The effect of quercetin and galangin on glutathione reductase.

Quercetin and galangin can change the activity of glutathione reductase. Quercetin (a catechol structure in the B-ring) and galangin (any hydroxyl group in the B-ring) have different biological activities but, both possess high antioxidant abilities. Quercetin during the antioxidative action, is converted into an oxidized products (o-semiquinone and o-quinone), and subsequently glutathionyl adducts may be formed or SH-enzyme can be inhibited.

Effects of flavonoids on glutathione and glutathione-related enzymes in cisplatin-treated L1210 leukemia cells.

Connections between the ability of quercetin (Qu)and galangin (Ga) to differentially modulate cis-Pt-induced apoptosis and their effects on glutathione system of murine L1210 leukemia cells were studied. The results showed that total glutathione (GSHt) level is increased significantly (cca 123% of control level), both in cells treated with 10 microM Qu and in cells treated with 4 microM cis-Pt and 10 microM Qu in combination. 10 microM Ga had no effect on GSHt content.