Inhibition of human glutathione S-transferase P1-1 by the flavonoid quercetin

In the present study, the inhibition of human glutathione S-transferase P1-1 (GSTP1-1) by the flavonoid quercetin has been investigated. The results show a time- and concentration-dependent inhibition of GSTP1-1 by quercetin. GSTP1-1 activity is completely inhibited upon 1 h incubation with 100 μM quercetin or 2 h incubation with 25 μM quercetin...

Regioselectivity of phase II metabolism of luteolin and quercetin by UDP-glucuronosyl transferases

Interactions of prostaglandin A2 with the glutathione-mediated biotransformation system

The cyclopentenone prostaglandin A2 (PGA2) is known to inhibit cell proliferation, and metabolism of this compound thus might be important in controlling its ultimate function. The glutathione-related metabolism of PGA2 was therefore investigated both with purified glutathione S-transferase P1-1 (GSTP1-1) and with IGR-39 human melanoma cells....

The role of biotransformation in dietary (anti)carcinogenesis

The fact that dietary compounds influence the susceptibility of human beings to cancer, is widely accepted. One of the possible mechanisms that is responsible for these (anti)carcinogenic effects is that dietary constituents may modulate biotransformation enzymes, thereby affecting the (anti)carcinogenic potential of other compounds. This...

Interactions of prostaglandin A2 with the glutathione-mediated biotransformation system

The role of biotransformation in dietary (anti)carcinogenesis

GSTP1-1 stereospecifically catalyzes glutathione conjugation of ethacrynic acid

GSTP1-1 stereospecifically catalyzes glutathione conjugation of ethacrynic acid

Using 1H NMR two diastereoisomers of the ethacrynic acid glutathione conjugate (EASG) as well as ethacrynic acid (EA) could be distinguished and quantified individually. Chemically prepared EASG consists of equal amounts of both diastereoisomers. GSTP1-1 stereospecifically catalyzes formation of one of the diastereoisomers (A). The GSTP1-1...

Irreversible inhibition of cytosolic glutathione S-transferases

In vitro inhibition of rat and human glutathione S-transferase isoenzymes by disulfiram and diethyldithiocarbamate

The drug disulfiram (DSF, Antabuse®) has been used in the therapy of alcohol abuse. It is a potent inhibitor of aldehyde dehydrogenase. Its reduced form, diethyldithiocarbamate (DDTC), and further metabolites show similar activities. DSF and DDTC have also been widely used to inhibit mixed-function oxidases. In this study, the reversible...

Inhibition of glutathione S-transferase activity in human melanoma cells by alfa, beta-unsaturated carbonyl derivatives: Effects of acrolein, cinnamaldehyde, citral, crotonaldehyde, curcumin, ethacrynic acid, and trans-2-hexenal

The glutathione S-transferase (GST) activity towards 1-chloro-2,4-dinitrobenzene in intact human IGR-39 melanoma cells was determined by the quantification by HPLC-analysis of the excreted glutathione (GSH) conjugate (S-(2,4-dinitrophenyl)glutathione; DNPSG). The major GST subunit expressed in these melanoma cells is the π-class GST subunit P1....