Epimerization of Tea Catechins under Weakly Acidic and Alkaline Conditions

Ishino, Nobuyoshi; Yanase, Emiko; Nakatsuka, Shin‐ichi

doi:10.1271/bbb.90884

Cited by 30 publications

(26 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both the natural and the non-natural catechins have hydroxyl groups (two or three) at the 3′-, 4′-, and/or 5′- positions of the B ring and a hydroxyl group at the 3-position of the C ring. Epimerization at the 2-position of the C ring can be induced by heat or changes in pH [ 11 ]. Investigation of the interactions between proteins and various catechin derivatives and the stereoisomers can be expected to lead to a better understanding of the mechanisms by which these compounds are recognized by proteins.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic and computational analyses reveal the functional roles of the galloyl group of tea catechins in molecular recognition

et al. 2018

View full text Add to dashboard Cite

Catechins, biologically active polyphenols in green tea, exhibit various biological activities, such as anticancer and antiviral activities, arising from interactions with functional proteins. However, the molecular details of these interactions remain unclear. In this study, we investigated the interactions between human serum albumin (HSA) and various catechins, including some with a galloyl group, by means of isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), and docking simulations. Our results indicate that the galloyl group was important for recognition by HSA and was responsible for enthalpic gains derived from a larger buried surface area and more van der Waals contacts. Thus, our thermodynamic and computational analyses suggest that the galloyl group plays important functional roles in the specific binding of catechins to proteins, implying that the biological activities of these compounds may be due in part to the physicochemical characteristics of the galloyl group.

show abstract

Section: Introductionmentioning

confidence: 99%

Thermodynamic and computational analyses reveal the functional roles of the galloyl group of tea catechins in molecular recognition

et al. 2018

View full text Add to dashboard Cite

show abstract

“…EGCg, EGC, ECg and EC are the primary catechins in tea leaf (Beecher et al, 1999), but some other minor catechins and tannins also exist. Moreover, it is known that EGCg, EGC, ECg or EC can epimerize and change to (-)-gallocatechin gallate (GCg), (-)-gallocatechin (GC), (-)-catechin gallate (Cg) and (-)-catechin (C) when heated (Ishino et al, 2010). Because the tea extract used in this study was prepared with boiling water, it is possible that GCg, GC, Cg and C were present in the tea extract.…”

Section: Resultsmentioning

confidence: 99%

Tea Extract Modulates the Expression of DC-STAMP mRNA in RAW264.7 Cells

Matsuda

Fujita

Hara

et al. 2015

FSTR

View full text Add to dashboard Cite

“…As a result, the stereochemistry of the bond linking the B- and C-rings inverts, converting EGCG to (−)-gallocatechin gallate (GCG) (Sang et al, 2005b; Ishino et al, 2010). Despite this stereochemical alteration, GCG poisons topoisomerase II with an activity that is similar to that of EGCG (Timmel et al, 2013).…”

Section: Bioflavonoidsmentioning

confidence: 99%

Phytochemicals as anticancer and chemopreventive topoisomerase II poisons

2013

View full text Add to dashboard Cite

Phytochemicals are a rich source of anticancer drugs and chemopreventive agents. Several of these chemicals appear to exert at least some of their effects through interactions with topoisomerase II, an essential enzyme that regulates DNA supercoiling and removes knots and tangles from the genome. Topoisomerase II-active phytochemicals function by stabilizing covalent protein-cleaved DNA complexes that are intermediates in the catalytic cycle of the enzyme. As a result, these compounds convert topoisomerase II to a cellular toxin that fragments the genome. Because of their mode of action, they are referred to as topoisomerase II poisons as opposed to catalytic inhibitors. The first sections of this article discuss DNA topology, the catalytic cycle of topoisomerase II, and the two mechanisms (interfacial vs. covalent) by which different classes of topoisomerase II poisons alter enzyme activity. Subsequent sections discuss the effects of several phytochemicals on the type II enzyme, including demethyl-epipodophyllotoxins (semisynthetic anticancer drugs) as well as flavones, flavonols, isoflavones, catechins, isothiocyanates, and curcumin (dietary chemopreventive agents). Finally, the leukemogenic potential of topoisomerase II-targeted phytochemicals is described.

show abstract

Epimerization of Tea Catechins under Weakly Acidic and Alkaline Conditions

Cited by 30 publications

References 10 publications

Thermodynamic and computational analyses reveal the functional roles of the galloyl group of tea catechins in molecular recognition

Thermodynamic and computational analyses reveal the functional roles of the galloyl group of tea catechins in molecular recognition

Tea Extract Modulates the Expression of DC-STAMP mRNA in RAW264.7 Cells

Phytochemicals as anticancer and chemopreventive topoisomerase II poisons

Contact Info

Product

Resources

About