ANTITUMOR-ACTIVITY OF DIALLYL SULFIDE ON POLYCYCLIC AROMATIC HYDROCARBON-INDUCED MOUSE SKIN CARCINOGENESIS

Diallyl sulfide (DAS), a major flavour component of garlic, is known t o modulate xenobiotic metabolism and possess antitoxic, bactericidal, antineoplastic, hypolipidemic and hypocholesteromic effects. In the pr esent study, the anticarcinogenic activity of DAS on a 7,12-dimethylbe nzanthracene (DMBA)- or benzo[a]pyrene (B(a)P)-induced mouse skin mode l of carcinogenesis was evaluated. DAS was applied topically either 1 h prior to or 1 h after the administration of DMBA or B(a)P. A signifi cant protection from neoplasia was observed in DAS- and DMBA/B(a)P-exp osed animals when DAS was applied topically compared to the animals ex posed only to DMBA/B(a)P. In the animals where DAS was applied 1 h pri or to the application of DMBA, a lower magnitude of neoplasia was reco rded in terms of the cumulative number of tumours and average number o f tumours per mouse during the entire period of study (28 weeks) compa red to the animals exposed to DAS 1 h later, while in B(a)P-exposed an imals, the antitumorigenic potential of DAS was more evident in the mi ce treated with DAS 1 h after the B(a)P exposure compared to the anima ls treated with DAS 1 h prior to B(a)P. The antitumour activity of DAS was of a much higher magnitude in B(a)P-induced carcinogenesis in com parison to animals exposed to DMBA in terms of tumour incidence, cumul ative number of tumours and average number of tumours per mouse. The r esults suggest that DAS has a protective effect in PAM-induced mouse s kin carcinogenesis. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.