Inhibitory effects of Nigella sativa and saffron (Crocus sativus) on chemical carcinogenesis in mice.

Topical application of Nigella sativa and Crocus sativus extracts (common food spices) inhibited two-stage initiation/promotion [dimethylbenz[a]anthracene (DMBA)/croton oil] skin carcinogenesis in mice. A dose of 100 mg/kg body wt of these extracts delayed the onset of papilloma formation and reduced the mean number of papillomas per mouse, respectively. The possibility that these extracts could inhibit the action of 20-methylcholanthrene (MCA)-induced soft tissue sarcomas was evaluated by studying the effect of these extracts on MCA-induced soft tissue sarcomas in albino mice. Intraperitoneal administration of Nigella sativa (100 mg/kg body wt) and oral administration of Crocus sativus (100 mg/kg body wt) 30 days after subcutaneous administration of MCA (745 nmol x 2 days) restricted tumor incidence to 33.3% and 10%, respectively, compared with 100% in MCA-treated controls.