Please use this identifier to cite or link to this item:
Title: Inhibitory effects of plant polyphenols on rat liver glutathione S- transferases
Authors: Zhang, K.
Das, N.P. 
Keywords: flavonoid
glutathione S-transferase
rat liver
tannic acid
Issue Date: 1994
Citation: Zhang, K., Das, N.P. (1994). Inhibitory effects of plant polyphenols on rat liver glutathione S- transferases. Biochemical Pharmacology 47 (11) : 2063-2068. ScholarBank@NUS Repository.
Abstract: Several novel naturally occurring flavonoids and other polyphenols exerted varying degrees of concentration-dependent inhibition on uncharacterized rat liver glutathione S-transferase (EC, GST) isoforms. The order of inhibitory potencies of the five most potent polyphenols was tannic acid > 2- hydroxyl chalcone > butein > morin > quercetin, and their IC50 values were 1.044, 6.758, 9.033, 13.710 and 18.732 μM, respectively. Their inhibitions were reversible, as indicated by dialysis experiments. The optimum pH for the inhibitions by four of the compounds (tannic acid, butein, 2-hydroxyl chalcone and morin) was in the range of pH 6.0 to 6.5, but for quercetin the optimum pH was 8.0. These potent inhibitors possess one or more of the following chemical structural features: (a) polyhydroxylation substitutions, (b) absence of a sugar moiety, (c) for the chalcones, the presence of an open C-ring and hydroxylation at either the C-2 or C-3 position, (d) for the flavonoids, the attachment of the B-ring to C-2, and (e) a double bond between C-2 and C-3. Butein exhibited a non-competitive inhibition toward both glutathione (GSH) and 1-chloro-2,4-dinitrobenzene (CDNB). Interestingly, tannic acid showed a non-competitive inhibition toward CDNB but a competitive inhibition toward GSH. The inhibitory potency of tannic acid on rat liver GSTs was concentration and substrate dependent. Using CDNB, p-nitrobenzyl chloride, 4-nitropyridine-N-oxide, and ethacrynic acid as substrates, the IC50 values for tannic acid were 1.044, 11.151, 20.206, and 57.664 μM, respectively.
Source Title: Biochemical Pharmacology
ISSN: 00062952
DOI: 10.1016/0006-2952(94)90082-5
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.


checked on Mar 18, 2019


checked on Mar 18, 2019

Page view(s)

checked on Dec 8, 2018

Google ScholarTM



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.