•Reaction products of tea catechins with acrolein were analyzed.•One molecule of tea catechins trapped up to three acrolein molecules.•The mono-acrolein-epigallocatechin gallate conjugate structure ...was determined.•Green tea powder suppressed the formation of toxic aldehydes during cake baking.•Aldehyde-detoxifying ability of green tea powder is a practical food functionality.
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.
•A nondestructive methodology was used to study the distribution of tea metabolites.•A Teflon imprint method was suitable for tea leaf metabolite analysis using DESI-MSI.•Catechin distributions on ...both sides of tea leaf were not significantly different.•Different catechins showed different distributions within the tea leaf.•L-Theanine and valinol were distributed around the outer root cross-section.
Although specialized metabolite distributions in different tea (Camellia sinensis) tissues has been studied extensively, little is known about their within-tissue distribution owing to the lack of nondestructive methodology. In this study, desorption electrospray ionization imaging mass spectrometry was used to investigate the within-tissue spatial distributions of specialized metabolites in tea. To overcome the negative effects of the large amount of wax on tea leaves, several sample preparation methods were compared, with a Teflon-imprint method established for tea leaves. Polyphenols are characteristic metabolites in tea leaves. Epicatechin gallate/catechin gallate, epigallocatechin gallate/gallocatechin gallate, and gallic acid were evenly distributed on both sides of the leaves, while epicatechin/catechin, epigallocatechin/gallocatechin, and assamicain A were distributed near the leaf vein. L-Theanine was mainly accumulated in tea roots. L-Theanine and valinol were distributed around the outer root cross-section. The results will advance our understanding of the precise localizations and in-vivo biosyntheses of specialized metabolites in tea.
Cancer is defined as the abnormal cell growth that can cause life-threatening malignancies with high financial costs for patients as well as the health care system. Natural polyphenols have long been ...used for the prevention and treatment of several disorders due to their antioxidant, anti-inflammatory, cytotoxic, antineoplastic, and immunomodulatory effects discussed in the literature; thus, these phytochemicals are potentially able to act as chemopreventive and chemotherapeutic agents in different types of cancer. One of the problems regarding the use of polyphenolic compounds is their low bioavailability. Different types of formulations have been designed for the improvement of bioavailability of these compounds, nanonization being one of the most notable approaches among them. This study aimed to review current data on the nanoformulations of natural polyphenols as chemopreventive and chemotherapeutic agents and to discuss their molecular anticancer mechanisms of action. Nanoformulations of natural polyphenols as bioactive agents, including resveratrol, curcumin, quercetin, epigallocatechin-3-gallate, chrysin, baicalein, luteolin, honokiol, silibinin, and coumarin derivatives, in a dose-dependent manner, result in better efficacy for the prevention and treatment of cancer. The impact of nanoformulation methods for these natural agents on tumor cells has gained wider attention due to improvement in targeted therapy and bioavailability, as well as enhancement of stability. Today, several nanoformulations are designed for delivery of polyphenolic compounds, including nanosuspensions, solid lipid nanoparticles, liposomes, gold nanoparticles, and polymeric nanoparticles, which have resulted in better antineoplastic activity, higher intracellular concentration of polyphenols, slow and sustained release of the drugs, and improvement of proapoptotic activity against tumor cells. To conclude, natural polyphenols demonstrate remarkable anticancer potential in pharmacotherapy; however, the obstacles in terms of their bioavailability in and toxicity to normal cells, as well as targeted drug delivery to malignant cells, can be overcome using nanoformulation-based technologies, which optimize the bioefficacy of these natural drugs.
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•Shade treatment reduced the contents of most catechins in preharvest tea leaves.•Shade treatment increased the theaflavin contents in preharvest tea leaves.•Shade treatment increased ...polyphenoloxidase (PPO) activity in preharvest tea leaves.•CsPPO3 was highly expressed under shade treatment.•CsPPO3 recombinant protein exhibited PPO function.
Catechins and theaflavins are important metabolites contributing to tea function and quality. Catechins are known to transform into theaflavins during the tea manufacturing process, but the same transformation in preharvest tea leaves is unknown. Herein, we determined that shade treatment (dark), an agronomic practise widely used in tea cultivation, reduced the contents of most catechins, but increased the theaflavin contents, in preharvest tea leaves (cv. Yinghong No.9). This was attributed to the activation of polyphenoloxidase (PPO) activity in darkness. Furthermore, CsPPO3 was highly expressed under darkness, and thus CsPPO3 had been cloned, sequenced, and characterization. The CsPPO3 recombinant protein exhibited PPO function. Furthermore, shade treatment also reduced the catechin contents and increased the theaflavin contents in Yabukita and Hoshinomidori, suggesting that this phenomenon might not be specific to certain tea cultivars. This information will aid in understanding of theaflavin formation and its response to environmental factors at the preharvest tea stage.
Abstract
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 (ΔGbind) 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 ΔEvdW 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.
Graphical Abstract
Graphical Abstract
The use of Catechin as an antibacterial agent is becoming ever-more common, whereas unstable and easy oxidation, have limited its application. A simple and low-energy-consuming approach to synthesize ...highly stable and dispersive Catechin-Cu nanoparticles(NPs) has been developed, in which the stability and dispersivity of the NPs are varied greatly with the pH value and temperature of the reaction. The results demonstrate that the optimal reaction conditions are pH 11 at room temperature. As-synthesized NPs display excellent antimicrobial activity, the survival rates of bacterial cells exposed to the NPs were evaluated using live/dead Bacterial Viability Kit. The results showed that NPs at the concentration of 10 ppm and 20 ppm provided rapid and effective killing of up to 90% and 85% of S. aureus and E. coli within 3 h, respectively. After treatment with 20 ppm and 40 ppm NPs, the bacteria are killed completely. Furthermore, on the basis of assessing the antibacterial effects by SEM, TEM, and AFM, it was found the cell membrane damage of the bacteria caused by direct contact of the bacteria with the NPs was the effective mechanism in the bacterial inactivation.
Extensive epidemiological and clinical evidence associates diets high in flavanol-containing foods with cardiovascular health benefits in humans. Catechin and epicatechin, the most common flavanols ...in foods, are present in the diet in different enantiomeric forms. This study investigated the influence of the stereochemical configuration of flavanols on their absorption, metabolism, and biological activity. Healthy adult males were asked to consume equal amounts of the stereochemically pure flavanols (−)epicatechin, (−)catechin, (+)catechin, and (+)epicatechin (1.5
mg/kg bw) in a well-defined cocoa-based, dairy-containing drink matrix, and flavanol levels were subsequently determined in plasma and 24-h urine. The results obtained show that the stereochemical configuration of flavanols has a profound influence on their uptake and metabolism in humans. In addition, we assessed the vasodilatory activity of each flavanol stereoisomer in vivo and found (−)-epicatechin to be the single stereoisomer capable of mediating a significant arterial dilation response. Importantly, this effect was independent of the classic antioxidant properties of flavanols. Overall, these results indicate that the proposed beneficial health effects associated with the consumption of flavanol-containing foods will significantly depend on the stereochemical configuration of the flavanols ingested.
Chemotherapy for cancer treatment has been demonstrated to cause some side effects on healthy tissues and multidrug resistance of the tumor cells, which greatly limits therapeutic efficacy. To ...address these limitations and achieve better therapeutic efficacy, combination therapy based on nanoparticle platforms provides a promising approach through delivering different agents simultaneously to the same destination with synergistic effect. In this study, a novel green tea catechin-based polyion complex (PIC) micelle loaded with doxorubicin (DOX) and (-)-Epigallocatechin-3-O-gallate (EGCG) was constructed through electrostatic interaction and phenylboronic acid-catechol interaction between poly(ethylene glycol)-block-poly(lysine-co-lysine-phenylboronic acid) (PEG-PLys/PBA) and EGCG. DOX was co-loaded in the PIC micelles through π-π stacking interaction with EGCG. The phenylboronic acid-catechol interaction endowed the PIC micelles with high stability under physiological condition. Moreover, acid cleavability of phenylboronic acid-catechol interaction in the micelle core has significant benefits for delivering EGCG and DOX to same destination with synergistic effects. In addition, benefiting from the oxygen free radicals scavenging activity of EGCG, combination therapy with EGCG and DOX in the micelle core could protect the cardiomyocytes from DOX-mediated cardiotoxicity according to the histopathologic analysis of hearts. Attributed to modulation of EGCG on P-glycoprotein (P-gp) activity, this kind of PIC micelles could effectively reverse multidrug resistance of cancer cells. These results suggested that EGCG based PIC micelles could effectively overcome DOX induced cardiotoxicity and multidrug resistance.
Therapeutic effects of EGCG: a patent review Chakrawarti, Leewanshi; Agrawal, Rishab; Dang, Shweta ...
Expert opinion on therapeutic patents,
08/2016, Volume:
26, Issue:
8
Journal Article
Peer reviewed
Green tea contains polyphenolic flavanoids such as epigallocatechin-3- gallate (EGCG), epicatechin-3-gallate (ECG), epigallocatechin (EGC) and epicatechin (EC). EGCG is the most abundant and active ...compound in green tea. Extensive research has shown that it has significant antioxidant, anti-carcinogenic, anti-microbial, and neuroprotective properties and has therapeutic potential against various human diseases.
This review focuses on the applications of EGCG alone, and in combination with other compounds, for the treatment of various types of cancers, metabolic, neurodegenerative, and microbial diseases, and discusses its mechanism of action in cell line and animal modesl. Recent advances, which include the use of nanoencapsulated EGCG to enhance the drug delivery and reduce cell toxicity, have also been discussed along with the comprehensive analysis of the specific granted patents associated with EGCG.
Under the current scenario, the role of EGCG as a therapeutic agent is being utilised and new approaches are being formulated to overcome the problem of stability and bioavailability of EGCG. EGCG and its derivatives could be used for the development of drugs for the treatment of cancer, as well as various microbial, metabolic, and neurodegenerative diseases.
The storage process has a significant impact on tea quality. Few is known about effect of storage on quality of oolong tea. This study aimed to assess the effect of different storage times on the key ...chemical components of oolong tea by measuring changes in catechin, free amino acid, and alkaloid content. Variation in the main substances was determined by principal component analysis and heat map analysis. The results revealed notable effects of the storage process on the levels of theanine, epigallocatechin gallate (EGCG), and glutamine. These findings suggest that these compounds could serve as indicators for monitoring changes in oolong tea quality during storage. Additionally, the study observed an increase in the antibacterial ability of tea over time. Correlation analysis indicated that the antibacterial ability against Micrococcus tetragenus and Escherichia coli was influenced by metabolites such as aspartic acid, threonine, serine, gamma-aminobutyric acid, ornithine, alanine, arginine, and EGCG. Overall, this study presents an approach for identifying key metabolites to monitor tea quality effectively with relatively limited data.
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