Epimerization of epigallocatechin gallate to gallocatechin gallate and its anti-diabetic activity

Xie, Lianwu; Guo, Yaping; Cai, Bo; Yang, Jing

doi:10.1007/s00044-012-0352-z

Cited by 21 publications

(18 citation statements)

References 29 publications

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“…For flavonoids, we selected gallocatechin gallate (GCG) and theaflavin (TF) (Figure S1C,D). TF is one of the main phenolic components found in fermented black tea, whereas GCG is an epimer of EGCG, a major polyphenol in green tea and a well-known inhibitor of Aβ aggregation, but it is more stable and bioactive [30]. Resveratrol has been reported extensively in literature, thus providing us a good reference point for our current study [26,28].…”

Section: Introductionmentioning

confidence: 99%

Polyphenols Modulate Alzheimer’s Amyloid Beta Aggregation in a Structure-Dependent Manner

et al. 2019

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Some polyphenols, which are common natural compounds in fruits, vegetables, seeds, and oils, have been considered as potent inhibitors of amyloid beta (Aβ) aggregation, one critical pathogenic event in Alzheimer’s disease (AD). However, the mechanisms by which polyphenols affect aggregation are not fully understood. In this study, we aimed to investigate the effect of two classes of polyphenols (flavonoids and stilbenes) on the self-assembly of Aβ_42, in particular, how this relates to structure. We found that the flavonoids gallocatechin gallate (GCG) and theaflavin (TF) could completely inhibit Aβ aggregation, while two stilbenes, resveratrol and its glucoside derivative piceid, could also suppress Aβ aggregation, but to a much lesser extent. Intriguingly, resveratrol accelerated the formation of Aβ fibrils before its decreasing effect on fibrillation was detected. Atomic force microscopy (AFM) images showed a huge mass of long and thin Aβ fibrils formed in the presence of resveratrol. Although the morphology was the same in the presence of piceid, the fibrils were sparse in the presence of picead. In the presence of flavonoids, Aβ morphology was unchanged from prior to incubation (0 h), in agreement with amyloid beta kinetics analysis using thioflavin-T fluorescence assay. The electrochemical data showed a higher ability of GCG and TF to interact with Aβ than resveratrol and piceid, which could be attributed to the presence of more aromatic rings and hydroxyl groups. In addition, the two flavonoids exhibited a similar propensity for Aβ aggregation, despite having some differences in their structure. However, in the case of stilbenes, the addition of a glucoside at C-7 slightly decreased anti-Aβ aggregation property compared to resveratrol. These findings contribute to a better understanding of the essential structural features of polyphenols required for inhibiting Aβ aggregation, and the possible mechanisms for modulating aggregation.

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Section: Introductionmentioning

confidence: 99%

Polyphenols Modulate Alzheimer’s Amyloid Beta Aggregation in a Structure-Dependent Manner

et al. 2019

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“…Even though the fatty acid profiles of both these oils are the same, VCO has a higher amount of polyphenolic antioxidants such as caffeic acid, ferulic acid, syringic acid, catechin and epigallocatechin (Marina et al 2008). These polyphenolics are well known for their antidiabetic and insulin sensitizing effects (Ramar et al 2012;Srinivasan et al 2014;Xie et al 2013). Supplementation of VCO has been reported to have beneficial effects on lipid parameters by reducing lipogenesis and enhancing the rate of fatty acid catabolism (Arunima and Rajamohan 2012).…”

Section: Introductionmentioning

confidence: 99%

Virgin coconut oil maintains redox status and improves glycemic conditions in high fructose fed rats

et al. 2015

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Virgin Coconut Oil (VCO), extracted from fresh coconut kernel possess similar fatty acid composition to that of Copra Oil (CO), a product of dried kernel. Although CO forms the predominant dietary constituent in south India, VCO is being promoted for healthy life due to its constituent antioxidant molecules. High fructose containing CO is an established model for insulin resistance and steatohepatitis in rodents. In this study, replacement of CO with VCO in high fructose diet markedly improved the glucose metabolism and dyslipidemia. The animals fed VCO diet had only 17 % increase in blood glucose level compared to CO fed animals (46 %). Increased level of GSH and antioxidant enzyme activities in VCO fed rats indicate improved hepatic redox status. Reduced lipid peroxidation and carbonyl adducts in VCO fed rats well corroborate with the histopathological findings that hepatic damage and steatosis were comparatively reduced than the CO fed animals. These results suggest that VCO could be an efficient nutraceutical in preventing the development of diet induced insulin resistance and associated complications possibly through its antioxidant efficacy.

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“…This is because Aspergillus produces citric acid from carbon sources (Xu et al, 1989). The acidity of the basal medium was increased to pH 6.0 because catechins are unstable under alkaline conditions, whereas they are stable under acidic conditions (Zhong et al, 2008;Xie et al, 2013).…”

Section: Production Of Teadenols On the Modified Czapek-dox Catechin-mentioning

confidence: 99%

“…Additionally, EGCG, the most abundant catechin component (>50%) of tea leaves (Wang and Helliwell, 2000;Xie et al, 2013), was used as a starting material. This ensured that GCG was present in the medium, as a portion of the EGCG was converted into GCG, the C-2 epimer of EGCG, by epimerization during sterilization of the medium by autoclaving (Ikeda et al, 2003;Huang et al, 2004).…”

Section: Production Of Teadenols On the Modified Czapek-dox Catechin-mentioning

confidence: 99%

Simple Method for the Preparation of Teadenols A and B by a Combined Process of Submerged Culture with <i>Aspergillus</i> sp. and Chromatographic Separation

Song

Miyazaki

Yoshida

2017

FSTR

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Methods for the production and isolation of the tea components teadenols A and B were developed because of their potential anti-metabolic syndrome activity. Aspergillus sp. (FARM AP-21280) was inoculated to a modified Czapek-Dox medium containing (-)-epigallocatechin 3-O-gallate (EGCG) and (-)-gallocatechin 3-O-gallate (GCG) and incubated at 25℃. The maximum contents of the teadenols were observed at 19 days, and the contents increased depending on the initial EGCG concentration. The addition of green tea powder to the medium enhanced the production of teadenols. In the modified Czapek-Dox medium containing 5.0% EGCG and 1.0% green tea powder, teadenols A and B were efficiently produced at 3.22 ± 0.23 and 4.49 ± 0.38 mg/mL, respectively. The teadenols were purified by sequential chromatography on Sephadex LH-20 and InertSustain™ C18 columns. After purification by preparative HPLC, 0.27 g teadenol A (29.7% recovery) and 0.45 g teadenol B (42.9% recovery) were obtained from the 970 mL culture filtrate.

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Epimerization of epigallocatechin gallate to gallocatechin gallate and its anti-diabetic activity

Cited by 21 publications

References 29 publications

Polyphenols Modulate Alzheimer’s Amyloid Beta Aggregation in a Structure-Dependent Manner

Polyphenols Modulate Alzheimer’s Amyloid Beta Aggregation in a Structure-Dependent Manner

Virgin coconut oil maintains redox status and improves glycemic conditions in high fructose fed rats

Simple Method for the Preparation of Teadenols A and B by a Combined Process of Submerged Culture with <i>Aspergillus</i> sp. and Chromatographic Separation

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