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The present study investigated the synergistic potential of methanol extract/fractions of Camellia sinensis (L.) Kuntze (CSM) leaves and orlistat on inhibition of Pancreatic Lipase (PL). Since PL is responsible for 50–70% of dietary fats digestion, its inhibition is considered as a promising target for the management of obesity. A synergy guided fractionation strategy has been incorporated with the help of combination index (CI) and isobologram methods. CSM exhibited a potential synergistic activity in combination with orlistat (CI value: 0.66). Amongst the subfractions of CSM, polyphenol-rich fraction exhibited a greater synergistic potential (CI-0.35) than remaining fractions. HPLC analysis identified epicatechin gallate (ECG) and epigallocatechin gallate (EGCG) as major phytochemicals in polyphenol-rich fraction and the most active subfractions (F6 and F7). Two drug and three-drug combinations of these phytochemicals were investigated by partnering with orlistat. The three-drug combination (orlistat-EGCG-ECG) exhibited a greater synergistic potential (CI value-0.17) than the two-drug combinations of EGCG-orlistat and ECG-orlistat (CI values of 0.40 & 0.71, respectively). The resultant orlistat-EGCG-ECG combination resulted in a 12.11-fold dose reduction index for orlistat. Thus, synergistic drug combinations of polyphenol-rich fraction along with orlistat offers the prospect to enhance the orlistat anti-obesity efficacy in a decreased dose level, that will help to reduce its associated toxicities while maintaining its efficacy.

In this study, active and intelligent packaging films were developed by incorporating polypheol-rich pomegranate flesh extract (PFE) or pomegranate peel extract (PPE) into κ-carrageenan matrix. The structural, physical, pH-sensitive, antioxidant and antimicrobial properties of κ-carrageenan-PFE and κ-carrageenan-PPE films were compared for the first time. Results showed PFE was composed of cyanidin-3-O-glucoside (49.76%), peonidin-3-O-(6-malon)-glucoside (9.61%), malvidin-3-O-(6-acetyl)-glucoside (14.89%), pelargonidin-3-O- (6″-ethylmalonyl)-glucoside (7.05%), pelargonidin-3-O-(6-acetyl)-glucoside (9.51%) and isorhamnetin (9.18%). PPE was mainly composed of gallic acid (15.73%), malvidin-3-O-(6-acetyl)-glucoside (4.07%), epicatechin gallate (3.66%), luteolin (5.69%), vanillic acid (7.82%), caffeic acid (4.37%), punicalagin (39.96%) and ellagic acid (18.70%). The tensile strength, water vapor and UV light barrier ability of κ-carrageenan film were significantly promoted by the incorporation of PFE or PPE. Due to different polyphenolic compositions, κ-carrageenan-PPE films possessed higher UV light barrier, antioxidant and antimicrobial properties than κ-carrageenan-PFE films at the same extract incorporation levels. Nonetheless, κ-carrageenan-PFE films exhibited pH-sensitive property because of abundant anthocyanins in PFE. Notably, the physical and functional properties of κ-carrageenan-PFE and κ-carrageenan-PPE films were closely related to the content of extract. Our results suggested κ-carrageenan-PFE films could be further used as active and intelligent packaging, whereas κ-carrageenan-PPE films could be explored as active packaging in food industry.

This study selected common processing methods for orthodox black tea and investigated changes in the levels of Ne-(carboxymethyl)lysine (CML), Ne-(carboxyethyl)lysine (CEL), lysine, and polyphenols during each processing stage and using different parameters of each processing step. The effects of epicatechin gallate, epigallocatechin, epigallocatechin gallate, and gallic acid on the levels of CML, CEL, fructoselysine, glyoxal, and methylglyoxal were investigated by chemical model systems study under black tea processing conditions. In tea samples, CML and CEL levels significantly increased during drying (could reach 51.8 and 8.7 μg/g tea, respectively), while natural withering and extensive rolling and fermentation times facilitated the formation of CML and CEL by altering the substrate concentrations and the cellular structure of tea leaves to be dried. The results of model systems (containing lysine, glucose, and fructose) indicated that polyphenols were able to enhance the production of CML and CEL, and the levels of CML and CEL increased 1.2–3.2- and 1.6–3.5-fold, respectively. Furthermore, the main pathways responsible for CML and CEL formation during black tea processing likely involve fructoselysine and others but not glyoxal or methylglyoxal.

“Green waste” derived from food or agro-industrial has been applied to remove pathogenic bacteria. Green tea waste is polyphenol rich green waste but barely been focused by researchers. We ground the green tea wastes into superfine powder at 4 °C. The median particle size of superfine green tea powder (SGTP) was 9.215 μm. The chemical composition of powder was analyzed by high performance liquid chromatography (HPLC), and was mainly consisting of gallic acid (GA), epigallocatechin gallate (EGCG), caffeine (CAF), and epicatechin gallate (ECG). In vitro experiment indicated that the SGTP significantly inhibited bacterial proliferation of plant pathogen Ralstonia solanacearum GMI1000 in a concentration-dependent manner. However, when the hrpB deletion mutant of GMI1000 was inoculated in medium supplemented with SGTP, the bacterial growth was barely affected. Furthermore, the SGTP significantly decreased the bacterial swimming motility. Scanning electron microscope (SEM) image exhibited that cell damage emerged when bacteria was exposed to medium supplemented with SGTP. Antibacterial activity was compared towards SGTP, tea polyphenol, and tea extract, which suggested that SGTP had potential to be a functional antimicrobial. Our approach of SGTP as antimicrobial would broaden the scope of green waste utilization in a greener, cost-effective, and sustainable approach in future.

Catechins and methylxanthines are natural molecules in guarana (Paullinia cupana) that are associated with antioxidant and stimulatory effects in the human body. There are few natural sources of these antioxidants. The most popular molecule used in foods and beverages is caffeine, which, most of the time, is derived from synthetic sources. In this work, cold hydroalcoholic (CHM), hot hydroalcoholic (HHM), and aqueous enzymatic maceration (AEM) were applied to crude (CG) and waste guarana seeds (WG) to process these materials into natural added-value products with enhanced levels of catechin, epicatechin, epicatechin gallate, caffeine, theobromine and theophylline. The highest level of catechins and methylxanthines was extracted with HHM. Nevertheless, AEM enhanced the global yield in the extract, probably due to the solubilization of other substances. The maceration procedures applied to guarana contributed to the valorization of this plant crop by providing antioxidant sources with clear applications in food and nonfood industries.

In the present work, red grape seed and stalk extracts were incorporated in vesicular systems designed for topical application. The phytocomplexes were obtained by maceration of biomasses in ethanol and subsequent lyophilisation. Seed extract was rich in catechin, epicatechin, epicatechin gallate, while gallic acid, epigallocatechin gallate, quercetin, quercetin 3-glucoside and malvidin-3-glucoside were detected in higher amounts in the stalk extract. Both extracts were incorporated in liposomes, hyalurosomes and transfersomes. In addition, hyalo-transfersomes were developed for the first time in this work, by combining the main modifiers of hyalurosomes and transfersomes (i.e., sodium hyaluronate and tween 80, respectively). The mean diameter of the vesicles was ∼120 nm, and the zeta potential was strongly negative (∼67 mV), irrespective of the vesicle composition or the extract used. The antioxidant activity of the extracts, measured by the DPPH (2,2-Diphenyl-1-picrylhydrazyl) test, was ∼78%, and increased (∼86%) when loaded in the vesicles. Extract loaded vesicles were biocompatible with keratinocytes and fibroblasts, the main skin cells, and were able to protect the cells from oxidative damage and promote cell proliferation and migration at the wound site.

Common buckwheat achenes have high antioxidant activity due to their high phenol and especially flavonoid content. In general, the highest phenol contents in seeds is related to the seed coat layers. However, there is insufficient information about the composition of the individual parts of the buckwheat achene. The aim of this study was to determine the distribution and content of selected phenols within the individual parts of buckwheat achenes as well as the influence of soaking before hulling had on the phenol content. The seed coat was the part with the widest range of detected compounds, and also with the highest total content of phenolics from all groat parts. The seed coat was especially rich in epicatechin (257.60 mg/kg), procyanidin B2 (118.6 mg/kg), and epicatechin gallate (61.27 mg/kg). The embryo axis with the cotyledons is rich in rutin (283.37 mg/kg) and catechin (161.41 mg/kg). Contrary to groats, vanillic acid, vanillin, vitexin, quercitrin, and protocatechuic acid were detected in the buckwheat hulls. One-hour soaking of the achenes in tap water before dehulling caused a significant decrease (37%) in the content of phenolic compounds. The variety Spacinska had the highest level of identified phenolic compounds in the buckwheat hulls.

Biogenic amines (BAs) in fermented food products including fermented soybean paste, are of greatest safety concerns due to its potential toxicity. The current study aimed to develop methods to reduce BAs in fermented soybean paste by incorporating two different food additives (catechins and grapefruit seed extract) at different steps of manufacturing process and storage of soybean paste fermentation. High-performance liquid chromatography analysis of eight major BAs including histamine, putrescine, cadaverine, tyramine, tryptamine, β-phenylethylamine, spermine, and spermidine in fermented soybean paste was performed every 5 days for 30 days. The levels of Put and Cad decreased by 64% (24 μg/g), 60% (34 μg/g), 76% (43 μg/g) and 73% (37 μg/g), with the addition of 3 g/kg catechins (epicatechin, epicatechin gallate, epigallocatechin, and epigallocatechin gallate, respectively), before the koji fermentation step. With the addition of grapefruit seed extract (300 mg/kg) to soybean paste before storage, the greatest reduction was observed in putrescine level among the eight BAs. Current study suggests the use of natural food additives at different steps of fermented soybean paste manufacturing process, to determine the effect of food additives at each step of processing in reduction of BAs.

The antioxidant- and flavonoid-rich contents of red wine and green tea are reported to offer protection against cancer, cardiovascular disease, and diabetes. Some studies, however, show that flavonoids inhibit GLUT1-mediated, facilitative glucose transport, raising the possibility that their interaction with GLUT1 and subsequent downstream effects on carbohydrate metabolism may also impact health. The present study explores the structure–function relationships of flavonoid–GLUT1 interactions. We find that low concentrations of flavonoids act as cis-allosteric activators of sugar uptake, whereas higher concentrations competitively inhibit sugar uptake and noncompetitively inhibit sugar exit. Studies with heterologously expressed human GLUT1, -3, or -4 reveal that quercetin–GLUT1 and –GLUT4 interactions are stronger than quercetin–GLUT3 interactions, that epicatechin gallate (ECG) is more selective for GLUT1, and that epigallocatechin gallate (EGCG) is less GLUT isoform–selective. Docking studies suggest that only one flavonoid can bind to GLUT1 at any instant, but sugar transport and ligand-binding studies indicate that human erythrocyte GLUT1 can bind at least two flavonoid molecules simultaneously. Quercetin and EGCG are each characterized by positive, cooperative binding, whereas ECG shows negative cooperative binding. These findings support recent studies suggesting that GLUT1 forms an oligomeric complex of interacting, allosteric, alternating access transporters. We discuss how modulation of facilitative glucose transporters could contribute to the protective actions of the flavonoids against diabetes and Alzheimer's disease.

The pressurized hot water extraction (PHWE) of six representative compounds from black tea brick was investigated in a semi-continuous extractor under the conditions of various temperatures (120–180 °C) and water flow rates (6–18mLmin-1). The extracted solutions were dark brown liquid suspensions, and a significant proportion of the six compounds (70.7–92.0%) was found in the supernatant phase after centrifugation. Theophylline is the most stable compound with respect to increasing temperature and extraction time. Epicatechin gallate (ECG) and epigallocatechin gallate (EGCG) were sensitive to temperature, while the other compounds (caffeine, catechin, and gallocatechin gallate (GCG)) were affected by both temperature and water flow rate. The optimum conditions were found to be 160 °C and 12 mL min−1. Compared to the traditional tea brewing (TTB) method, PHWE can achieve significantly higher extraction yields of theophylline, caffeine, catechin, and GCG.

Hazelnut shells are the major byproduct of the hazelnut industry. The objectives of this study were to optimize the conditions for extracting phenolics and to identify and quantify the phenolics in hazelnut shells. Preliminary optimization showed that a high recovery of phenolics could be achieved with shell particle size less than 0.5 mm when extracted with acetone at 50 °C. Response surface experiments showed that a 10 g/l liquid to solid ratio, 58% acetone, and 12 h extraction time yielded the highest amount of phenolics. Twenty-seven phenolic compounds were identified in hazelnut shells by mass spectrometry. Coumaroylquinic acid, epicatechin gallate, quercetin, and six other phenolics were identified in hazelnut shells for the first time. The most abundant phenolics in hazelnut shells were catechin, epicatechin gallate, and gallic acid, as quantified by high performance liquid chromatography (HPLC). These results can be useful for the development of industrial extraction processes of natural antioxidants from hazelnut shells.

Phytochemical investigation of the CH2Cl2/MeOH (1:1) extract of the roots of Lannea rivae (Chiov) Sacleux (Anacardiaceae) led to the isolation of a new alkenyl cyclohexenone derivative: (4R,6S)-4,6-dihydroxy-6-((Z)-nonadec-14′-en-1-yl)cyclohex-2-en-1-one (1), and a new alkenyl cyclohexanol derivative: (2S*,4R*,5S*)-2,4,5-trihydroxy-2-((Z)-nonadec-14′-en-1-yl)cyclohexanone (2) along with four known compounds, namely epicatechin gallate, taraxerol, taraxerone and β-sitosterol; while the stem bark afforded two known compounds, daucosterol and lupeol. Similar investigation of the roots of Lannea schweinfurthii (Engl.) Engl. led to the isolation of four known compounds: 3-((E)-nonadec-16′-enyl)phenol, 1-((E)-heptadec-14′-enyl)cyclohex-4-ene-1,3-diol, catechin, and 1-((E)-pentadec-12′-enyl)cyclohex-4-ene-1,3-diol. The structures of the isolated compounds were determined by NMR spectroscopy and mass spectrometry. The absolute configuration of compound 1 was established by quantum chemical ECD calculations. In an antibacterial activity assay using the microbroth kinetic method, compound 1 showed moderate activity against Escherichia coli while compound 2 exhibited moderate activity against Staphylococcus aureus. Compound 1 also showed moderate activity against E. coli using the disc diffusion method. The roots extract of L. rivae was notably cytotoxic against both the DU-145 prostate cancer cell line and the Vero mammalian cell line (CC50 = 5.24 and 5.20 μg/mL, respectively). Compound 1 was also strongly cytotoxic against the DU-145 cell line (CC50 = 0.55 μg/mL) but showed no observable cytotoxicity (CC50 > 100 μg/mL) against the Vero cell line. The roots extract of L. rivae and L. schweinfurthii, epicatechin gallate as well as compound 1 exhibited inhibition of carageenan-induced inflammation.

The efficacy of raw and processed products of Polygonum multiflorum (PM) varies greatly. "Nine cycles of steaming and sunning" (NCSS) is recognized as an effective technology in enhancing efficacy and reducing toxicity for PM. In this paper, PM was prepared differently into three groups (including group R, M, and "9"), which represent raw PM, PM processed using the method of Chinese Pharmacopoeia (ChP) and PM processed using traditional NCSS, respectively. The purpose is to establish an effective method to distinguish raw PM from different processed products and highlight the rationality of processing technology. The main organic compounds that could distinguish these three groups of samples were identified by in-depth mining of mass spectral information and various chemometric methods. Level of related metal cations have been quantified and used as another important distinguishing markers. The electronic tongue was utilized to determine the taste traits of aqueous extract from PM. Furthermore, the material basis that caused the difference in taste was discovered according to correlation analysis. In detail, saltiness has the most important contribution associated with the concentrations of K+ and Na+, however, bitterness and astringency were mainly associated with the contents of epicatechin gallate, catechin, procyanidin B1, procyanidin B2 and epicatechin. This study proposed a novel and effective strategy for identification of processing technology of PM. It lays the foundation for clarifying the modern scientific recommendations of processing technology to PM. On the other hand, it also provides a reference for related researches on other traditional Chinese medicine (TCM).

Liupao tea is one kind of dark tea with a unique flavor that can be attributed to the microbiome. Howerver, the role of the microbiome is unknown in pile fermention of Liupao tea. Illumina MiSeq sequencing technology was used in this study to analyze microbial community composition during Liupao tea pile-fermentation. The relationship between microbial colonies and dominant chemical components was also evaluated using Pearson analysis. The result shown that contents of cafeine, gallic acid, free amino acids (Free AA), water-soluble pectins (WSP), tea polysaccharides (TPS), and water-soluble carbohydrate (WSC) all increased during fermentation while contents of epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), gallocatechin gallate (GCG), epicatechin (EC), catechins (+C), water extract (WE), tea polyphenols (TP) and flavonoids decreased. The dominant microbial community succession comprised Sphingomonas (23.68%), Methylobacterium (17.67%), Chryseobacterium (12.55), Aspergillus (16.70%), Cladosporium (8.36%), Penicillium (6.07%), and Blastobotrys (1.54%) in the early stage of fermentation, followed by Staphylococcus (59.05%), Brachybacterium (9.66%), Kocuria (9.81%), Blastobotrys (65.07%), Aspergillus (21.10%), and Rasamsonia (11.06%) at later stages. Amongst these, relative abundances of Lactobacillus in probiotics in middle and late fermentation remained relatively high. Genus of Aspergillus, Blastobotrys, Brachybacterium and Kocuria were signifcantly (P

The barks of Anacardium occidentale (cashew tree) been used for centuries in the popular pharmacopoeia of South America and West Africa for the treatment of infections and neurodegenerative diseases. Thus, this work aimed to evaluate the biological effect of the ethanolic extract of the barks against strains of Candida spp. and cancer cell lines, as well as identifying the chemical constituents present in the product. For that, the extract was submitted to an UPLC-QTOF/MS, which mass fragments were compared in the literature at the botanical family level. For antifungal activity, the serial microdilution method was used in varying concentrations, and the modifier of fluconazole in sub-inhibitory concentrations (CFM/16). Cytotoxicity was evaluated using the MTT method [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazol bromide] in five cell lines (HL-60, NCI-H292, HCT-116, P815 and L929). Eight compounds were identified, including gallic acid, luteolin, epicatechin gallate and agathisflavone. An antifungal effect of the extract was observed for the strains of Candida albicans, Candida krusei and Candida tropicalis, with IC50 lower than 400 μg/mL. In addition, there was a synergistic action with fluconazole against C. albicans and C. tropicalis. As for antitumor activity, there was a moderate activity against all cancer lines, showing low cytotoxicity for the normal line, making the extract an excellent candidate for drug development. The ethnopharmacological use of A. occidentale by populations for the treatment of DIP’s and neurodegenerative diseases, reveal that this organ has biological actions against microorganisms that cause infections, as well as being capable of causing toxicity in cancer cells.

Three sauces with macauba pulp were formulated: i) without gum (SWG); ii) with xanthan gum (SXG); and iii) with gum arabic (SAG). The sauces were stored in glass and polypropylene (PP) in a refrigerator at 5 °C. Macauba pulp has 26.19% lipids, 68.76% oleic acid, 9.03% linoleic acid and 40% dietary fibers. Flavanols such as catechin, epicatechin gallate, epigallocatechin gallate and procyanidin B2 were predominant, which contributes to the antioxidant activity. The sauces had a high fiber content (10%) and low fat content (6%), with an intense yellow color due to the carotenoid content. The sauces showed non-Newtonian behavior with stability influenced by the storage temperature. The SXG stored in PP bottles showed the highest stability (100%) for 28 days of storage at 5 °C. SGA showed lower peroxide value in PP bottles at 5 °C and was preferred by the tasters. Macauba pulp is an alternative base ingredient for formulating sauces.

Skin aging is caused by oxidative stress and the enhanced activation of proteolytic enzymes. Inhibition of these mechanisms by natural plants might be a promising approach to prevent skin aging. The flowers of Lagerstroemia speciosa and Lagerstroemia floribunda are unused parts of agricultural products. They have been reported to possess antioxidant activity and inhibitory properties against matrix metalloproteinase enzymes. In the present study, the ethanolic flowers extracts of L. speciosa and L. floribunda were studied for their total phenolic, flavonoid, and anthocyanin contents, and antioxidant properties. Additionally, the active compounds were identified using high performance liquid chromatography (HPLC). The extracts were also evaluated for their inhibitory effects against hyaluronidase, elastase and tyrosinase. Finally, the extracts were investigated for their protective effects on hydrogen peroxide-induced oxidative stress in human keratinocytes. Results showed that antioxidant activities of the flowers extracts of L. speciosa and L. floribunda were equal to that of ascorbic acid. Both plants also inhibited hyaluronidase, elastase and tyrosinase activity. In addition, these flower extracts showed remarkable inhibitory potential against hyaluronidase, which was higher than that of the standard oleanolic acid. Furthermore, these extracts were found to inhibit hydrogen peroxide-induced cell death in human keratinocytes. L. speciosa extract exhibited higher antioxidant properties, enzymatic inhibitory activities and cytoprotective effects compared with that of L. floribunda . HPLC analysis had revealed that ellagic acid, epicatechin gallate, and quercetin were the major compounds in both extracts, but with higher contents in L. speciosa than in L. floribunda . Taken together, the results suggest that these flower extracts can be considered as new natural sources to be potentially used as anti-aging ingredients in skin care formulations.

A complete characterization of the phenolic profile of leaves infusions from seven Mexican Quercus species was developed using different LC-DAD-MS/MS methodologies. The main families of phenolic compounds identified and quantified were: hydrolyzable tannins and flavonol glycosides, based on their fragmentation patterns and UV spectra, proanthocyanidins analyzed after acid-catalysis in the presence of phloroglucinol, and phenolic acids evaluated using UPLC-triple quadrupole mass spectrometer (QqQ). White oak species showed the largest amount of total phenols (830–2956 mg/L) with hydrolyzable tannins as the predominant group (60–96%), mainly vescavaloninic acid, vescalagin, and castalagin. Red species (total phenolics 129–280 mg/L), showing proanthocyanidins as the dominant family, consisted of units of catechin, gallocatechin and in less amount epicatechin gallate and epigallocatechin gallate and larger percentages of phenolic acids (10–19%).

Lipid peroxidation-derived reactive carbonyl species (RCS) such as acrolein and 4-hydroxynonenal pose health risks. We characterized the RCS-scavenging reactions of tea catechins in an aqueous solution and in baked cake. Acrolein's reaction with each of the major tea catechins (epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate) resulted in the formation of mono-, di-, and tri-acrolein conjugates of each catechin as revealed by our LC-linear ion trap MS analysis. The formation of the acrolein-conjugates of the four catechins was confirmed in the reaction of acrolein with green tea powder (matcha) extract. The addition of matcha tea powder to cake dough significantly suppressed the accumulation of RCS during cake baking. The mono-acrolein conjugates of the four major catechins were detected in the baked cake. The RCS-scavenging capability of tea catechins offers a new functionality of matcha tea powder, and its heat stability demonstrates the usefulness of matcha as a food additive.

Recently, in addition to carboxylesterases (CESs), we found that arylacetamide deacetylase (AADAC) plays an important role in the metabolism of some clinical drugs. In this study, we screened for food-related natural compounds that could specifically inhibit human AADAC, CES1, or CES2. AADAC, CES1, and CES2 activities in human liver microsomes were measured using phenacetin, fenofibrate, and procaine as specific substrates, respectively. In total, 43 natural compounds were screened for their inhibitory effects on each of these enzymes. Curcumin and quercetin showed strong inhibitory effects against all three enzymes, whereas epicatechin, epicatechin gallate (ECg), and epigallocatechin gallate (EGCg) specifically inhibited AADAC. In particular, ECg and EGCg showed strong inhibitory effects on AADAC (IC50 values: 3.0 ± 0.5 and 2.2 ± 0.2 μM, respectively). ECg and EGCg also strongly inhibited AADAC-mediated rifampicin hydrolase activity in human liver microsomes with IC50 values of 2.2 ± 1.4 and 1.7 ± 0.4 μM, respectively, whereas it weakly inhibited p-nitrophenyl acetate hydrolase activity, which is catalyzed by AADAC, CES1, and CES2. Our results indicate that ECg and EGCg are potent inhibitors of AADAC.

The quality and flavor of green tea can be affected by various factors, which are closely related to the metabolite composition of tea. In this study, 66 Xinyang Maojian tea (XYMJ) samples produced by four cultivars, grown in different elevations and manufactured by different processing methods were analyzed by untargeted ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry and chemometrics. 1912 ion features were detected and 95 metabolites were identified tentatively through a customized in-house library. Projection to latent structures discriminate analysis showed high capability to explain the cultivar variation. 54 metabolites were found to be responsible for the differentiation of the four cultivars. 27 metabolites including epigallocatechin gallate, epicatechin gallate, theanine, theogallin showed close correlation with elevation, resulting enhanced umami flavor of the high elevation tea. The differences between manual and mechanical tea were not significant. This comprehensive study is of great reference value for other types of tea.

Apart from geographical difference and processing method, the maturity of fresh tea shoot is an important factor that determines tea quality. However, the quality development and chemical variation of green tea with tea shoot maturity remain unclear. This study aimed to investigate the metabolic consequences of tea shoot maturity on the taste and aroma quality of green tea by metabolite profiling. In terms of taste quality, a concentration-dependent decrease with tea shoot age was observed in gallic acid and caffeine. The levels of catechin, epicatechin, and epigallocatechin increased with tea shoot maturity, whereas those of epicatechin gallate, epigallocatechin gallate, and total catechins decreased. Furthermore, the maximum contents of most amino acids were recorded in green tea processed from one bud with two leaves. In terms of aroma quality, volatile profiles of green tea were analyzed by gas chromatography–mass spectrometry combined with chemometrics. A total of 32 differential volatile organic compounds showing significant differences were identified and divided into Groups I and II, which contribute undesirable flavor and sweet flowery aroma to tea, respectively. The relative abundance of Group I increased with tea shoot maturity whereas that of Group II decreased. These findings can be used in guiding the production of green tea.

A simple, convenient and efficient enzyme immobilization method through phytic acid (PA) modified α-Glucosidase (α-Glu)/Cu3(PO4)2·3H2O hybrid nanoflower was developed. The structural properties of the materials were studied by several characterization techniques. Subsequently, the enzymatic reaction conditions such as the pH value and temperature were optimized, and the enzyme kinetics and inhibition parameters were determined. The PA modified α-Glu/Cu3(PO4)2·3H2O hybrid nanoflower had better enzymatic activity under a wide pH range and high temperature than the free one. After seven successive cycles, the PA modified α-Glu/Cu3(PO4)2·3H2O hybrid nanoflower could still maintain approximately 63.0 % of its initial immobilized enzyme activity. The Michaelis-Menten constant (Km) and the half-maximal inhibitory concentration (IC50) of acarbose were determined as 0.77 mM and 15.01 μM, respectively. In addition, the material was applied to evaluate the inhibitory activity of ten phenolic compounds on α-Glu, and epicatechin gallate, gallocatechin gallate, epigallocatechin gallate and rosmarinic acid showed good inhibitory activity with % of inhibition of (53.42 ± 2.39)%, (37.28 ± 1.32)%, (37.08 ± 0.63)% and (35.53 ± 0.23)%, respectively. These results indicate that the PA modified hybrid nanoflower is an efficient method of α-Glu immobilization.

This study evaluated freeze drying combined with microwave vacuum drying (FD-MVD) for functional okra snacks. FD-MVD was compared using four different drying methods: hot air drying (AD), freeze drying (FD), microwave vacuum drying (MVD), and hot air drying combined with microwave vacuum drying (AD-MVD). For main antioxidant components including epigallocatechin gallate (EGC), epicatechin gallate (EGCG), epigallocatechin (ECG), quercetin 3-O-diglucoside, and quercetin 3-O-(malonyl) and antioxidant properties (IC50, AEAC, FRAP, ABTS, TF, and TPC) and color (L*, a*, and b*), the values of FD-MVD were similar to those of FD and significantly higher than those of AD, MVD, and AD-MVD (P

Polyphenols form one of the largest groups of natural compounds and possess a wide range of biological properties. These activities can be influenced by the galloyl moiety within their structures. A multitude of galloylated polyphenolic compounds occurs in nature, but galloylated phenols are also produced synthetically to influence their biological properties. This review provides a comprehensive summary of current knowledge about natural (galloylated catechins, theaflavins and proanthocyanidins, penta-O-galloyl-β-d-glucose, gallotannins, ellagitannins, ellagic acid and flavonols) and semisynthetic gallates with a focus on their biological activity and toxicity issues. The effects of tea catechins (epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate) and semisynthetic galloyl esters of the flavonolignans silybin and 2,3-dehydrosilybin from the milk thistle (Silybum marianum) on angiogenesis were used as examples of the structure-activity relationship (SAR) study.

Ultrasound is considered as a potential novel technique for improving the quality of some wines. In this paper, a model wine firstly was constructed with the standards of ( )-epicatechin gallate (ECG) and bovine serum albumin (BSA) as target compounds. Then, the experiments were conducted to investigate the effect of ultrasonic irradiation on the binding properties between ECG and BSA including quenching mechanism, binding parameters, binding forces, energy transfer distance and conformational changes determined by spectral analysis. The results indicate that ultrasound definitely has some regular effects on the binding interaction of BSA and ECG, and can induced the conformation variation of BSA in the simulated wine, which may suggest that the ultrasound might be employed to modify the wine organoleptic property by regulating the interaction between phenolic compounds and proteins from the autolysis of yeasts, since they are similar to the standards of ECG and BSA, respectively.

Thymus schimperi is a highly localized and a rare plant endemic to Ethiopia. An optimized and validated high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC–ESI–MS/MS) method was applied to characterize 23 polyphenolic compounds found in ethyl acetate extracts of the plant. From those, flavones dominated and luteolin was the major component contributing 21.83% of the total composition (or 46.05 ± 0.59 g/kg of fresh sample weight). Validation data showed a determination coefficient (R2) ≥ 0.997. Limits of detection (LOD) and quantification (LOQ) were 0.03–0.97 and 0.11–3.23 mg/L, while recovery values spiked at 5 and 50 mg/L were between 70.89–115.39 and 67.65–120.19%, respectively. Except for caffeic acid and epicatechin gallate, the relative standard deviations (%RSDs) were far below 15%, showing acceptable precision values. The plant extracts inhibited cell proliferation and induced cell death in human gastric adenocarcinoma (AGS) and liver hepatocellular carcinoma (HepG2) cancer cells. This is the first report of polyphenolic components from T. schimperi being characterized using HPLC–ESI–MS/MS. Being components of many edible vegetables, fruits, and spices, the identified polyphenols suggest that T. schimperi could be a potential food with promising health benefits.

Toxins are natural or chemical poisonous substances with severe side effects on health. Humans are generally exposed by widespread toxic contaminations via air, soil, water, food, fruits and vegetables. Determining a critical antidote agent with extensive effects on different toxins is an ultimate goal for all toxicologists. Traditional medicine is currently perceived as a safe and natural approach against toxins. In this regard, we focused on the protective effects of green tea (Camellia sinensis) and its main components such as catechin, epicatechin, epicatechin gallate, gallocatechin, epigallocatechin and epigallocatechin gallate as a principal source of antioxidants against both natural and chemical toxins. This literate review demonstrates that protective effects of green tea and its constituents were mainly attributed to their anti-oxidative, radical scavenging, chelating, anti-apoptotic properties and modulating inflammatory responses. Although, some studies reveal they have protective effects by increasing toxin metabolism and neutralizing PLA2, proteases, hyaluronidase and l-amino acid oxidase enzymes.

The effects of epigallocatechin gallate (EGCG), epigallocatechin (EGC) and epicatechin gallate (ECG) on the chemical and cell-based antioxidant activity, sensory properties, and cytotoxicity of a catechin-free model beverage were modeled using response surface methodology. Results showed that ECG presented the highest reducing capacity while EGCG presented the highest Cu2+ chelating ability. Binary interactions (EGCG/EGC and EGCG/ECG) had an additive effect on CUPRAC, DPPH and Cu2+ chelating ability. The mixture containing 67.4% ECG and 32.6% EGCG was the optimal combination of flavanols (OPC). In a beverage model - chrysanthemum tea - OPC enhanced the anti-proliferative activity in relation to OVCAR-3, HEK293 and HFL1 cells and decreased the intracellular generation of reactive oxygen species. OPC enhanced the bitterness and astringency of the beverage models impacting in a decrease in overall acceptance. The pasteurization process did not decrease the antioxidant activity and the flavanol concentration of the beverages.

In this study, kinetics of binding between α-amylase and green tea flavonoids were investigated by fluorescence quenching (FQ). Their effect on α-amylase inhibition was evaluated. Whereas epicatechin (EC) and epigallocatechin (EGC) exhibited slow binding kinetics (in the order of minutes), epicatechin gallate (ECG) and epigallocatechin gallate (ECGC) exhibited very rapid binding (in the order of seconds) with Human Salivary α-amylase (HSA) and Porcine Pancreatic α-amylase (PPA). EGCG reached maximum inhibition of HSA and PPA with short incubation time whereas maximum inhibition of HSA and PPA by EC was reached only after 45 to 60 min of incubation. Similar results with ECG and EGC, but not in line with FQ kinetics, highlighted possible interferences of starch-flavonoid interaction in the binding and inhibition process. These results suggest that incubation times of enzymes and flavonoids shall be evaluated prior to enzyme inhibition testing in order to ensure consistent and reliable results.

Epicatechin gallate (EG), which is isolated from green tea, has been investigated as a corrosion inhibitor for metallic materials such as bronze in a corrosive solution of 3% NaCl using electrochemical techniques such as electrochemical impedance spectroscopy, polarization curves, and scanning electron microscopy. The results showed that 10 ppm of epicatechin gallate is the best concentration to protect the metallic surface of bronze. The measurements with different immersion times showed that the epicatechin gallate is stable for 28 days, while the adsorption of this compound was found to follow the Langmuir isotherm by a mixed process of physisorption-chemisorption. It was proven by SEM-EDS that the presence of the inhibitor film diminishes the corrosion process. Quantum mechanical calculations showed that the mixed-type adsorption can be rationalized by means of electrostatic interactions between EG and the bronze surface, within physisorption regime, and by covalent bonding, corresponding with chemisorption, through oxygen atoms. Reactivity indices shown that EG molecules provides the bronze surface with a cover almost inert against nucleophilic and electrophilic attacks.

Tea polyphenols have become one of the promising healthcare molecules due to their anti-cancer, anti-oxidant, and anti-obesity capacities, making tea among the most popular and functional beverages worldwide. However, the sensitive and simple detection and discrimination of tea polyphenols is difficult to achieve since the analogues usually have similar chemical structures with polyhydroxy. Herein, a self-assembly system based on a cationic perylene diimide molecule tagging with phenylboric acid group (PDI-PBA) was constructed for detection and discrimination of catechin molecules (Epicatechin, Epicatechin gallate, Epigallocatechin, Epigallocatechin gallate), a subgroup of tea polyphenols. PDI-PBA could recognize tea polyphenols by dynamic borate ester bonds between PBA groups on PDI-PBA and cis-diols on tea polyphenols. Moreover, the fluorescence quench ratios of PDI-PBA were determined by the different aggregation degrees induced by every tea polyphenol with the unique chemical structure, especially cis-diol numbers. Thus, the selective discrimination could be easily realized by linear discriminant analysis (LDA). The developed system relies mainly on dynamic borate ester bonds between the probe and substrates, the self-assembly of PDI-PBA, and polyhydroxy characteristic of tea polyphenols. This work provides a new strategy for sensitive detection and discrimination of tea polyphenols.

Vascular smooth muscle cells (VSMCs) lesions play an important role in atherosclerosis. The latest findings indicate that green tea extract has potential benefits for patients with atherosclerosis, but the components and mechanisms of action are unknown. (−)-Epicatechin gallate (ECG) is the main active ingredient extracted from green tea and has significant biological functions. However, the mechanism of ECG in atherosclerosis remains unclear. Therefore, we investigated the intervention of ECG on VSMCs induced by oxidized low-density lipoprotein (ox-LDL). The results show that ECG reduces the inflammatory response by preventing the overproduction of inflammatory mediators in VSMCs. ECG regulates the cell cycle and down-regulates the expression of proliferating cell nuclear antigen (PCNA) and cyclinD1, and then exerts an anti-proliferative effect. Furthermore, inhibition of the expression of matrix metalloproteinase 2 (MMP-2) and intercellular adhesion molecule 1 (ICAM-1) may be the mechanism by which ECG inhibits the migration of ox-LDL-induced VSMCs. Oil red O staining results show that ECG can improve cell foaming and reduce the content of total cholesterol (TC). In addition, ECG significantly reduces reactive oxygen species activity and also reduces the expression of p-p38, p-JNK, p-ERK1/2, p-IκBα, p–NF–κBp65, and TLR4. These results indicate that ECG has potential clinical applications for preventing atherosclerosis.

An orthogonal L1643 × 22 test design was applied to select the optimum conditions for extracting flavan-3-ols in grape seeds. Highest yield of flavan-3-ols was achieved with 80% methanol, a ratio [1:30 (g/mL)] of sample-to-solvent, sonication for 20 min, and extraction at 25 °C for 12 h in darkness. The optimized analytical method for HPLC separation was a multistep gradient elution using 1% formic acid (A) and acetonitrile containing 1% formic acid (B), at a flow rate of 0.6 mL/min in 36 min. Moreover, fourteen flavan-3-ols were separated and identified using HPLC-ESI-MS/MS, including four monomers ((+)-catechin, (-)-epicatechin, epigallocatechin gallate and epicatechin gallate) and ten oligomers (three dimers, four trimers, two tetramers and one pentamer). The optimized method was used to determine flavan-3-ols content and compositions among ten representative cultivars. The new wine grape – Beihong, had higher flavan-3-ols content and polymerization than classic wine grapes – Cabernet Sauvignon, Merlot, Semillon and Riesling.

Introduction Skin aging is a multifactorial process caused by chronological changes and environmental factors. Green tea, a processed tea plant (Camellia sinensis (L) Kuntze), possesses health benefits and has been used in traditional medicines and natural products. However, the anti-skin aging effect of green tea in clinical trials has been a controversial issue. To clarify this without the interference of systemic involvement, the objectives of study were to investigate the activities of green tea against skin aging in B16F10 melanoma cells and human skin fibroblasts. Methods Green tea leaves were extracted to standardise the phenolic profile. The cytotoxicity and the anti-skin aging activities, including melanogenesis assay, antioxidant activity, collagen content analysis, and matrix metalloproteinase-2 inhibitory assay, were evaluated in cell culture. Results Green tea in this study composed mainly of epigallocatechin gallate (1,903.77 ± 33.59 μg/mL), epigallocatechin (930.24 ± 27.04 μg/mL), and epicatechin gallate (607.84 ± 22.65 μg/mL). The cell viabilities of 0.5 % (0.0875 mg/mL) green tea, the noncytotoxic concentration, were 96.04 ± 6.76 and 93.44 ± 0.95 % in B16F10 melanoma cells and human skin fibroblasts, respectively. Green tea exhibited the activities against skin aging, including the significant suppression of melanin production via inhibition of tyrosinase and tyrosinase-related protein-2 activities, the potent antioxidant, and the significant matrix metalloproteinase-2 inhibition (p Conclusions The study results have shown that green tea may be a functional processed plant which could be used as an anti-skin aging agent in natural remedies, including food, health, and cosmetic products.

This study aimed at investigating phenolic composition, anti-quorum sensing and enzyme inhibitory potential of Camellia sinensis and Curcuma longa. HPLC-DAD identified and quantified curcumin (398.67 ± 0.34 mg/g), demethoxycurcumin (261.39 ± 0.27 mg/g) and bisdemethoxycurcumin (173.32 ± 0.46 mg/g) in C. longa extract and eight phenolics in C. sinensis with major components epigallocatechin (365.53 ± 0.49 mg/g), epicatechin (324.05 ± 0.37 mg/g) and epicatechin gallate (94.48 ± 0.27 mg/g). Seven pathogenic microorganisms (Escherichia coli, Listeria monocytogenes, Enterococcus faecalis, Salmonella typhi, Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa) were subjected to antimicrobial and antibiofilm assays and lowest MIC values were 0.3125 mg/mL exhibited by Camellia sinensis on S. aureus and Curcuma longa on P. aeruginosa. At MIC and sub-MIC concentrations, extracts displayed excellent antibiofilm activities especially at MIC concentrations and S. aureus was most susceptible to extracts of C. sinensis (80.56 ± 1.16%) and C. longa (75.79 ± 0.58%). Extracts exhibited concentration-dependent percentage inhibitions of motility and violacein production but only C. longa displayed good antiquorum sensing activity at MIC (18.6 ± 3.0 mm) and MIC/2 (14.5 ± 0.2 mm). C. longa extract disrupted signal reception by CV026 of externally supplied acyl homoserine lactone within revealed anti-quorum sensing zones. Extracts displayed moderate anticholinesterase, anti-urease and anti-tyrosinase activities. Both food extracts can control foodborne infections.

The Eugenia calycina Cambess, also known as pitanga-do-cerrado, is an unexplored Brazilian fruit used by native people for the treatment of diabetes. The aim of this study was to identify the phenolic compounds from the leaves, pulp and seed of Eugenia calycina by using LC-MS-based targeted and untargeted analysis. The LC-MS-based targeted quantitative analysis showed a high phenolic content in all plant parts in which the ellagic acid was the main phenolic compound with values of 8244.53 µg/g dw (leaves), 5054.43 µg/g dw (pulp) and 715.42 µg/g dw (seed). The leaves, pulp and seed showed a high total phenolic content of 20371.96, 7139.70 and 2204.75 µg/g dw, respectively. In addition, the LC-MS-based targeted analysis showed ellagic acid, myricitrin and epicatechin gallate as the main phenolic compounds in the Eugenia calycina. The LC-MS-based untargeted analysis showed the phytochemical profile of the leaves, pulp and seed in which 153 phytochemicals from different chemical classes were annotated, including organic acids, phenolic acids, flavonoids, and other compounds. The Eugenia calycina has high potential as a plant-based food due to its phytochemical profile and high phenolic content.

In this work, α-glucosidase was immobilized on a type of nanoscaled magnetic materials Fe3O4@ZIF-67 to construct a biomicroreactor for rapid screening α-glucosidase inhibitors. The parameters that affected the immobilization efficiency were investigated. Under optimal conditions, the amount of α-glucosidase loaded was up to 79.07 μg·mg−1. Then, the enzyme biomicroreactor was immobilized by an external magnetic field in a tube connecting HPLC and micro-injection pump at both ends to form a magnetic online screening system. The screening flow rate and eluent organic solvent ratio during the screening process were optimized. XinYang MaoJian crude tea extract was tested to verify this online screening method, and three inhibitors (catechin, epigallocatechin gallate and epicatechin gallate) were fished by this magnetic online screening system. Based on the classical pNPG method, the inhibitory activities on α-glucosidase were further verified and studied. Compared with the traditional ligand fishing methods, the screening method established in this work can integrate screening, elution and analysis. It can simply, efficiently and directly screen and identify potential α-glucosidase inhibitors from natural sources. This method was expected to provide an effective basis for accelerating the development of new hypoglycemic drugs.

Background Lipid oxidation is responsible for the deterioration of the nutritional and organoleptic qualities of foods. It also leads to the formation in these products of compounds which are harmful for the consumer's health. The synthetic antioxidants used by industries in order to solve this problem are also prone to be toxic and quite volatile at high temperatures. On the other hand, the trend among researchers to replace the synthetic antioxidants with natural ones is increasing because of their potential health benefits. In this study, old Cameroonian green tea leaf methanolic extracts were added in palm olein and its efficiency in delaying the oxidation of oil under forced storage conditions was assessed. Methods The plant material was extracted with methanol and its total phenolics content evaluated by colorimetry, followed by the qualitative identification of some phenolic antioxidants by HPLC-DAD and ESI-MS. After preliminary antioxidant studies, the extract was added in oil at concentrations that ranged from 200 to 1800 ppm. Oil containing butylated hydroxytoluene (BHT) and oil without antioxidant served as positive and negative controls, respectively. The oxidative stability of these oil samples was evaluated by determining their oxidation induction times on Rancimat (at 110 °C) and measuring their oxidative state by the Schaal oven test method during 30 days of storage at 70 °C. Here, oil samples were collected every 10 days and their peroxide, p -anisidine, total oxidation, thiobarbituric acid, iodine values as well as changes in their linoleic acid profile gas chromatography coupled to flame ionization detector (GC/FID) were evaluated. Results The outcomes showed the total phenolics content of the extract to be 53.5 mg GAE/g. Gallic acid, epicatechin gallate, gallocatechin and epigallocatechin gallate were the phenolic antioxidants detected. The induction times of palm olein supplemented with the extract (200–1800 ppm) were found to be in the range of 24.8–28.9 h, while those of control and oil containing BHT were 20.1 and 22.7 h, respectively. The extracts, at all concentrations, were also found to be efficient like butylated hydroxytoluene in inhibiting the oxidation of palm olein during 30 days of storage at 70 °C. Conclusion The investigations showed that old Cameroonian green tea leaves are a viable source of natural antioxidants for delaying palm olein oxidation.

Shaking the tea leaves is the key manipulation to making oolong tea. It contributes to the formation of flavor and fragrance in oolong tea. The dynamic variations of catechins and volatile organic compounds (VOCs) during the shaking process were investigated. The results showed that the contents of epicatechin, epigallocatechin, epicatechin gallate (ECG), and epigallocatechin gallate (EGCG) first decreased after the shaking and then increased to the initial value before the next shaking. Geraniol, linalool and its oxides, and phenylethyl alcohol showed similar variations. The contents of trans-β-ocimene, 1H-indole, and 3-hexenyl hexanoate increased after the second or third shaking (the late fermentation stage). However, the contents of aldehydes showed an opposite trend to other VOCs. The abundance of phenylethyl alcohol was positively related to the content of ECG and EGCG ​during fermentation, whereas the abundance of cis-3-hexenal was negatively related to the content of ECG. The correlations between catechin and VOCs indicated that shaking affected the chemical transformation of the compounds in oolong tea.

Tea, one of the most consumed beverages in the world, has several health benefits which include antioxidant and reducing the risk of diabetes, heart-attack and cancer etc. Polyphenols such as catechin, epicatechin, epicatechin gallate, epigallocatachin and epigallocatechin gallate (EGCG), which generally contain combination of 1,2-dihydroxy benzene (1,2-DHB), 1,3-dihydroxy benzene (1,2-DHB) and 1,2,4-trihydroxy benzene (1,2,3-THB) functional groups are rich in green tea. Among the various polyphenols, EGCG (1,2,3-trihydroxybenzene functional group), is viewed as the most active component for the health benefits and hence it has been assayed in the tea quality assessment. Here in, we report a simple, rapid and separation-less electro-analytical technique based on a flow injection analysis coupled dual electrochemical detector system, in which graphitized mesoporous/Chitosan modified glassy carbon electrodes (GCE/Chit@GMC) set at two different applied potentials ( E app ), 0.1 (case-I) and 0.7 V vs Ag/AgCl (case-II), controlled by a bipotentiostat, with pH 7.0 phosphate buffer as a carrier solution has been reported for the selective and simultaneous detection of 1,2,3-THB and {1,2,3-THB + 1,2-DHB + 1,3-DHB} contents in tea samples.

Antiviral effect of 10 flavonoids against feline calicivirus (FCV) and murine norovirus (MNV) was investigated on Crandell-Reese feline kidney (CRFK) cells and RAW 264.7 cells. Each cells infected with FCV or MNV was treated with different flavonoids at concentrations between 50 and 300 μM. A 200 μM dose of kaempferol and daidzein significantly reduced the FCV titer by 69.76 ± 8.71 and 63.47 ± 9.82%, respectively. A 300 μM dose of quercetin and fisetin reduced the titer of FCV titer by 56.70 ± 11.39 and 41.84 ± 11.35%, respectively. The titer of MNV was reduced by 50.47 ± 6.91 and 51.21 ± 13.38% by a 50 μM dose of fisetin or a 150 μM dose of epicatechin gallate, respectively. A 50 μM dose of daidzein and 100 μM of quercetin reduced the MNV titer by 46.32 ± 8.70 and 45.78 ± 9.81%, respectively. The pre-treatment of quercetin, fisetin, daidzein, and epicatechin gallate demonstrated the anti-noroviral activity against MNV and FCV.

The aim of this study was to model the extraction of phenolic antioxidants and identify the principal individual phenolic compounds of white tea by LC-DAD-MS/MS. A Box-Behnken design was applied to evaluate the effects of time, temperature and ethanol concentration in the extraction of phenolics and in vitro antioxidant activity. All mathematical models proposed by multiple regression analysis were significant (P 0.80). A simultaneous optimization was performed using DPPH, ABTS, FRAP, (−)-epigallocatechin gallate, and (−)-epicatechin gallate to maximize the phenolic extraction and suggested optimum conditions of 10 min, 66 °C and 30% ethanol solution, with absolute error lower than 7%. The suggested optimum conditions were confirmed by external validation. The principal individual compounds identified by mass spectrometry were gallic acid, 5-galloylquinic acid, caffeine, theobromine, gallocatechin, epigallocatechin, epicatechin, epigallocatechin gallate, and epicatechin gallate.

This study is focused on optimizing, by surface response methodology, the mixture of natural additives: nisin (an antimicrobial peptide) in combination with avocado seed or avocado peel extracts (both with antioxidant capacities) in order to maximize the antioxidant activity and antimicrobial response against some food-borne bacteria such as Listeria . The peel or seed extracts used in the mixture showed radical scavenging capacity and antioxidant activity due to their polyphenol composition, including kaempferide, epicatechin, chlorogenic acid, epicatechin gallate, among others. During optimization, the results showed that the major antioxidant response in the mixture was mainly provided by the peel extract compared with nisin, seed and their combinations in different proportions. In the antimicrobial response, a synergic effect was observed in the mixtures of each avocado byproduct extract with nisin. Maximum antioxidant and antimicrobial response were obtained with the mixture of 61% of peel extract with 39% of nisin ( p

Tea (Camellia sinensis) is rich in flavan-3-ols (catechins), especially epicatechin (EC), which is the predominant extension unit of polymeric proanthocyanidins (PAs). However, studies assessing EC’s stereochemistry are scarce. Here, a high performance liquid chromatography column using amylose tris-(3, 5-dimethylphenylcarbamate) immobilized on silica-gel as chiral stationary phases (CSPs) was applied to explore its stereochemistry and biosynthetic pathway in tea plants. The results revealed (−)-epicatechin [(−)-EC] was the predominant di-hyroxy-non-galloylated-catechins, while (+)-epicatechin [(+)-EC] was not detected. Interestingly, (−)-EC was the only product obtained from cyanidin using the partially purified native C. sinensis anthocyanidin reductase (CsANR) in the presence of reduction nicotinamide adenine dinucleotide phosphate (NADPH); meanwhile, (+)-EC was the main product using recombinant CsANR in the same conditions. In addition, (−)-EC could be obtained from (+)-catechin [(+)-C] using recombinant CsANR, which displayed C3-epimerase activity in the presence of oxidation nicotinamide adenine dinucleotide phosphate (NADP+). But the partially purified native CsANR did not possess this function. Finally, (−)-EC could result from the de-gallate acid reaction of epicatechin gallate (ECG) catalyzed by a novel partially purified native galloylated catechins hydrolase (GCH) from tea leaves. In summary, (−)-EC is likely the product of native protein from the tea plants, and (+)-EC is only produced in a reaction catalyzed by recombinant CsANR in vitro.

Poor absorption and bioavailability of procyanidins from the upper gastrointestinal tract result in the majority of the dose reaching the colon. During colonic transit, progressive microbial metabolism likely produces gradients of procyanidins and microbial metabolites along the length of the colon, suggesting that proximal and distal regions are exposed to different profiles of procyanidins and metabolites. However, previous studies have largely treated the colon as a single organ or looked at fecal profiles, and differences in the profiles of native and metabolite compounds between regions have not been observed. The metabolism kinetics of procyanidins larger than trimers and formation of metabolites in the colon have not been well characterized. Therefore, the objective of this study was to determine the kinetics of delivery and microbial metabolism of monomeric, dimeric and oligomeric procyanidins in the cecum and proximal, mid and distal colon. Sprague–Dawley rats were gavaged grape seed extract and sacrificed over 18h. Analysis of luminal contents showed distinct native and metabolite profiles for each region. Procyanidins had maximum concentrations at approximately 3h postgavage for all sections. Metabolites reached maximum concentrations from 3 to 18h postgavage. The appearance of metabolites was highly dependent on species: larger metabolites were found at earlier times in the more proximal segments, and smaller metabolites were found at later times in more distal regions. This study allowed for the observation of regions in the lower gastrointestinal tract, giving insight into the distribution and delivery of procyanidins and their microbial metabolites throughout the colon.

The present study was focused on the isolation and screening of potential tannase producing gut microbes from dung beetle Onthophagus babirussa IMBL, further optimized and characterized for industrial applications. Serratia marcescens strain IMBL5 was found to be the most potent tannase producer out of 36 isolates. The adjusted process parameters for maximum tannase yield were pH 4.5 at 45 °C and 96 h incubation. The tannase production was increased 4.46 fold i.e. 120.13 U/mL, by varying the concentration of media components using Response surface methodology. The molecular weight of purified tannase was resolved at ~40 kDa through SDS-PAGE analysis. Several functional groups including carboxyl, hydroxyl and amide groups were detected in FT-IR analysis whilst the occurrence of epicatechin gallate peaks detected from HPLC chromatogram signifying the tannin degradation. Tannase also potentially induce the antioxidant properties of green tea extract which was determined through in-vitro analysis. There was no hemolytic activity exhibited in hemolysis assay using human red blood cells which corroborated that tannase derived from S. marcescens strain IMBL5 might be a safe and promising agent in food industry.

The most important thing to do with hexavalent chromium (Cr(VI)) removal in wastewater through adsorption-reduction method is to find an adsorbent that has both strong adsorbability and reducibility. Herein, an eco-friendly material ZIF-8-EGCG, which was a combination of epicatechin gallate (EGCG) and ZIF-8, was synthesized to treat Cr(VI)-containing wastewater. At room temperature, the maximum adsorption amount of Cr(VI) reached 136.96 mg·g−1, and the Cr(VI) reduction rate (96%) was much better than that of the original ZIF-8 (37%). Such outcome was among the best in the existing studies using MOFs to treat Cr(VI). In addition, the characterization results showed that the surface of ZIF-8-EGCG was electronegative. The material was irregular sphere with pore size of 7.12 nm and BET surface area of 113.02 m2·g−1. The well-fitted Langmuir adsorption isotherm and pseudo first/second-order kinetics model suggested that the adsorption of Cr(VI) on ZIF-8-EGCG was governed by both physical and chemical processes. Stability results revealed that the overall stability of ZIF-8-EGCG due to the etched structure was slightly inferior to ZIF-8, especially at higher temperatures (>35 °C). Simultaneously, the reaction between ZIF-8-EGCG and Cr(VI) was a spontaneous, exothermic, entropic decrease process.

A simple, rapid and low-cost analytical method was employed for simultaneous determination of bioactive constituents and antioxidant capability of green tea. The strategy was based on swarm intelligence algorithms with partial least squares (PLS) such as simulated annealing PLS (SA-PLS), ant colony optimization PLS (ACO-PLS), genetic algorithm PLS (GA-PLS), and synergy interval PLS (Si-PLS) coupled with Near-infrared (NIR) spectroscopy. These algorithms were independently applied to select informative spectral variables and improve the prediction of green tea components. Results showed that NIR combined with SA-PLS and Si-PLS had a strong correlation coefficient with the wet-chemical methods for predicting epigallocatechin gallate (Rp2 = 0.97); epigallocatechin (Rp2 = 0.97); epicatechin gallate (Rp2 = 0.96); epicatechin (Rp2 = 0.91); catechin (Rp2 = 0.98); caffeine (Rp2 = 0.96); theanine (Rp2 = 0.93); and antioxidant capability (Rp2 = 0.80) in green tea. Our results revealed the potential utilization of NIR spectroscopy coupled with SA-PLS and Si-PLS algorithms as an effective and robust technique to simultaneously predict active constituents and antioxidant capability of green tea.

Catechin polyphenols and caffeine play an important role in tea quality. This study analyzed the visible and near-infrared (Vis-NIR) spectral variation and concentration differences of catechin and caffeine of fresh tea leaves (Camellia sinensis L.) in three varieties and six leaf positions, and a universal spectral model for quickly and accurately measurement of the catechin and caffeine content in the various varieties and leaf positions was established. It was found that all the catechins and caffeine were significantly influenced by variety and leaf position. While, the Vis/NIR spectrum as an indication of internal biochemical substances was successfully used to distinguish different varieties and leaf positions with the discrimination accuracy rates of 98.15% and 100%, respectively. The quantitative relationship between the chemical components and the data obtained by Vis-NIR spectroscopy was established based on multivariate regression analysis such as partial least squares (PLS) and multiple linear regression (MLR). Furthermore, competitive adaptive reweighted sampling (CARS) and successive projections algorithm (SPA) were used to select the characteristic wavelengths for the development of simple models. Results showed that the quantitative determination models obtained good performance with the determination coefficients (R2) of 0.949, 0.893, 0.968, 0.931 and 0.917 for epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC), epicatechin (EC) and caffeine (CAF), respectively. Such high detection accuracy shows that the spectral detection model has a strong applicability for both varieties and leaf positions. The overall results of the study revealed the potential use of Vis-NIR spectroscopy as a rapid, simple and non-destructive method for the determination of four main catechins and caffeine in fresh tea leaves, and it will play a great role in the real-time detection of tea physiological information in tea garden.