Inhibitory effect of crocetin on benzo(a)pyrene genotoxicity and neoplastic transformation in C3H10T1/2 cells.

Crocetin is a major component in the fruit of Gardenia jasminoides Ellis, a Chinese herbal medicine. In the work, we investigate the protective action and mechanism against benzo(a)pyrene [B(a)P]-induced genotoxicity and neoplastic transformation with a non-toxic dose of crocetin (0.01-0.10 mM) for 1 hour prior to the administration of 0.1 mM B(a)P. B(a)P genotoxicity was inhibited significantly by crocetin in a dose responsive manner. Pretreating C3H10T1/2 cells with crocetin (0.1 mM) also caused a decrease in the covalent binding of B(a)P-diol-epoxide to DNA, to about half that of cells without crocetin treatment. Crocetin also inhibited B(a)P-induced transformations. When the culture was treated with crocetin (0.01, 0.05 and 0.10 mM) for 7 days, the transformation frequencies were lower than that of the culture without crocetin treatment. Furthermore, pretreating cells with crocetin (0.01-0.10 mM) also caused an increase in the activity of GSH S-transferase (GST) to 18-71% that of the cells without crocetin treatment. These results suggest that the inhibition by crocetin of B(a)P-induced genotoxicity and neoplastic transformation in C3H10T1/2 cells is due to a mechanism that increases the activity of GST and decreases the formation of a B(a)P-DNA adduct.