusted with phos- phoric acid） as mobile phase, followed by a UV detection at 207 nm. Good linearity was obtained over the range of 0.143-7.15 mg/L of catechin, with correlation coefficient of 0.9992. The method was simple, sensitive, accurate and reproducible and＇ has been successfully applied to the pharmacokinetic study of catechin in rat plasma.

Investigation of the Interaction Between Sodium (meta) Arsenite and Catechin via ESI Tandem Mass Spectrometry

Catechin,one of the main components of green tea,is considered to have the remedy effect of arsenic poison,although the chemical mechanism is not well known.In this study,sodium（meta）selenite,which is used as herbicide and insecticide as well as rodenticide,was simply mixed with catechin in the CH3OH/H2O（volume ratio 50∶50）solution to investigate the interaction between toxic inorganic arsenic compound and catechin via ESI tandem mass spectrometry.The interaction products of mono-methylated arsenic with catechin in the presence of methanol were identified in the negative mode.Collission induced dissociation（CID）mass spectrometric measurements indicate that monomethylated arsenic was ＂alkylated＂ strongly by conjugation at the sites of C2＇ and C5＇ in the phenyl ring B of the catechin.The interaction mechanism between sodium（meta）arsenite and catechin was proposed.The results provide useful information to understand the chemical pathway of the detoxification of the arsenic toxicity by catechin.

Catechins Green Tea GMB4 Clone Increases mRNA of ABCA1 through LXR Signaling in Cultured Macrophage Exposed OX-LDL

Inhibition of atherogenesis through inhibition of lipid metabolism has not been explored while other inhibitions through inflammation, endothelial dysfunction and free radicals have done. Inhibition of atherogenesis via inhibition of lipid metabolism can be done through the mechanism of Reverse Cholesterol Transport (RCT). Signaling pathways that play a role in this mechanism is LXR signaling. LXR activation by an LXR agonist led increasing cholesterol efflux. Catechins based on bioinformatics study showed as a potent candidate LXR agonists that can be used as an inhibitor of atherogenesis. This study aims to prove that the administration Catechins green tea Clone GMB4 can prevent atherosclerosis through increasing mechanism cholesterol efflux from macrophage by taking effect of ABCA1, ABCG1, SRB1 gene expression in cultured macrophages were exposed ox-LDL. Long-term goals of the outcome of the research are the use of Catechins Green Tea Clones GMB4 as an inhibitor of atherogenesis so that it can be used as a complementary therapy for the treatment of atherosclerosis and cardiovascular diseases. The research is divided into 5 groups, namely the culture of macrophages without exposed ox-LDL, culture exposed ox-LDL and groups of Catechins dose I, II, III. In vitro study showed that administration of Catechins increases mRNA of ABCA1, whereas mRNA ABCG1 and SRB1 decreased at all three doses given. The result of protein profilling was identified a protein with a molecular weight of 70 kDa by SDS-PGE with silver staining.

Tyrosinase Biosensor Used for the Determination of Catechin Derivatives in Tea: Correlation with HPLC/DAD Method

Tea, one of the most popular consumed worldwide beverages, is known to be rich in polyphenols, more particularly in catechins. An amperometric biosensor based on tyrosinase was developed in order to monitor the phenolic content in black and green teas. The enzyme was immobilised by coreticulation with glutaraldehyde on carbon screen-printed electrodes (CSPE). Initially, the performances of the biosensor were evaluated referring to catechol as a model substrate. This analytical tool exhibits a high sensitivity (217 nA/μM), low limit of detection (LOD) = 0.03 μM, good intra-electrode and inter-electrode reproducibilities with RSD lower than 3% (n = 5 injections) and RSD = 8.14% (n = 12 sensors) respectively. The storage stability was also studied;the biosensor retained successively 85% and 70% of its initial response after 34 and 53 days. Subsequently, several catechin derivatives frequently found in teas were tested and classified relatively to their sensitivities. For tea samples, the results obtained with the biosensors were compared to high performance liquid chromatography (HPLC) analysis. A good correlation between the two methods was obtained. The calculated recovery was between 90% and 96%, proving that the proposed tyrosinase biosensor can be an alternative analytical tool for global determination of catechin derivatives in tea.

Variation in Catechin Composition of Popularly Cultivated Tea Clones in East Africa (Kenya)

Tea polyphenols and catechins have gained prominence in determination of tea quality. Tea leaves contain large amounts of catechins and their derivatives and these have shown positive effects on human health. An experiment was carried out to determine the level of catechins and polyphenols in 20 new clones found in two distinct tea growing areas. The trial comprising twenty clones was established in two distinct sites in Kenya using randomized complete block design with three replicates and consisted of 10 popular cultivars widely cultivated in the Lake Victoria Basin and additional 10 newly improved clones. Tea leaf samples were collected across two seasons;dry and wet seasons. Tea quality parameters entailing catechins, caffeine and total polyphenols was generated for the 20 clones across the two seasons and sites. The ISO 14502-1 and ISO 14502-1:2005 procedures were used for polyphenol and catechin analyses, respectively. The ANOVA results generated indicated that the level of catechins and polyphenols in tea were significantly different (p 0.05) and varietal dependent. Generally, the assam varieties had higher levels of catechins and polyphenols than the chinary and cambod varieties, indicating why they are popularly cultivated in the East African region and whose tea quality is highly regarded. Furthermore, the results from principle component analysis (PCA) grouped the clones into three major clusters with one comprising of high quality assam varieties, a mixture of moderate quality assam, cambod and chinary varieties and low catechin content assam anthocyanin-rich variety. It is concluded that the level of catechins in tea plants are varietal dependent, although environmental stress has effects on the synthesis of flavanoids. The results demonstrated that the differences in the accumulation of catechins among the tea clones could be important for the discrimination of clonal diversity.