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.

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.

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.

Lipopolysaccharide-Deficient Mutants of <i>Salmonella enterica</i>Have Increased Sensitivity to Catechins

Antimicrobial activity is one of the well-known biological characteristics of catechins, the main extract of green tea leaves. It is thought that catechins intercalate into the bacterial cell membrane and damage the lipid bilayer. However, the association between catechins and lipopolysaccharides, which consist of an O side chain, core oligosaccharide, and lipid A, has not been previously investigated. In this study, we evaluated the catechin sensitivity of Salmonella enterica mutants that lack the O side chain and have core oligosaccharides of different lengths. These rough mutants were more sensitive to catechins than a bacterial strain with intact lipopolysaccharide. We conclude that the O side chain and core oligosaccharide play an important role in protecting Gram-negative bacteria against the antimicrobial activity of catechins.

AB016:Metabolomic studies of green tea catechins and its applications in ocular research

Tea is the second most popular beverage worldwide after water.Green tea has the highest nutraceutical values with well-established general health benefits and wide safety margins.Natural polyphenols found in green tea,including(+)-catechin(C),(-)-epicatechin(EC),(+)-gallocatechin(GC),(-)-epigallocatechin(EGC),(-)-epicatechin-3-gallate(ECG),(-)-gallocatechin-3-gallate(GCG)and(-)-epigallocatehin-3-gallate(EGCG).They have many potent biological properties and therapeutic effects in human health and diseases.These small molecules have high bioavailability and specific therapeutic potential in eye tissues.Recently some researchers studied the metabolomic responses to the green tea.In this talk,summary of these studies will be reviewed and its potential applications in the ocular research will be discussed.

Effects of thermally modified green tea catechins on the oxidative and hydrolytic stability of butter

Green tea catechins are classified as (-)-epi-forms (2R, 3R) or (-)-forms (2S, 3R) with respect to stereoisomerism. The (-)-forms (2S, 3R) in catechin preparations obtained from green tea amounts to approximately 10% of total catechins, whereas the other 90% are (-)-epiforms (2R, 3R). High temperature induces the conversion of (-)-epiforms (2R, 3R) to (-)-forms (2S, 3R). This study investigated the effect of catechin prepa-rations containing 10, 20 and 30% (-)-forms (2S, 3R) on the oxidative and hydrolytic stability of butter. For comparison, butter with δ-tocopherol and BHT and butter without stabilizer were analysed. Butter stability was examined under conditions of refrigeration (8 oC) and freezing (-22 oC) and at temperature of 50 oC and 100 oC. Catechin preparations were more efficient butter stabilizers than BHT and δ-tocopherol. Thermal modification of catechins that led to the genera-tion of 20% of (-) forms (2S, 3R) improved their antioxidative efficacy, but longer treatment lead- ing to the formation of 30% of (-) forms (2S, 3R) decreased their antioxidative activity. The hy-drolytic stability of butter, however, increased as the amount of (-) forms (2S, 3R) increased.

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.

Metabolic profile analysis based on GC-TOF/MS and HPLC reveals the negative correlation between catechins and fatty acids in the cottonseed of Gossypium hirsutum

Background: The diversified and high value-added utilization of cotton by products can promote the sustainable development of modern agriculture. Di erences in potential nutrients among varieties can be explained by variations in the composition and abundance of fatty acids, polyphenols, carbohydrates, amino acids, and organic acids. Therefore, the analysis of metabolite species and relationships in cottonseed is meaningful for the development of cotton byproducts.Results: In this study, the metabolomes of three representative cotton cultivars of di erent species were compared using untargeted GC-TOF/MS analysis. A total of 263 metabolites were identified from 705 peaks, and their levels were compared across cultivars. Principal component analysis and OPLS-DA clearly distinguish these samples based on metabolites. There were significant di erences in the contents of amino acids, carbohydrates, organic acids, flavonoids, and lipids in G. hirsutum TM-1 compared with G. arboreum Shixiya1 and G. barbadense Hai7124. Notably, the bioactive nutrient compound catechin obtained from the di erential metabolites significantly accumulated in TM-1. Furthermore, a comprehensive analysis using catechin and oil-related traits was conducted in core collections of Gossypium hirsutum. The results revealed the reliability of the GC-TOF/MS analysis, as well as that catechin content has a negative association with myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, arachidic acid, and total fatty acids.Conclusion: These findings suggest that untargeted GC-TOF/MS analysis could provide a new method for investigating the underlying plant biochemistry of nutrient variation in cottonseed, and that catechin content has a negative association with oil-related traits in cottonseed. This study may pave the way to exploit the value of cotton byproducts.

Effects of catechins on litter size,reproductive performance and antioxidative status in gestating sows

This study was conducted to investigate the effects of catechins on reproductive performance, antioxidative capacity and immune function of gestating sows. A total of 60 cross-bred（Landrace × Large White） multiparious sows were blocked by body weight, parity and backfact and randomly allocated to 1 of 5 treatments: 0.100,200,300, or 400 mg/kg catechins. Dietary treatments were imposed from mating to d 40 of gestation of sows. At farrowing, litter total born, born alive, dead, and normal-（healthy piglets,>0.85 kg） and low-birth weight piglets（<0.85 kg） were recorded. Within 3.00 ± 0.50 days after farrowing litter size was standardized to 8,00 ± 1.50 piglets within treatment. The piglets were weighed at birth（d 1） and weaning（d 28）. Sows serum samples were obtained from blood samples collected on d 40 of gestation for analyses of glutathione peroxidase（GSH-Px）, superoxide dismutase（SOD）, catalase（CAT）,malondialdehyde（MDA）, hydrogen peroxide（H2 O2）, nitric oxide synthetase（NOS） and nitrogen monoxide（NO）. Our results showed that supplementation of catechins at levels of 200 or 300 mg/kg led to improvements in litter born alive（P < 0.01） and piglet born healthy（P < 0.01） and a decrease in stillborn（P < 0.05） at farrowing when compared with the control. In comparison with the control, catechins at any supplemental levels all enhanced the serum SOD（P < 0.05） and CAT（P < 0.01） activities of sows at farrowing but no obvious differences in the serum GSH-Px and NOS activities were observed in this trial（P > 0.05）. Sows received 200 mg catechin per kg diets showed a reduction（P < 0.05） of the serum MDA level at farrowing compared with all other treatments. Sows received all the levels of catechin showed a reduction（P < 0.05） of serum H2 O2 level compared with sows received the control diet on both d 40 of gestation and farrowing. Our results demonstrated that the catechins may be a potential antioxidant to increase the reproductive performance and antioxidative capacity of sows when it was added into diets during the early gestation.

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.

我国苦茶资源主要生化成分的鉴定评价(英文)

Bitter tea is a special kind of tea germplasm in China.The major biochemical components of 24 bitter teas and other 8 Camellia sinensis var.sinensis and 8 C.sinensis var.assamica tea germplasms,which were stored in the China National Germplasm Hangzhou Tea Repository(CNGHTR),were analyzed and evaluated.The results showed that no significant differences of major biochemical components affecting the tea quality were found between bitter tea and common tea.According to the processing suitability index,bitter tea was suitable for the manufacturing of black tea;while according to evolutionary indices such as the composition and content of catechin,bitter tea was similar to C.sinensis var.assamica belonging to the relatively primitive type in evolution.The results of cluster analysis indicated that bitter tea was clustered with C.sinensis var.assamica,so it could be considered to belong to C.sinensis var.assamica.

Black tea in chemo-prevention of cancer and other human diseases

Tea is the most popular functional beverage in the world and has been gaining more and more attention for its health beneficial properties.Among common teas,black tea is consumed more than green tea and oolong tea worldwide.Numerous studies have shown the biological activities of black tea and its polyphenols that include anti-oxidant,anti-tumor,anti-inflammation and metabolic regulation.Tea polyphenols such as theaflavins and catechins are considered to be multifunctional compounds that could be effective in the prevention or treatment of various cancers,cardiovascular disease,chronic inflammation,obesity,metabolic syndrome,and neurodegenerative diseases.In this review,we summarized the up-to-date research and underlying molecular mechanisms of black tea and its polyphenols.©2013 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

Chemoprevention of obesity-related liver carcinogenesis by using pharmaceutical and nutraceutical agents

Obesity and its related metabolic disorders are serious health problems worldwide,and lead to various healthrelated complications,including cancer.Among human cancers,hepatocellular carcinoma(HCC)is one of the most common malignancies affected by obesity.Therefore,obesity and its related disorders might be a key target for the prevention of HCC.Recently,new research indicates that the molecular abnormalities associated with obesity,including insulin resistance/hyperinsulinemia,chronic inflammation,adipokine imbalance,and oxidative stress,are possible molecular mechanisms underlying the pathogenesis of obesityrelated hepatocarcinogenesis.Green tea catechins and branched-chain amino acids,both of which are classified as nutraceutical agents,have been reported to prevent obesity-related HCC development by improving metabolic abnormalities.The administration of acyclic retinoid,a pharmaceutical agent,reduced the incidence of HCC in obese and diabetic mice,and was also associated with improvements in insulin resistance and chronic inflammation.In this article,we review the detailed molecular mechanisms that link obesity to the development of HCC in obese individuals.We also summarize recent evidence from experimental and clinical studies using either nutraceutical or pharmaceutical agents,and suggest that nutraceutical and pharmaceutical approaches targeting metabolic abnormalities might be a promising strategy to prevent the development of obesity-related HCC.

Effects of Grape Balanced Nutrition Fertilizer on Yield and Quality of Wine Grapes

In this study,the wine grapes balanced nutrient fertilizer(BNF)was designed according to the wine grape nutritional requirements in different growth stages,and objected to reduce fertilizer application rate of wine grape cultivation,improve fertilizer utilization rate,achieve stable yield and improve the quality of wine grapes.The experiment was carried out at the Great Wall Sanggan Winery,and the Aristocratic Winery.The experiment was designed with two treatments:Namely BNF treatment,and the traditional fertilization(CK).We investigated the effects of BNF on the quality of wine grapes by examining the plant traits of wine grapes in different experimental areas during the growing season,the fruit traits at maturity,and determined the contents of VC,organic acids,amino acids,flavonoids,soluble total sugars,soluble solids,tannins,total phenols and catechins.The results show that:①The application of grape BNF greatly reduced the application amount of nitrogen,phosphorus and potassium,while the vine had no fertilizer deficiency phenomenon;②It increased the single fruit weight,the ear weight and yield to varying degrees,and the yield increase range was between 12% and 41%;③The wine grapes with BNF had the following characteristics:tight infructescence,even color,small fruit less,no fruit dropped,strong fruit colloid feeling,better aroma and taste;④It greatly improved the quality of wine grapes,and increased the content of soluble solids,soluble total sugar,organic acids,VC,total phenols,flavonoids,amino acids and tannins in fruits;⑤It greatly increased the total catechin content of"Riesling"and"Syrah",and had no significant effects on the catechin content of"Merlot"and"Cabernet Sauvignon".In summary,the application of grape BNF has certain practical significance for guiding the production of local wine grapes,ensuring the yield while improving the quality,increasing the income and reducing the environmental pollution caused by excessive fertilization.

LC-ESI-IT-MS/MS and MALDI-TOF Approach:Identification of Natural Polymers from Rhizophora mangle Barks and Determination of Their Analgesic and Anti-inflammatory Properties

We recognize the chemical composition of the acetonic extract of Rhizophora mangle barks(AERM)using mass spectrometry analysis[liquid chromatography(LC)–ESI–IT-MS/MS and matrix-assisted laser desorption/ionization-time of flight-MS(MALDI-TOF)].Analgesic activity was evaluated by formalin and tail-flick experimental assays.Anti-inflammatory activity was performed by paw edema test induced by carrageenan and 48/80 compounds.The first series of experiments involved[LC]–FIA–IT-MS/MS with 11 separated catechins derivatives until degree of polymerization 3(DP3).The spectra obtained by MALDI-TOF analysis of the AERM presented two homologous series:one based on polymers of m/z 288 Da increments(up to DP12)and another series based on polymers of m/z[288?162]Da increments(up to DP11).In addition to these series of flavan-3-ol,each DP had a subset of masses with a variation of-16 Da(homologous series of afzelechins-m/z 873–3465 Da)and +16 Da(homologous series of gallocatechins-m/z 905–3497 Da).A similar pattern with homologous series of gallocatechins and afzelechins could also be observed for a fifth and a sixth monohexoside series:glucogallocatechins(m/z 779–3371)and glucoafzelechins(m/z 747–3339).The intraperitoneal administration of different doses of AERM(50,150 and 300 lg mL^(-1))have a morphine-like effect and intense anti-inflammatory activity.

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.

Tea Identification through Surface-Assisted Laser Desorption/Ionization Mass Spectrometry

We have applied surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) usingtitanium dioxide nanoparticles(TiO2NPs)as the matrix and captopril (CAP) as internal standard for the determination of the concentrations of theanine and four catechins—catechin, (_)-epigallocatechin (EGC), (_)-epicatechin gallate (ECG), and (_)-epigallocatechin gallate (EGCG).Under the optimal conditions (240 nM TiO2 NPs and 10 μM CAP), this SALDI-MS approach provides linearity of 0.3– 80 (r= 0.990), 1.2–100 (r= 0.987), 4–120 (r= 0.995), 6–120 (r= 0.983), and 2–120 μM (r= 0.991) for theanine, catechin, EGC, ECG, and EGCG, respectively. The limits of detection (LODs;S/N = 3)for theanine, catechin, EGC, ECG, and EGCG provided by this SALDI-MS approach are 0.1, 0.35, 1.0, 1.45, and 0.5 μM, respectively. This approach provides spot-to-spot and batch-to-batch variations of less than 10% and 13%, respectively, for the analysis of tea samples.With advantages of simplicity, accuracy, precision, and great reproducibility, we have applied the SALDI-MS approach for the analysis of tea samples, with identified peaks for theanine, catechin, EGC, ECG, and EGCG. Tea samples from Taiwan and four other areas have various SALDI-MS profiles, showing their potential for differentiation of tea samples from different sources. Our result also shows that tea samples harvested in different seasons and counties in Taiwan provide significantly different MS profiles. The amounts of theanine and EGC in the Oolong tea from Lishan are much higher than those in the other tea samples.

Quantitation of the Total Catechin Content in Oils Extracted from Seeds of Selected Tea (<i>Camellia sinensis</i>(L) O. Kuntze, Theaceae) Clones by RP-HPLC

Catechins (flavan-3-ols) are polyphenolic plant secondary metabolites that have been strongly associated with a wide variety of beneficial health effects in vitro, in vivo and clinically. This study reports findings on the content of catechins in tea seed oil (TSO) extracted by Soxhlet extraction from seeds of different clones of Kenyan tea. Extraction of catechins from the crude oils was achieved by sequential liquid-liquid extraction (LLE) using methanol and quantified by reverse phase High Performance Liquid Chromatography (RP-HPLC). Results obtained revealed that all the crude test oils contained catechins, with oils extracted from clones TRFK K-Purple and GW-Ejulu having the highest total catechin content of 9.8 ± 0.25 and 9.0 ± 0.83 (×10-3% flavonoids) respectively. Statistically significant differences (p < 0.05) were evident in the total catechin contents of crude oils extracted from tea seeds with those extracted from corn, sunflower and soybean seeds. Moreover, clonal variations were evident, as the total catechin contents of oils extracted from clones TRFK K-Purple and GW-Ejulu were statistically different (p < 0.05) from those extracted from clones TRFK 301/3, TRFK 301/4, TRFK 301/5, TRFK 306, TRFK 91/1 and TRFCA SFS 150. Thus, the current findings strongly suggest that oils from seeds of Kenyan tea cultivars can be a potential source of potent natural antioxidants.