Inhibition of the benzo[a]pyrene-induced toxicity by allyl sulfides in human epidermal keratinocytes

Diallyl sulfide (DAS) and diallyl disulfide (DADS) at 25 g ml^–1decreased the benzo[a]pyrene (B[a]P)-induced colony growth inhibition of human epidermal keratinocytes. DAS and DADS decreased B[a]P-DNA and B[a]P-protein adducts by 65% and 49–55%, respectively. The B[a]P-induced ethoxyresorufin O-deethylase activity, a marker enzyme for cytochrome P450 1, was decreased from 3 to 1.7–1.9 nmol min^–1 mg^–1 microsomal protein by DAS and DADS treatments. The activity of glutathione S-transferase, a detoxifying enzyme for B[a]P, but was decreased by DADS, but was unaffected by DAS.