Special Issue "Catechin in Human Health and Disease"
Deadline for manuscript submissions: 31 July 2018
Catechins are natural polyphenolic compounds that are distributed in a variety of foods and herbs. Tea (Camellia sinensis) is a rich source of catechins, especially epigallocatechin-3-gallate (EGCG), which has many biological activities beneficial for human health. These include anti-cancer, anti-obesity, anti-diabetic, anti-cardiovascular, anti-infectious, hepatoprotective, and neuroprotective effects. A number of human epidemiological and clinical studies on tea have provided evidence for its health benefits and these results have been supported by cell-based and animal experiments, although studies to show conflicting results have also been reported. In addition, detailed molecular mechanisms have been proposed for the action mechanism of tea’s major catechin EGCG. One of the most attractive mechanisms is the one in which reactive oxygen species (ROS) is involved. EGCG is known to have dual actions in relation to ROS as an anti-oxidant and a pro-oxidant. Several lines of evidence have indicated that EGCG can both eliminate ROS by scavenging and enhance ROS production. However, it remains unclear what factor(s) can direct EGCG to act as an anti-oxidant or a pro-oxidant. Catechins and their oligomeric derivatives are also found in apples, persimmons, cacaos, grapes, berries, and so on. However, less information on biological activities of other catechin compounds has been available as compared with EGCG. This Special Issue is devoted to promotion of the understanding of association of catechins and human health. Research articles and reviews related to catechin compounds to reveal their health effects and their mechanistic aspects are welcomed for inclusion in this Special Issue of Molecules. Topics will include cell-based, animal studies, and human studies and special focus will be given to mechanistically-informative studies to be useful to concinnate the dual action of EGCG and other catechin compounds on ROS.
Prof. Dr. Mamoru Isemura
Manuscript Submission Information
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- human health
The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.
Title: Effects of catechins on Alzheimer’s disease: Recent updates and perspectives
Authors: Kazuki Ide 1,2,3, Norihiro Matsuoka 4, Hiroshi Yamada 3, Daisuke Furushima 3, Koji Kawakami 1, 2
Affiliations: 1 Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health, Kyoto University; Kyoto 606–8501, Japan
2 Center for the Promotion of Interdisciplinary Education and Research, Kyoto University; Kyoto
3 Department of Drug Evaluation and Informatics, Graduate School of Pharmaceutical Sciences, University of Shizuoka; Shizuoka 422–8526, Japan
4 Jyoto Hospital, 11-22 Hanatenhigashi 2-chome, Tsurumi-ku Osaka-shi, Osaka, 538-0044, Japan
Abstract: Alzheimer’s disease (AD) is one of the most frequent neurodegenerative disorders worldwide. Its incidence is gradually increasing because of demographic aging. Therefore, AD prevention and modification is important to improve the elderly health status. Oxidative stress is a component of pathological mechanisms underlying AD. It is caused by a disruption of the balance between reactive oxygen species and antioxidant molecules. This imbalance also causes neuroinflammation. Catechins, which are bioactive components of tea, have antioxidative and anti-inflammatory effects. Moreover, their other potential properties related to AD prevention and modification have been reported in in vitro and in vivo studies. Several clinical studies have also been conducted to date. The current review summarizes recent updates and perspectives of the effects of catechins on AD based on the molecular mechanisms and related clinical studies.
Keywords: Alzheimer’s disease, catechins, molecular mechanisms, clinical study
Title: Lipid peroxidation diminishing perspective of isolated oxidized catechins (theaflavins and thearubigins) from black tea in arginine induced renal malfunctional Rats.
Author: Ali Imran
Abstract: Background: Recently oxidative stress induced maladies have amplified owing to sedentary lifestyle and monotonous diet. Introduction of plant based biomolecules may be a suitable strategy to cope with the lipid peroxidation. In this context, black tea polyphenols (theaflavin & thearubigins) are in fame among the scientific community as cost effective therapeutic agents owing to their safety, economics, structural diversity and ability to modulate various lipid peroxidation responses by halting the expression of different metabolic targets. Methods: The mandate of present investigation was to test the synergism among theaflavins & thearubigins against lipid peroxidative indicators both in vitro and in vivo. Purposely, theaflavins and thearubigins were isolated from black tea through solvent partition methods by using different solvents (Aqueous ethanol, Aqueous methanol & Water) and time intervals (30, 60 & 90 minutes) and subjected to in vitro characterization through different antioxidant indices to access the in vitro lipid peroxidation shooting effect of these bioactive moieties. Moreover, individual theaflavins contents also estimate through HPLC. For evaluation of in vivo antioxidant effect, renal malfunction was induced through arginine and forty rats were divided in four groups (10 each after power analysis) and 04 types of diets were given i.e. T0 (control diet without supplementation), T1 (Basic experimental Diet+ theaflavins supplementation @ 1g), T2 (Basic experimental Diet+ Thearubigins supplementation @ 1g) & T3 (Basic experimental Diet+ Supplementation of theaflavins+ thearubigins @ 0.5+0.5 g, respectively) for the period of 56 days. The body weight, lipid profile, glycemic responses, Renal function test, liver function test, antioxidant indices and hematological parameters were estimated at the termination of study.
Results: The results indicated that theaflavins and thearubigins isolation was significantly affected by time of extraction and solvent. In this context, aqueous ethanol at 60 minute extraction interval caused maximum extraction. Likewise, theaflavins isolate exhibited more antioxidant activity as compared to thearubigins. Moreover, the theaflavins and thearubigins based experimental diets imparted significant reduction in Lipid profile, glucose content, renal function tests and TBARS with enhancement in insulin, HDL and hematological parameters. In this context, theaflavin based diet caused maximum reduction in lipid profile and TBARS better as compared to thearubigins and theaflavins + thearubigins based. However, theaflavin+ thearubigins based diet caused highest glucose, urea & creatinine decline and maximum insulin increase & antioxidant indices as compared to other nutraceuticals.
Conclusions: it was deduced that theaflavins & thearubigins have strong antioxidative potential both in in vitro as well as in vivo to tackle the menace associated with lipid peroxidation.
Title: Probing the in vitro antioncogenic potential of isolated oxidized black tea polyphenols(theaflavins and thearubigins) against HCT-116 and HT 460 Colon and lung cancer cells"
Authors: Ali Imran1, Masood sadiq Butt2 and Hang Xiao3
Abstract: Theaflavins and thearubigins are the flavanols-3-ols found in black tea and have promising antioncogenic potential. In current research, these fractions were isolated from black tea and probe for their in vitro inhibitory effect against colon and lung cancer cell lines. Results indicated that theaflavin, thearubigins and their combination caused significant inhibition in cell viability in dose dependent manner however, theaflavin imparted maximum reduction in cell viability of HCT 116 & HT460. The flow cytometry results indicated that theaflavin, thearubigins and their combination caused substantial cell arrest at G2/M phase. The effect was more obvious in lung cancer cells (HT 460) as compared to colon cells (HCT 116). Likewise, all treatments caused apoptosis however, the combination of theaflavin and thearubigins showed highest apoptotic ability in comparison of their alone treatments. Conclusively, it was revealed that theaflavin and thearubigins showed synergistic effect and significantly inhibited the cell proliferation of HCT 116 & HT 460 in time and dose dependent manner by inducing apoptosis and cell cycle arrest however, theaflavin exhibited more pronounced effect.
Keywords: HCT 116; HT 460; Lung cancer; Theaflavins; Thearubigins; synergistic effects
Tentative title: Roles of binding affinity of epigallocatechin-3-O-gallate with proteins in health benefits of green tea
Authors: Kouichi Saeki, Sumio Hayakawa, Shogo Nakano, Sohei Itoh, Yumiko Oishi and Mamoru Isemura
Abstract: Green tea has been shown to have beneficial effects on a variety of diseases such as cancer, obesity, diabetes, cardiovascular disease, and neurodegenerative disease. Green tea component, epigallocatechin-3-O-gallate (EGCG), has been believed to contribute to these effects through antioxidative and prooxidative actions. In addition, several lines of evidence have demonstrated that the binding affinity of EGCG to proteins involves in its action mechanism. There are several methods to demonstrate EGCG-protein bindings. These include dot assays, affinity chromatography, surface plasmon resonance, and computational docking analysis. The present review is aimed to update information from such studies on EGCG-protein interaction and discuss the molecular mechanism by which green tea exerts its health-promoting actions.