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Background and Aims Chinese pistachio (Pistacia chinensis), an important horticultural plant species, holds great ornamental value with beautiful leaves and fruits. Seedling propagation of this tree species is restricted by its erratic seed germination; however, the germination mechanism is ambiguous. The aim of this study was to determine the germination mechanism from a novel perspective based on the multi-omics data. Methods The multi-omics technique combined with hormone content measurement was applied to seed germination of Chinese pistachio. Key Results Due to its great accumulation during seed germination, catechin stood out from the identified metabolites in a broadly targeted metabolomic analysis. Exogenous catechin at 10 mg L−1 significantly improved the germination of Chinese pistachio seeds. An interesting result of hormone analysis was that the improving effect of catechin could be attributed to an increase in gibberellic acid 3 (GA3) content rather than a decrease in abscisic acid (ABA) content before germination. Treatments with paclobutrazol (PAC, a GA biosynthesis inhibitor) and PAC + catechin also showed that the promoting effect of catechin on seed germination depends on GA biosynthesis. Transcriptome analysis and qRT‒PCR further revealed that catechin induced the expression of PcGA20ox5 to activate GA biosynthesis. Several transcription factors were induced by catechin and GA treatments, such as TCP, bZIP and C3H, which may play an important regulatory role in GA biosynthesis in a catechin-mediated way. Conclusions Catechin promotes seed germination via GA biosynthesis in Chinese pistachios. This study proposes a novel mechanism by which catechin promotes seed germination via the GA pathway, which provides new insight into a comprehensive understanding of seed dormancy and germination. [ABSTRACT FROM AUTHOR]

Pinus massoniana needles, a traditional herb, were applied to prevent hair loss in China. Studies available mainly focused on pine needle flavonoids with various biological activities. However, there has been no pharmacokinetics study of the flavonoids from Pinus needles extract. A selective and sensitive ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) method was developed to simultaneously quantify taxifolin, quercetin and catechin in rat plasma. To separate the three constituents, an Agilent Extend-C18 column (2.1 mm × 100 mm, 1.8 μm) was used with a mobile phrase of (A) 0.1% formic acid and (B) acetonitrile. The analytes were measured by multiple reaction monitoring in the negative ionization mode. There was good linearity in the established UHPLC-MS/MS method, with a coefficient of determination (r 2) of >0.99. The accuracy, intra-day and inter-day precision and recovery were all satisfactory and these 3 compounds were stable under the tested conditions. The validated method in this study was successfully applied to pharmacokinetic study in healthy rats after oral and transdermal administration of Pinus needles extract. The results could provide further research foundation for pine needle extract as external preparations. [ABSTRACT FROM AUTHOR]

Glutathione transferase Pi (GSTP1) expression is increased in many cancer types and is associated with multidrug resistance and apoptosis inhibition. Inhibitors of GSTP1-1 have the potential to overcome drug resistance and improve chemotherapy efficacy as adjuvant agents. This study investigated the effects of catechin and gossypol on human glutathione transferase Pi (GSTP1-1) activity and their cytotoxic effects on breast cancer cells (MCF-7) individually and in combination with tamoxifen (TAM). Gossypol effectively inhibited the enzyme with an IC50 value of 40 μM, compared to 200 μM for catechin. Gossypol showed stronger inhibition of GSTP1-1 activity (Ki = 63.3 ± 17.5 μM) compared to catechin (Ki = 220 ± 44 μM). Molecular docking analysis revealed their binding conformations to GSTP1-1, with gossypol binding at the subunit interface in an un-competitive manner and catechin showing mixed non-competitive inhibition. Gossypol had severe cytotoxic effects on both MCF-7 cells and normal BJ1 cells, while catechin had a weak cytotoxic effect on MCF-7 cells only. Combination therapy with TAM resulted in cytotoxicity of 27.3% and 35.2% when combined with catechin and gossypol, respectively. Gossypol showed higher toxicity to MCF-7 cells, but its strong effects on normal cells raised concerns about selectivity and potential side effects. [ABSTRACT FROM AUTHOR]

Artocarpus lacucha, a plant in the Moraceae family, has traditionally been used in Southeast Asian medicine to treat various ailments. This study investigated the insecticidal potential against Spodoptera litura of several compounds extracted from A. lacucha using a topical application method. A sequential extraction method was employed with A. lacucha stems to identify the most toxic crude extract by using hexane, dichloromethane, ethyl acetate, and methanol solvents. Subsequently, the most toxic crude extract was analyzed for chemical composition by HPLC, followed by the isolation process. Among these crude extracts, the ethyl acetate crude extract was the most toxic to second-instar S. litura larvae (24-h LD50 value of ∼9.07 µg/larva). Our results showed that the catechin isolated from the ethyl acetate crude extract exhibited the highest toxicity against this insect (24-h LD50 value of ∼8.37 µg/larva). Additionally, catechin significantly decreased the activities of acetylcholinesterase, carboxylesterases, and glutathione S-transferase in the larvae. These findings suggest that catechin isolated from A. lacucha could be a potential insecticidal agent against S. litura. However, the toxicity and persistence of catechin under field conditions need to be further investigated to develop this novel insecticide. [ABSTRACT FROM AUTHOR]

Camellia oil extracted from the seeds of Camellia oleifera Abel. is a popular and high-quality edible oil, but its yield is limited by seed setting, which is mainly caused by self-incompatibility (SI). One of the obvious biological features of SI plants is the inhibition of self-pollen tubes; however, the underlying mechanism of this inhibition in C. oleifera is poorly understood. In this study, we constructed a semi-in vivo pollen tube growth test (SIV-PGT) system that can screen for substances that inhibit self-pollen tubes without interference from the genetic background. Combined with multi-omics analysis, the results revealed the important role of galloylated catechins in self-pollen tube inhibition, and a possible molecular regulatory network mediated by UDP-glycosyltransferase (UGT) and serine carboxypeptidase-like (SCPL) was proposed. In summary, galloylation of catechins and high levels of galloylated catechins are specifically involved in pollen tube inhibition under self-pollination rather than cross-pollination, which provides a new understanding of SI in C. oleifera. These results will contribute to sexual reproduction research on C. oleifera and provide theoretical support for improving Camellia oil yield in production. [ABSTRACT FROM AUTHOR]

Background: Loss and remodelling of the dermal extracellular matrix (ECM) are key features of photodamaged human skin. Green tea catechins (GTCs) have been explored for their anti‐inflammatory and chemopreventive properties, but data on the impact of GTCs on ultraviolet radiation (UVR)‐induced changes to the dermal ECM are lacking. Aim: To investigate the effect of an inflammatory dose of solar‐simulated UVR on human dermal ECM and potential for protection by GTCs in a double‐blind randomized controlled trial. Methods: In total, 50 healthy white (Fitzpatrick skin type I–II) adults aged 18–65 years were randomized to a combination of GTCs 540 mg plus vitamin C 50 mg or to placebo twice daily for 12 weeks. The impact of solar‐simulated UVR at 3 × minimal erythema dose on the dermal collagen and elastic fibre networks was assessed by histology and immunohistochemistry in all participants at baseline. The impact of GTC supplementation on UVR‐induced effects was compared between the groups post‐supplementation. Results: The area of papillary dermis covered by collagen and elastic fibres was significantly lower (P < 0.001) in UVR‐exposed skin than in unexposed skin. Significantly lower levels of fibrillin‐rich microfibrils (P = 0.02), fibulin‐2 (P < 0.001) and fibulin‐5 (P < 0.001) were seen in UVR‐exposed than unexposed skin, while procollagen‐1 deposition was significantly higher in UVR‐exposed skin (P = 0.01). Following GTC supplementation, the UVR‐induced change in fibulin‐5 was abrogated in the active group but not the placebo group, with no difference between the two groups for other components. Conclusions: Acute UVR induced significant changes in the human dermal collagen and elastic fibre networks, whereas oral GTCs conferred specific UVR protection to fibulin‐5. Future studies could explore the impact of GTCs on the effects of repeated suberythemal UVR exposure of human skin. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) fungi are an alternative to chemical insecticides or fertilizers, and there is an urgent need to extend the application of AM fungi to woody plants. This study aims to investigate the growth and resistance against the gypsy moth larvae (Lymantria dispar) in Glomus intraradices -colonized Populus alba × P. berolinensis seedlings, and to unravel the transcriptome and metabolome phenotypes recruited by AM fungus colonization that affect plant growth and insect resistance. Our results showed a positive mycorrhizal growth response, i.e. growth and biomass of mycorrhizal seedlings were enhanced. However, AM fungus inoculation reduced the resistance of poplar to gypsy moth larvae, as evidenced by the decreased carbon/nitrogen ratio in leaves, as well as the increased larval growth and shortened larval developmental duration. Transcriptome analysis revealed that in both auxin and gibberellin signaling transductions, all nodes were responsive to AM symbiosis and most differentially expressed genes belonging to effectors were up-regulated in mycorrhizal seedlings. Furthermore, the two key enzymes (4-coumarate-CoA ligase and trans-cinnamate 4-monooxygenase) involved in the synthesis of p -Coumaroyl-CoA, an initial metabolite in flavonoid biosynthesis and the first rate-limiting enzyme (chalcone synthase) in flavonoid biosynthesis, were down-regulated at the transcriptional level. Consistent with the transcriptome results, metabolome analysis found that the amounts of all differentially accumulated flavonoid compounds (e.g. catechin and quercetin) identified in mycorrhizal seedlings were decreased. Taken together, these findings highlight the diverse outcomes of AM fungi–host plant–insect interaction and reveal the regulatory network of the positive mycorrhizal growth response and mycorrhizal-induced reduction of insect resistance in poplar. [ABSTRACT FROM AUTHOR]

Objective: Wine color is considered an important indicator in judging red wine quality and is also employed to evaluate wine aging. However, wine color can be influenced by many factors. Method: In this paper, it was investigated that the effects of caffeic acid and catechin on wine color and related mechanisms by HPLC and ultraviolet-visible spectroscopy for the wine model solutions containing malvidin-3-O-glucoside. The spectrum changes of the model wine solutions (Mv-glc, Mv-glc + caffeic acid, and Mv-glc + catechin) during 120 days storage were monitored to analyze the influence of co-pigmentation on red wine color. Results: The results indicate that the color properties of red wine could be affected by caffeic acid and catechin to a certain extent. Moreover, caffeic acid had a stronger auxiliary color effect on the malvidin-3-O-glucoside than that of the catechin in the model wine solutions, and the former effect continued to increase with prolongation of storage time. The latter effect (catechin) only had a temporary auxiliary color effect in the beginning, and weakened from red to orange yellow with increased storage time. Furthermore, ultrasound irradiation improved co-pigmentation, resulting in the modification of wine color. Conclusions: All results indicate that the co-pigmentation reaction of wine color could be modified by the addition of caffeic acid and ultrasonic treatment to improve the quality of red wine. [ABSTRACT FROM AUTHOR]

The growth of leaves and biosynthesis of characteristic secondary metabolites are critically important for tea production and quality control. However, little is known about the coordinated regulation of leaf development and catechin biosynthesis in tea plants. Here, we reported that TCP TFs are involved in both catechin biosynthesis and leaf development. An integrated analysis of catechin profiling and CsTCP expression in different tissues of plants under various environmental conditions at different developmental stages indicated significant correlations between the transcript levels of CIN-type TCPs and catechin production. CIN-type CsTCP3 and CsTCP4 and PCF-type CsTCP14 interacted with the MYB-bHLH-WD40 repeat (MBW) complex by forming a CsTCP3-CsTT8 heterodimer and modulating the transactivation activity of the promoters of anthocyanin synthase (CsANS1) and anthocyanidin reductase (CsANR1). Four types of microRNA/target modules, miR319b/CsTCP3-4, miR164b/CsCUC, miR396/CsGRF-GIF, and miR165b/HD-ZIPIII ones, were also identified and characterized for their functions in the regulation of the development of tea plant shoot tips and leaf shape. The results of these modules were reflected by their different expression patterns in developing buds and leaves that had distinctly different morphologies in three different tea plant varieties. Their roles in the regulation of catechin biosynthesis were also further verified by manipulation of microRNA319b (miR319b), which targets the transcripts of CsTCP3 and CsTCP4. Thus, CsTCPs represent at least one of these important groups of TFs that can integrate tea plant leaf development together with secondary metabolite biosynthesis. Our study provides new insight into shoot tip development and catechin production in tea plants and lays a foundation for further mechanistic understanding of the regulation of tea plant leaf development and secondary metabolism. [ABSTRACT FROM AUTHOR]

The global pandemic crisis, coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has claimed the lives of millions of people across the world. Development and testing of anti-SARS-CoV-2 drugs or vaccines have not turned to be realistic within the timeframe needed to combat this pandemic. Here, we report a comprehensive computational approach to identify the multi-targeted drug molecules against the SARS-CoV-2 proteins, whichare crucially involved in the viral–host interaction, replication of the virus inside the host, disease progression and transmission of coronavirus infection. Virtual screening of 75 FDA-approved potential antiviral drugs against the target proteins, spike (S) glycoprotein, human angiotensin-converting enzyme 2 (hACE2), 3-chymotrypsin-like cysteine protease (3CLpro), cathepsin L (CTSL), nucleocapsid protein, RNA-dependent RNA polymerase (RdRp) and non-structural protein 6 (NSP6), resulted in the selection of seven drugs which preferentially bind to the target proteins. Further, the molecular interactions determined by molecular dynamics simulation revealed that among the 75 drug molecules, catechin can effectively bind to 3CLpro, CTSL, RBD of S protein, NSP6 and nucleocapsid protein. It is more conveniently involved in key molecular interactions, showing binding free energy (Δ G bind) in the range of −5.09 kcal/mol (CTSL) to −26.09 kcal/mol (NSP6). At the binding pocket, catechin is majorly stabilized by the hydrophobic interactions, displays Δ E vdW values: −7.59 to −37.39 kcal/mol. Thus, the structural insights of better binding affinity and favorable molecular interaction of catechin toward multiple target proteins signify that catechin can be potentially explored as a multi-targeted agent against COVID-19. [ABSTRACT FROM AUTHOR]

The characteristic secondary metabolites in tea (theanine, caffeine, and catechins) are important factors contributing to unique tea flavors. However, there has been relatively little research on molecular markers related to these metabolites. Thus, we conducted a genome-wide association analysis of the levels of these tea flavor-related metabolites in three seasons. The theanine, caffeine, and catechin levels in Population 1 comprising 191 tea plant germplasms were examined, which revealed that their heritability exceeded 0.5 in the analyzed seasons, with the following rank order (highest to lowest heritabilities): (+)-catechin > (−)-gallocatechin gallate > caffeine = (−)-epicatechin > (−)-epigallocatechin-3-gallate > theanine > (−)-epigallocatechin > (−)-epicatechin-3-gallate > catechin gallate > (+)-gallocatechin. The SNPs detected by amplified-fragment SNP and methylation sequencing divided Population 1 into three groups and seven subgroups. An association analysis yielded 307 SNP markers related to theanine, caffeine, and catechins that were common to all three seasons. Some of the markers were pleiotropic. The functional annotation of 180 key genes at the SNP loci revealed that FLS, UGT, MYB, and WD40 domain-containing proteins, as well as ATP-binding cassette transporters, may be important for catechin synthesis. KEGG and GO analyses indicated that these genes are associated with metabolic pathways and secondary metabolite biosynthesis. Moreover, in Population 2 (98 tea plant germplasm resources), 30 candidate SNPs were verified, including 17 SNPs that were significantly or extremely significantly associated with specific metabolite levels. These results will provide a foundation for future research on important flavor-related metabolites and may help accelerate the breeding of new tea varieties. [ABSTRACT FROM AUTHOR]

Bioactive compounds entrapped in plant materials can be effectively recovered using fungal enzymes. Cinnamomum zeylanicum Sri Wijaya (SW) and Sri Gemunu (SG) accessions and commercially available C. zeylanicum (CC) were subjected to fungal pretreatment and extracted with pressured water (PWE, 0·098 MPa). Thirteen fungal species were isolated and the substrate utilization ability of the species was tested using cellulose, pectin and lignin (indirectly). Total phenolic content (TPC, Folin–Ciocalteu method), proanthocyanidin content (PC, vanillin method) and α‐amylase and α‐glucosidase inhibitory potential of the extracts were evaluated. The anti‐diabetic drug, Acarbose was used as the positive control. Trichoderma harzianum (MH298760) showed the highest cell lysis ability and hence was used for the microbial pretreatment process. Extracts of SW treated with T. harzianum species (Pre‐SW) gave the highest percentage yield (4·08% ± 0·15%), significantly potent inhibition (P < 0·05) of α‐amylase and α‐glucosidase activities (IC50 57 ± 8 and 36 ± 8 μg ml−1 respectively), TPC (2·24 ± 0·02 mg gallic acid equivalent g−1), and PC (48·2 ± 0·4 mg of catechin equivalent g−1) compared to Pre‐SG, Pre‐CC and nontreated samples. Trichoderma harzianum treatment can enhance the hypoglycaemic properties, PC and TPC of Cinnamon extracts and provide new insights into the recovery of phytochemicals. [ABSTRACT FROM AUTHOR]

Drying tea flowers into a high-quality product is important to its commodity value. In the present work, a combination of microwave-assisted drying and air drying (MAD-AD) was applied in the processing of fresh tea flowers and its effects on flavor quality, active nutraceutical compounds, and antioxidant capacities were studied. The results showed that compared to air drying and freeze drying tea flowers, the MAD-AD tea flowers had higher amounts of active compounds such as catechins, flavonol glycosides, and triterpenoid saponins, and possessed high antioxidant activities. Moreover, this drying method improved the tea flowers' color and preserved a more floral fragrance. This combined method could be of interest as an industrial method for drying tea flowers with the benefit of reduced processing time, more reserved active compounds and high quality of products. [ABSTRACT FROM AUTHOR]

Hypoglycemic potential and xanthine-oxidase (XO) activity of polyphenols from faba bean were evaluated in the 3T3-L1 cell line, and an interaction study in silico with XO was performed with considerable bioactive components of acetone extract of faba beans. The protonated and fragmented behavior of acetone seed extract revealed the presence of gallic acid (MS/MS, m/z 169) and catechin (MSn, m/z 288.3). Flow cytometry study explained the effect of hydrogen peroxide (H2O2) on cell line as cell death was increased from 9.72 to 41.66% as compared to the control (without H2O2). The atomic force microscopy (AFM), scanning electron microscopy and reactive oxygen species measurement also confirmed the protective effect of polyphenols in the 3T3-L1 cell lines. Oxidative stress through propidium iodide and 4′,6-diamidino-2-phenylindole staining demonstrated that the apoptotic ratio was 0.35 ± 2.62 (P < 0.05) and 30 ± 2.54% in H2O2-treated cells, respectively, as compared to control. The observations of flow cytometry and confocal microscopy marked the effect of seed extract (0.86 ± 0.031, 3.52 ± 0.52, P < 0.05), on glucose uptake in cells through the better relative fluorescence intensity than that of the control. Moreover, molecular docking and molecular dynamics simulation studies gave an insight into the predicted residues that hold favorable polyphenolic-specific interactions. The probable binding modes of the gallic acid and catechin from this study may extend the knowledge of the XO-polyphenol interactions and offered the way to design the analogs of acetone seed extract with reduced toxicity. [ABSTRACT FROM AUTHOR]

Background: Ultra-performance LC (UPLC)–tandem MS (MS/MS) and high-performance TLC (HPTLC) assay methods were developed for chemical fingerprinting and quantitative analysis of bioactive constituents of a certain “Itrifal formulation,” a traditional kind of Unani medicine. Objective: In the present investigation, HPTLC and UPLC-MS/MS methods were developed and validated for the detection and quantification of major metabolites present in itrifal formulation. Methods: The metabolites present in the formulation were separated using modern chromatographic techniques, and a quantitative analysis was performed. Analytical performance of the proposed HPTLC and UPLC-MS/MS methods was validated as per the defined guidelines with respect to linearity, accuracy, precision, robustness, and specificity. Results: The developed UPLC-MS/MS and HPTLC methods were used for quantification of gallic acid, tannic acid, catechin, and quercetin. All four constituents were quantified by UPLC-MS/MS, while two constituents were quantified by HPTLC in the commercial itrifal formulation. The calibration plot was found to be linear, accurate, precise, robust, and specific for both HPTLC and UPLC-MS/MS. Conclusions: The present methods were successfully applied for analysis of the given markers in itrifal formulations. The same can be used for QC and stability testing of itrifal formulations. [ABSTRACT FROM AUTHOR]

Catechins are the predominant products in tea plants and have essential functions for both plants and humans. Several genes encoding the enzymes regulating catechin biosynthesis have been identified, and the identification of single nucleotide polymorphisms (SNPs) resulting in nonsynonymous mutations within these genes can be used to establish a functional link to catechin content. Therefore, the transcriptomes of two parents and four filial offspring were sequenced using next-generation sequencing technology and aligned to the reference genome to enable SNP mining. Subsequently, 176 tea plant accessions were genotyped based on candidate SNPs using kompetitive allele-specific polymerase chain reaction (KASP). The catechin contents of these samples were characterized by high-performance liquid chromatography (HPLC), and analysis of variance (ANOVA) was subsequently performed to determine the relationship between genotypes and catechin content. As a result of these efforts, a SNP within the chalcone synthase (CHS) gene was shown to be functionally associated with catechin content. Furthermore, the geographical and interspecific distribution of this SNP was investigated. Collectively, these results will contribute to the early evaluation of tea plants and serve as a rapid tool for accelerating targeted efforts in tea breeding. [ABSTRACT FROM AUTHOR]

Aims: To study the individual and combined contribution of catechin, protocatechuic and vanillic acids to inhibit the adhesion of uropathogenic Escherichia coli (UPEC) on the surface of silicone catheters. Methods and Results: The adhesion of UPEC to silicone catheters during the exposure to nonlethal concentrations of phenolic compounds was measured, as well as changes in motility, presence of fimbriae, extra‐cellular polymeric substances, surface charge, hydrophobicity and membrane fluidity. The phenolic combination reduced 26–51% of motility, 1 log CFU per cm2 of adhered bacteria and 20–40% the carbohydrate and protein content in the biofilm matrix. Curli fimbriae, surface charge and cell hydrophobicity were affected to a greater extent by the phenolic combination. In the mixture, vanillic acid was the most effective for reducing bacterial adhesion, extra‐polymeric substance production, motility, curli fimbriae and biofilm structure. Notwithstanding, protocatechuic acid caused major changes in the bacterial cell surface properties, whereas catechin affected the cell membrane functionality. Conclusion: Catechin, protocatechuic and vanillic acids have different bacterial cell targets, explaining the synergistic effect of their combination against uropathogenic E. coli. Significance and Impact of Study: This study shows the contribution of catechin, protocatechuic and vanillic acids in producing a synergistic mixture against the adhesion of uropathogenic E. coli on silicone catheters. The action of catechin, vanillic and protocatechuic acids included specific contributions of each compound against the E. coli membrane's integrity, motility, surface properties and production of extracellular polymeric substances. Therefore, the studied mixture of phenolic compounds could be used as an antibiotic alternative to reduce urinary tract infections associated with silicone catheters. [ABSTRACT FROM AUTHOR]

Ectropis obliqua Prout is the main pest of the tea plant Camellia sinensis (L.) O. Kuntze in China, affecting an annual area of more than one million acres. (−)-Epigallocatechin-3-gallate (EGCG) is the major catechin in tea leaves. Here, we show that EGCG is highly efficient in increasing the survival rate of E. obliqua larvae. We also compared the gut peroxidase (PO) activity between EGCG-fed and control larvae. EGCG-fed larvae had significantly greater PO activity levels than control larvae. Western blotting validated these results. Gut PO activity levels of larvae fed an artificial diet gradually decreased and disappeared completely by day 5. We hypothesize that the increased survival rate of EGCG-fed larvae was associated with increased PO activity. This research provides evidence that E. obliqua larvae have adapted to, and may even benefit from, secondary compounds found in tea leaves. [ABSTRACT FROM AUTHOR]

Aims: The aim of the study was to check whether two flavanols ((−)‐epigallocatechin gallate and (+)‐catechin) can ameliorate oxidative stress (OS) accompanying and contributing to the lethal effects of heating (50°C) and freezing‐thawing on the yeast Saccharomyces cerevisiae. Methods and Results: The flavanols studied increased yeast survival during heating and freezing‐thawing, estimated by the colony forming assay. They improved also such indices of OS as increased production of reactive oxygen species, decrease of total antioxidant activity of yeast cell extracts and increase in the level of protein carbonyls. Conclusions: Amelioration of OS by flavanols increases the survival of the yeast subjected to high temperature and freezing‐thawing. Significance and Impact of the Study: Flavanols may be considered as means of enhancing yeast survival under extreme temperature conditions and probably in other conditions involving OS. [ABSTRACT FROM AUTHOR]

The gingival epithelium, a stratified squamous tissue that acts as an interface between the external environment and the underlying connective tissue, plays an active role in maintaining periodontal health. The aim of the present study was to investigate the ability of green tea catechins to enhance gingival epithelial barrier function and protect against the disruption of epithelial integrity induced by Porphyromonas gingivalis. Both the green tea extract and epigallocatechin-3-gallate (EGCG) dose- and time-dependently increased the transepithelial electrical resistance (TER) of a gingival keratinocyte model and decreased the permeability of the cell monolayer to fluorescein isothyocyanate-conjugated 4.4-kDa dextran. This was associated with the increased expression of zonula occludens-1 (ZO-1) and occludin, two tight junction proteins. Treating the gingival keratinocyte monolayer with P. gingivalis caused a reduction in TER and affected the distribution of ZO-1 and occludin, allowing P. gingivalis to translocate through the cell monolayer. These deleterious effects mediated by P. gingivalis were abolished by the green tea extract and EGCG. This protection may be in part related to the ability of tea catechins to inhibit the protease activities of P. gingivalis. Given the above properties, green tea catechins may represent promising preventive and therapeutic molecules against periodontal disease. [ABSTRACT FROM AUTHOR]

Inhibition of excessive fructose intake in the small intestine could alleviate fructose-induced diseases such as hypertension and non-alcoholic fatty liver disease. We examined the effect of phytochemicals on fructose uptake using human intestinal epithelial-like Caco-2 cells which express the fructose transporter, GLUT5. Among 35 phytochemicals tested, five, including nobiletin and epicatechin gallate (ECg), markedly inhibited fructose uptake. Nobiletin and ECg also inhibited the uptake of glucose but not of L-leucine or Gly-Sar, suggesting an inhibitory effect specific to monosaccharide transporters. Kinetic analysis further suggested that this reduction in fructose uptake was associated with a decrease in the apparent number of cell-surface GLUT5 molecules, and not with a change in the affinity of GLUT5 for fructose. Lastly, nobiletin and ECg suppressed the permeation of fructose across Caco-2 cell monolayers. These findings suggest that nobiletin and ECg are good candidates for preventing diseases caused by excessive fructose intake. [ABSTRACT FROM AUTHOR]

Abstract: The present study was undertaken to determine the mechanism of antibacterial activity of a polyphenolic fraction, composed of mainly catechin and isorhamnetin, previously isolated from Kombucha, a 14‐day fermented beverage of sugared black tea, against the enteropathogen Vibrio cholerae N16961. Bacterial growth was found to be seriously impaired by the polyphenolic fraction in a dose‐dependent manner. Scanning Electron Microscopy demonstrated morphological alterations in bacterial cells when exposed to the polyphenolic fraction in a concentration‐dependent manner. Permeabilization assays confirmed that the fraction disrupted bacterial membrane integrity in both time‐ and dose‐dependent manners, which were proportional to the production of intracellular reactive oxygen species (ROS). Furthermore, each of the polyphenols catechin and isorhamnetin showed the ability to permeate bacterial cell membranes by generating oxidative stress, thereby suggesting their role in the antibacterial potential of Kombucha. Thus, the basic mechanism of antibacterial activity of the Kombucha polyphenolic fraction against V. cholerae involved bacterial membrane permeabilization and morphological changes, which might be due to the generation of intracellular ROS. To the best of our knowledge, this is the first report on the investigation of antibacterial mechanism of Kombucha, which is mostly attributed to its polyphenolic content. Significance and Impact of the Study: The emergence of multidrug‐resistant Vibrio cholerae strains has hindered an efficient anti‐Vibrio therapy. This study has demonstrated the membrane damage‐mediated antibacterial mechanism of Kombucha, a popular fermented beverage of sugared tea, which is mostly attributed to its polyphenolic content. This study also implies the exploitation of Kombucha as a potential new source of bioactive polyphenols against V. cholerae. [ABSTRACT FROM AUTHOR]

Abstract: The total direct count (TDC) microbial enumeration method is rapid and suitable for analysing environmental samples containing numerous un‐culturable micro‐organisms. Conventional TDC methods require the addition of a fluorescent stain and are thus unsuitable for automatic monitoring. We unexpectedly found that heated micro‐organisms emit strong autofluorescence. This study was conducted to determine how heating enhances the autofluorescence of bacteria and fungi and to evaluate whether the phenomenon could be exploited to develop a new TDC method. Bacterial autofluorescence was augmented by heating cells at 200°C. ELISA results indicated that levels of advanced glycation end products (AGEs) increased in heated microbes. Catechin, an inhibitor of the Maillard reaction, disrupted the intensification of autofluorescence. These results suggest that the enhanced autofluorescence is associated with the formation of AGEs and that the reaction could be utilized as alternative probe in TDC methods. Significance and Impact of the Study: Autofluorescence of bacteria and fungi was prominently intensified by heat treatment at 200°C. This phenomenon was associated with advanced glycation end products formed in micro‐organisms via the Maillard reaction. The fluorescence signal was strong enough to be utilized as an alternative probe for fluorescent dye in the total direct count method. This phenomenon could be incorporated in an automatic apparatus for microbial enumeration, as it does not require staining. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate how dietary supplementation of tea polyphenols (TP) and tea catechins (TC) affect laying performance, albumen quality, ovomucin composition, and magnum morphology of laying hens in the late phase of production. Two hundred seventy Hy-Line Brown laying hens (64 wk old) were assigned to a basal diet (the control), the basal diet supplemented with 200 mg/kg tea polyphenols (TP200) or 200 mg/kg tea catechins (TC200). Each treatment had 6 replicates with 15 hens each. The feeding trial lasted 10 wks. Over the course of the trial, dietary supplementation with TP200 significantly increased the egg production (EP) and improved the feed conversion ratio (FCR) in wk 6 to 10 and wk 1 to 10 (P < 0.05). The albumen height and the Haugh unit (HU) of hens fed TP200 were higher than those of hens fed the control diet at wks 8 and 10 (P < 0.05). However, there were no significant differences in the albumen height and the HU between the TP200 and TC200 groups (P > 0.05). The SDS-PAGE analysis indicated that bands of the ovomucin fractions in the TP200 group had the highest intensity compared with those of the control and TC200 groups. Compared with the control, there was a significant increase in protein sulfhydryl (SH) content of the albumen in the TP200 group at the end of experiment, while a significant decrease in protein carbonyl content and protein surface hydrophobicity (P < 0.05). There were also obvious increase in the height and width of the primary folds, epithelial cell height, and cilia height of the simple columnar epithelium in the TP200 group compared with the control and TC200 groups (P < 0.05). In conclusion, dietary supplementation with 200 mg/kg TP can improve performance, albumen quality, and magnum morphology of aged hens. In addition, TP rather than TC could improve the health status of the magnum for aged layers. [ABSTRACT FROM AUTHOR]

Objectives Possible interaction of green tea beverage ( GT) containing cyclodextrins and high concentration catechins, a drinking water, with P-glycoprotein (P-gp) substrates was examined in vitro and in vivo. Methods Effects of GT on the uptake of rhodamine 123 by LLC- GA5- COL150 cells and intestinal efflux of rhodamine 123 from blood, intestinal absorption of quinidine from ileum loop and oral absorption of digoxin were examined in rats. Effects of GT and GT components on digoxin solubility were also examined. Key findings Green tea increased the uptake of rhodamine 123 by LLC- GA5- COL150 cells, suppressed the intestinal efflux of rhodamine 123 from blood and increased the absorption of quinidine in the ileum of rats. Also, GT increased the solubility of digoxin, and ingestion of GT significantly increased the oral absorption of digoxin given at a high dose in rats. Conclusions Green tea suppressed the P-gp-mediated efflux transport of hydrophilic compounds and increased the solubility of lipophilic compounds. Thus, GT may cause interaction with various P-gp substrates, due to the combined effects of catechins and cyclodextrins. Especially, cyclodextrin alone can cause interaction with various low-solubility compounds in vivo. In taking low-solubility drugs including low-solubility P-gp substrates, cyclodextrin-containing foods and beverages such as GT should be avoided. [ABSTRACT FROM AUTHOR]

Black tea infusions are one of the most popular beverages across the world. Their extract composition depends on several factors, brewing time being one of the most important determinants. The aim of the present study was to determine the catechin composition of different black tea infusions using a validated LC electrospray ionization time-of-flight MS method. Additionally, total phenolic content (TPC) and antioxidant activity of infusions were evaluated using Folin-Ciocalteu reagent and stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). An optimized LC-MS method enabled the precise identification of the studied catechins [epicatechin (EC), EC gallate (ECG), epigallocatechin (EGC), and epigallocatechin-3-gallate (EGCG)] and gallic acid (GA). The major catechin in all investigated teas was EGC (25.6 mg/100 cm³ after 4 min of brewing). EC was present at the lowest concentration in all extracts. TPC and antiradical scavenging activity were in a good agreement with catechins and GA content. In general, the longer the brewing time, the higher the concentration of catechin, TPC, and antioxidant activity values. However, it should be noted that after 2 min brewing, most phenolics had already been extracted, and extract composition did not significantly change at a prolonged extraction time. [ABSTRACT FROM AUTHOR]

Atherosclerosis is one of the diseases related to metabolic syndrome which is caused by obesity. Previous reports have shown that green tea and its components have anti-obesity effect. We examined whether catechins and caffeine can prevent the development of atherosclerosis by oral administration, singly or in combination to the atherosclerosis model mice. Results demonstrated that the number of atherosclerotic regions in the aorta was significantly reduced by the combined treatment, and the atherosclerotic area was also improved. Serum HDL-C increased by caffeine single treatment, but no effect on the TG and TC by any treatments. Moreover, ECG illuviated to atheromatous lesions in aorta and the illuviation was enhanced by caffeine. The mRNA expression levels of LOX-1 and TNF-α showed a tendency to suppress by the combined treatment. These results indicated that the combined administration of catechins and caffeine has the inhibitory effect on the development of atherosclerosis in mice. Our research clearly demonstrated that the combined treatment of catechins and caffeine showed the inhibitory effect on the development of atherosclerosis in mice. [ABSTRACT FROM PUBLISHER]

This study characterized the enzymatic ability of a cell-free extract from an acidophilic (+)-catechin degraderBurkholderia oxyphila(OX-01). The crude OX-01 extracts were able to transform (+)-catechin and (−)-epicatechin into (+)-taxifolin via a leucocyanidin intermediate in a two-step oxidation. Enzymatic oxidation at the C-4 position was carried out anaerobically using H2O as an oxygen donor. The C-4 oxidation occurred only in the presence of the 2R-catechin stereoisomer, with the C-3 stereoisomer not affecting the reaction. These results suggest that the OX-01 may have evolved to target both (+)-catechin and (−)-epicatechin, which are major structural units in plants. Proposed anaerobic oxidation pathway of (+)-catechin and (−)-epicatechin byBurkholderia oxyphilaOX-01. [ABSTRACT FROM PUBLISHER]

Vivabon syrup is a balanced composition of dietary ingredients of phytopharmaceutical nature for maintaining the physique, vigor, vitality and balanced growth of children. The herbal ingredients of pediatric syrup are rich in bioflavonoid, proteins, vitamins, glycosides and trace elements. Vivabon is formulated with herbal drugs such as Phoenix sylvestris, Emblica officinalis, Withania somnifera, Centella asiatica, Amomum subulatum, Zingiber officinalis, Trigonella foenum-graecum, Centaurea behen and Piper longum. Catechins are flavan-3-ols that are found widely in the medicinal herbs and are utilized for anti-inflammatory, cardio protective, hepato-protective, neural protection and other biological activities. In general, the dietary intake of flavonoids has been regarded traditionally as beneficial for body growth. Standardization of Vivabon syrup dosage form using HPLC/DAD has been developed for quantitative estimation of Catechin as a chemical marker. The method was validated as per ICH guidelines. Validation studies demonstrated that the developed HPLC method is quite distinct, reproducible aswell as quick and fast. The relatively high recovery and lowcomparable standard deviation confirm the suitability of the developed method for the determination of Catechin in syrup. [ABSTRACT FROM AUTHOR]

Galloylated catechins and flavonol 3-O-glycosides are characteristic astringent taste compounds in tea (Camellia sinensis). The mechanism involved in the formation of these metabolites remains unknown in tea plants. In this paper, 178 UGT genes (CsUGTs) were identified in C. sinensis based on an analysis of tea transcriptome data. Phylogenetic analysis revealed that 132 of these genes were clustered into 15 previously established phylogenetic groups (A to M, O and P) and a newly identified group R. Three of the 11 recombinant UGT proteins tested were found to be involved in the in vitro biosynthesis of β-glucogallin and glycosylated flavonols. CsUGT84A22 exhibited catalytic activity toward phenolic acids, in particular gallic acid, to produce β-glucogallin, which is the immediate precursor of galloylated catechin biosynthesis in tea plants. CsUGT78A14 and CsUGT78A15 were found to be responsible for the biosynthesis of flavonol 3-O-glucosides and flavonol 3-O-galactosides, respectively. Site-directed mutagenesis of the Q373H substitution for CsUGT78A14 indicated that the Q (Gln) residue played a catalytically crucial role for flavonoid 3-O-glucosyltransferase activity. The expression profiles of the CsUGT84A22, CsUGT78A14, and CsUGT78A15 genes were correlated with the accumulation patterns of β-glucogallin and the glycosylated flavonols which indicated that these three CsUGT genes were involved in the biosynthesis of astringent compounds in C. sinensis. [ABSTRACT FROM AUTHOR]

Isoflavone-metabolizing bacteria,Adlercreutzia equolifaciens,Asaccharobacter celatus,Slackia equolifaciens,andSlackia isoflavoniconvertenscatalyzed C-ring cleavage of (–)-epicatechin and (+)-catechin, (+)-epicatechin, and (–)-catechin in varying degrees. The cleaving abilities of (–)-epicatechin and (+)-catechin were enhanced by hydrogen, except (+)-catechin cleavage byS. equolifaciens, which was not accelerated. (−)-Catechin cleavage byAd. equolifacienswas remarkably accelerated by hydrogen. [ABSTRACT FROM PUBLISHER]

The article offers information on the Standard Method Performance Requirements (SMPRs®) by the Association of Official Analytical Chemists (AOAC) for identification of methyl xanthines, theaflavins, and catechins in tea (Camellia sinensis) dietary supplements and ingredients. Topics mentioned include the importance of tea dietary ingredients, the chemical structures for catechins and theaflavins, and the green tea analysis.

The aim of the study was to compare the antimicrobial activities of freshly made, heat-treated (HT) and 14 day stored (+)-Catechin solutions with (+)-catechin flavanol isomers in the presence of copper sulphate. (+)-Catechin activity was investigated when combined with different ratios of Cu2+; 100°C heat treatment; autoclaving; and 14 day storage against Staphylococcus aureus. Cu2+-(+)-Catechin complexation, isomer structure-activity relationships, and H2O2 generation were also investigated. Freshly made, HT, and 14 day stored flavanols showed no activity. While combined Cu2+-autoclaved (+)-Catechin and -HT(+)-Catechin activities were similar, HT(+)-Catechin was more active than either freshly made (+)-catechin (generating more H2O2) or (−)-Epicatechin (though it generated less H2O2) or 14 day-(+)-Catechin (which had similar activity to Cu2+ controls-although it generated more H2O2). When combined with Cu2+, in terms of rates of activity, HT(+)-Catechin was lower than (−)-Epigallocatechin gallate and greater than freshly made (+)-Catechin. Freshly made and HT(+)-Catechin formed acidic complexes with Cu2+ as indicated by pH and UV-vis measurements although pH changes did not account for antimicrobial activity. Freshly made and HT(+)-Catechin both formed Cu2+ complexes. The HT(+)-Catechin complex generated more H2O2 which could explain its higher antimicrobial activity. Significance and Impact of the Study Natural products attract considerable attention in the search for novel antimicrobials, prebiotics and antioxidants. Enhanced biological activity of natural products has been demonstrated with chemical and heat treatment. This article extends the few publications on heat treatments of plant products and combinations with adjuncts, to raise antimicrobial activity against pathogens such as Staphylococcus aureus. We demonstrated that heat treatment could increase the activity of (+)-Catechin, a weak antimicrobial flavanol found commonly in plants in the presence of copper sulphate. Heat treatment of readily available resources merits consideration in the development of more potent substances for use in clinical settings and agriculture. [ABSTRACT FROM AUTHOR]

The article discusses a study investigating the effect of theaflavins (TFs) on membrane barrier of Caco-2 cells. Topics discussed include enhancement of intestinal barrier of Caco-2, human colon epithelial cancer cell line, monolayers by increasing the expression of AMP(adenosine monophosphate)-activated protein kinase (AMPK)-mediated occludin, physiological role of TFs on the intestinal transport system, and association between epithelial AMPK activation with enhanced tight junctions (TJ).

The sensation of astringency is elicited by catechins and their polymers in wine and tea. It has been considered that catechins in green tea are unstable and auto-oxidized to induce more astringent taste. Here, we examined how mammalian transient receptor potential V1 (TRPV1) and TRPA1, which are nociceptive sensors, are activated by green tea catechins during the auto-oxidation process. Neither TRPV1 nor TRPA1 could be activated by any of the freshly prepared catechin. When one of the major catechin, epigallocatechin gallate (EGCG), was preincubated for 3h in Hank’s balanced salt solution, it significantly activated both TRP channels expressed in HEK293 cells. Even after incubation, other catechins showed much less effects. Results suggest that only oxidative products of EGCG activate both TRPV1 and TRPA1. Dorsal root ganglion (DRG) sensory neurons were also activated by the incubated EGCG through TRPV1 and TRPA1 channels. Liquid chromatography-mass spectrometry revealed that theasinensins A and D are formed during incubation of EGCG. We found that purified theasinensin A activates both TRPV1 and TRPA1, and that it stimulates DRG neurons through TRPV1 and TRPA1 channels. Results suggested a possibility that TRPV1 and TRPA1 channels are involved in the sense of astringent taste of green tea. [ABSTRACT FROM PUBLISHER]

An electrochemical technique for the determination of catechin, protocatechuic acid, and L-lactic acid has been developed using ferroceneboronic acid (FBA) as an electrochemical probe. The principle is based on the changes in voltammograms of FBA associated with selective binding of the analytes to FBA. A cyclic voltammogram and a differential pulse voltammogram (DPV) of FBA were recorded on a glassy carbon electrode in the presence of the analytes. The oxidation or reduction peak currents of FBA were decreased in the presence of the analytes, depending on their concentrations. The DPV measurements provided useful calibration graphs in the concentration range of 0.5-4.0 x 10-3 M catechin, 0.1-1.2 x 10-5 M protocatechuic acid, and 0.5-40 x 10-5 M L-lactic acid. The proposed method was successfully applied to the analysis of catechin in abdominal pain water medicine. [ABSTRACT FROM AUTHOR]

A high-performance liquid chromatography method employing diode array detection was developed to determine levels of the major catechins, proanthocyanidin (procyanidin B2), caffeine, thymoquinone and carvacrol and its isomer, thymol, which are present in different natural complex matrices found in commercial products of Camellia sinensis L. and/or Nigella sativa L. Reversed-phase separation was performed on a C18 column by using gradient elution by varying the proportions of solvent A (distilled water containing 0.05% orthophosphoric acid) and solvent B (acetonitrile), with a flow rate of 1.5 mL/min and duration of 31 min. Excellent linearity was observed for all standard calibration curves, and correlation coefficients were above 0.9996. The developed method is efficient, with high reproducibility and sensitivity, and is ideally suited for rapid and routine analysis of principal components in these promising medicinal plants. [ABSTRACT FROM PUBLISHER]

Aims The aim of this study was to investigate the effects of tea catechin epigallocatechin gallate ( EGCg) on established biofilms and biofilm formation by Porphyromonas gingivalis, a major pathogen of periodontal disease. Methods and Results Biofilm cell survival was measured using adenosine triphosphate ( ATP) bioluminescence. In the presence of EGCg, the ATP level in cells of established biofilms was significantly decreased compared to the controls ( P < 0·0001). Transmission electron microscopy revealed that EGCg damaged the cell membrane and cell wall of P. gingivalis. Confocal laser-scanning microscopy revealed that the proportion of dead cells was higher in biofilms treated with EGCg. Moreover, the effects of subminimal inhibitory concentrations ( MICs) of EGCg on P. gingivalis biofilm formation were dose-dependent ( P < 0·0001). Conclusion Our results suggest that EGCg destroys established P. gingivalis biofilms and inhibits biofilm formation. Significance and Impact of the Study Development of chemical control agents against oral biofilms is necessary, because oral biofilms can be only removed using mechanical debridement. This article indicates that EGCg may represent a novel antibiofilm agent that prevents infections involving bacterial biofilms such as periodontitis. [ABSTRACT FROM AUTHOR]

Single-laboratory validation data previously published in the Journal of AOAC INTERNATIONAL 95(2), 500-507 (2012) was reviewed by the Stakeholder Panel on Strategic Food Analytical Methods Expert Review Panel (ERP) at the AOAC INTERNATIONAL Mid-Year Meeting held on March 12-14, 2013 in Rockville, MD. The ERP determined the data presented met the established standard method performance requirement and approved the method as AOAC Official First Action on March 14, 2013. Using high-performance liquid chromatography (HPLC), flavanol enantiomers, (+)- and (-)-epicatechin and (+)- and (-)-catechin, are eluted isocratically using ammonium acetate and methanol mobile phase. The mobile phase is applied to a modified ß-cyclodextrin chiral stationary phase and the flavanols detected by fluorescence. Using several cocoa-based matrices, recoveries for the four enantiomers ranged from 82.2-102.1% at a 50% spike level, and 80.4-101.1% at a 100% spike level. Precision was determined to be 1.46-3.22% for (-)-epicatechin, 3.66-6.90% for (+)-catechin, 1.69-6.89% for (-)-catechin. (+)-Epicatechin was not detected in any of the samples used for this work, so precision could not be determined for this molecule. [ABSTRACT FROM AUTHOR]

Background and Aims Condensed tannins (also called proanthocyanidins) are widespread polymers of catechins and are essential for the defence mechanisms of vascular plants (Tracheophyta). A large body of evidence argues for the synthesis of monomeric epicatechin on the cytosolic face of the endoplasmic reticulum and its transport to the vacuole, although the site of its polymerization into tannins remains to be elucidated. The aim of the study was to re-examine the cellular frame of tannin polymerization in various representatives of the Tracheophyta. Methods Light microscopy epifluorescence, confocal microscopy, transmission electron microscopy (TEM), chemical analysis of tannins following cell fractionation, and immunocytochemistry were used as independent methods on tannin-rich samples from various organs from Cycadophyta, Ginkgophyta, Equisetophyta, Pteridophyta, Coniferophyta and Magnoliophyta. Tissues were fixed in a caffeine–glutaraldehyde mixture and examined by TEM. Other fresh samples were incubated with primary antibodies against proteins from both chloroplastic envelopes and a thylakoidal chlorophyll-carrying protein; they were also incubated with gelatin–Oregon Green, a fluorescent marker of condensed tannins. Coupled spectral analyses of chlorophyll and tannins were carried out by confocal microscopy on fresh tissues and tannin-rich accretions obtained through cell fractionation; chemical analyses of tannins and chlorophylls were also performed on the accretions. Key Results and Conclusions The presence of the three different chloroplast membranes inside vacuolar accretions that constitute the typical form of tannin storage in vascular plants was established in fresh tissues as well as in purified organelles, using several independent methods. Tannins are polymerized in a new chloroplast-derived organelle, the tannosome. These are formed by pearling of the thylakoids into 30 nm spheres, which are then encapsulated in a tannosome shuttle formed by budding from the chloroplast and bound by a membrane resulting from the fusion of both chloroplast envelopes. The shuttle conveys numerous tannosomes through the cytoplasm towards the vacuole in which it is then incorporated by invagination of the tonoplast. Finally, shuttles bound by a portion of tonoplast aggregate into tannin accretions which are stored in the vacuole. Polymerization of tannins occurs inside the tannosome regardless of the compartment being crossed. A complete sequence of events apparently valid in all studied Tracheophyta is described. [ABSTRACT FROM AUTHOR]

A rapid method has been developed to quantify seven catechins and caffeine in green tea (Camillia sinensis) raw material and powdered extract, and dietary supplements containing green tea extract. The method utilizes RP HPLC with a phenyl-based stationary phase and gradient elution. Detection is by UV absorbance. The total run time, including column re-equilibration, is 13 min. Single-laboratory validation (SLV) has been performed on the method to determine the repeatability, accuracy, selectivity, LOD, LOQ, ruggedness, and linearity for (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, (-)-epigallocatechin, (-)-gallocatechin gallate, (-)-epigallocatechin gallate, and (+)-gallocatechin, as well as caffeine. Repeatability precision and recovery results met AOAC guidelines for SLV studies for all catechins and caffeine down to a level of approximately 20 mg/g. Finished products containing high concentrations of minerals require the use of EDTA to prevent decomposition of the catechins. [ABSTRACT FROM AUTHOR]

The article discusses a study on peanut-skin polyphenol including epicatechin (4β;→6)-epicatechin-(2β;→O→7,4β→8)-catechin (EEC) which shows cholesterol micelle-degrading effect. It compares EEC with polyphenol procyanidin A1. The study revealed that administration of water-soluble peanut-skin polyphenol fraction improved hypercholesterolemia in rats fed with a high-cholesterol diet.

The article presents a study which describes the bioconversion and extraction efficiency of catechins following commercial enzyme treatments. It cites several methods used including hydrolysis of green tea extracts with commercially prepared enzymes, statistical analysis, and tannase hydrolysis. The study reveals the efficacy of Viscozyme of the Aspergillus specie (sp.) among other commercial enzymes that were tested.

Proanthocyanidins (PAs) are products of the flavonoid pathway, which also leads to the production of anthocyanins and flavonols. Many flavonoids have antioxidant properties and may have beneficial effects for human health. PAs are found in the seeds and fruits of many plants. In apple fruit (Malus × domestica Borkh.), the flavonoid biosynthetic pathway is most active in the skin, with the flavan-3-ols, catechin, and epicatechin acting as the initiating units for the synthesis of PA polymers. This study examined the genes involved in the production of PAs in three apple cultivars: two heritage apple cultivars, Hetlina and Devonshire Quarrenden, and a commercial cultivar, Royal Gala. HPLC analysis shows that tree-ripe fruit from Hetlina and Devonshire Quarrenden had a higher phenolic content than Royal Gala. Epicatechin and catechin biosynthesis is under the control of the biosynthetic enzymes anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR1), respectively. Counter-intuitively, real-time quantitative PCR analysis showed that the expression levels of Royal Gala LAR1 and ANR were significantly higher than those of both Devonshire Quarrenden and Hetlina. This suggests that a compensatory feedback mechanism may be active, whereby low concentrations of PAs may induce higher expression of gene transcripts. Further investigation is required into the regulation of these key enzymes in apple.Abbreviations:ANOVAanalysis of varianceANRanthocyanidin reductaseDADdiode array detectorDAFBdays after full bloomDFRdihydroflavonol reductaseLARleucoanthocyanidin reductaseLC-MSliquid chromatography/mass spectrometryPAproanthocyanidinqPCRreal-time quantitative PCR [ABSTRACT FROM AUTHOR]

The article evaluates the antiviral properties of green tea catechins on development of hand washing disinfectant solutions which can acts against viral transmission among humans. It mentions weakening of the virus present on the skin cell layers contact model for influenza virus transmission on washing with green tea solution. The combinational effects of green tea and antioxidants which increases the antiviral activity and shelf-life of a green tea-based hand washing solution is also analyzed.

The article discusses a single-laboratory validation study for a high-performance liquid chromatography (HPLC) method to identify and quantify the flavanol enantiomers catechin and epicatechin in cocoa-based ingredients and products. Epicatechin was found to be the predominant flavanol and represented 68-91% of the total monomeric flavanols detected in all the samples analyzed. Recoveries for the samples investigated are also noted.

A characteristic astringent taste is elicited by polyphenols. Among the polyphenols, catechins and their polymers are the most abundant polyphenols in wine and tea. A typical green tea polyphenol is epigallocatechin gallate (EGCG). Currently, the mechanism underlying the sensation of astringent taste is not well understood. We observed by calcium imaging that the mouse intestinal endocrine cell line STC-1 responds to the astringent compound, EGCG. Among major catechins of green tea, EGCG was most effective at eliciting a response in this cell line. This cellular response was not observed in HEK293T or 3T3 cells. Further analyses demonstrated that the 67-kDa laminin receptor, a known EGCG receptor, is not directly involved. The Ca2+ response to EGCG in STC-1 cells was decreased by inhibitors of the transient receptor potential A1 (TRPA1) channel. HEK293T cells transfected with the mouse TRPA1 (mTRPA1) cDNA showed a Ca2+ response upon application of EGCG, and their response properties were similar to those observed in STC-1 cells. These results indicate that an astringent compound, EGCG, activates the mTRPA1 in intestinal STC-1 cells. TRPA1 might play an important role in the astringency taste on the tongue. [ABSTRACT FROM AUTHOR]

Long-term exposure to low doses of environmental carcinogens contributes to sporadic human breast cancers. Epidemiologic and experimental studies indicate that green tea catechins (GTCs) may intervene with breast cancer development. We have been developing a chronically induced breast cell carcinogenesis model wherein we repeatedly expose non-cancerous, human breast epithelial MCF10A cells to bioachievable picomolar concentrations of environmental carcinogens, such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and benzo[a]pyrene (B[a]P), to progressively induce cellular acquisition of cancer-associated properties, as measurable end points. The model is then used as a target to identify non-cytotoxic preventive agents effective in suppression of cellular carcinogenesis. Here, we demonstrate, for the first time, a two-step strategy that initially used end points that were transiently induced by short-term exposure to NNK and B[a]P as targets to detect GTCs capable of blocking the acquisition of cancer-associated properties and subsequently used end points constantly induced by long-term exposure to carcinogens as targets to verify GTCs capable of suppressing carcinogenesis. We detected that short-term exposure to NNK and B[a]P resulted in elevation of reactive oxygen species (ROS), leading to Raf-independent extracellular signal-regulated kinase (ERK) pathway activation and subsequent induction of cell proliferation and DNA damage. These GTCs, at non-cytotoxic levels, were able to suppress chronically induced cellular carcinogenesis by blocking carcinogen-induced ROS elevation, ERK activation, cell proliferation and DNA damage in each exposure cycle. Our model may help accelerate the identification of preventive agents to intervene in carcinogenesis induced by long-term exposure to environmental carcinogens, thereby safely and effectively reducing the health risk of sporadic breast cancer. [ABSTRACT FROM AUTHOR]

Reducing chemical use for suppressing internal and external parasites of livestock is essential for protecting environmental health. Although plant condensed tannins are known to suppress gastro-intestinal parasites in small ruminants, no research on the effects of tannins on external arthropod populations such as the house fly, Musca domestica L., have been conducted. We examined the impact of plant material containing condensed tannins on house fly development. Prairie acacia (Acacia angustissima (Mill.), Kuntze variety hirta (Nutt.) B.L. Rob.) herbage, panicled tick-clover (Desmodium paniculatum (L.) DC.) herbage, and quebracho (Shinopsis balansae Engl.) extracts were introduced at rates of 1, 3 or 5% condensed tannins/kg beef cattle, dairy cattle, and goat manure, respectively. In a second experiment, we also introduce purified catechin at 1 or 3% of dairy manure dry matter and measured its impact on house fly development. For the house flies used in these experiments, the following was recorded: percent fly emergence (PFE), average daily gain (ADG), and average fly weight (AFW). No effects (P > 0.05) in house fly development were measured in the caprine manure. Prairie acacia (20.9% condensed tannins) had no effect on house flies developing in either bovine manures. Tick clover (4.9% condensed tannins) had a negative effect on all three quantifiable variables of house fly development in the bovine manures, whereas quebracho extract (64.0% condensed tannins) at the 3 and 5% rate reduced fly emergence in beef manure and average daily gain in dairy manure. The application of purified catechin at 3%, but not 1%, reduced fly PFE, ADG, and AFW. [ABSTRACT FROM AUTHOR]

Objectives Previously, the flavonoid (±)-catechin was shown to exert potent neuroprotective action in the mouse 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease model. The purpose of this study was to investigate whether the different enantiomers of catechin ((+)-catechin, (−)-catechin and (±)-catechin, a 50 : 50 mixture of (+)-catechin and (−)-catechin) could protect SH-SY5Y cells against 1-methyl-4-phenylpyridinium ion (MPP+) toxicity by decreasing the generation of oxygen free radicals. The inhibitive effect of (±)-catechin on JNK/c-Jun activation was investigated. Methods The effects of (+)-catechin, (−)-catechin or (±)-catechin in protecting against MPP+ toxicity were evaluated and compared in SH-SY5Y cells by testing the release of lactate dehydrogenase. The generation of reactive oxygen species (ROS) was measured by immunochemistry and the phosphorylation level of JNK/c-Jun was determined by Western blotting. Key findings In SH-SY5Y cells, (+)-catechin, (−)-catechin or (±)-catechin reduced apoptosis induced by MPP+ and decreased ROS generation caused by MPP+. Different enantiomers of catechin showed protective effects at similar potency. Moreover (±)-catechin decreased JNK/c-Jun phosphorylation which was increased by MPP+. Conclusions Catechin and its two enantiomers could protect SH-SY5Y cells against MPP+ cytotoxicity at a similar potency. Antioxidative stress and inhibition of the JNK/c-Jun signalling pathway might have been involved in the neuroprotective mechanisms of catechin against MPP+ cytotoxicity in SH-SY5Y cells. [ABSTRACT FROM AUTHOR]