Enhancement of glutathione S-transferase using diallyl sulfide from garlic in Hepa-1c1c7 cells

Abstract

Modification of the expression of xenobiotic metabolizing enzymes, such as glutathione S-transferase (GST), is thought to be one of the mechanisms of the anticarcinogenic effect of garlic. To obtain further insight into the induction of the GST enzyme and on the anticarcinogenic action of garlic, we examined the effect of daillyl sulfide (DAS), an organosulfur compound derived from garlic, on the induction of GST in the murine hepatoma cells (Hepa-1c1c7), which is sensitive to the xenobiotics. We observed that the GST enzyme activity was enhanced after treatment with 5 mM DAS for 16, 24 and 48 hours. Dose-response experiments demonstrated that the GST enzyme activity increased with increasing concentrations of DAS. Furthermore, Western blotting analysis revealed that three GST isoenzyme proteins, GST-α, GST-μ and GST-π, tended to increase with increasing DAS concentrations. In summary, the results suggest that GST enzyme activity can be enhanced by DAS in Hepa-1c1c7 cells, and the increased expression of the GST isoenzyme proteins contributed to the augmentation of the corresponding enzyme activity. The increased GST activity may explain, at lease in part, the anticarcinogenic effect of garlic.