EFFECT OF DIALLYL SULFIDE ON TOAD LIVER-TUMOR INDUCED BY 7,12-DIMETHYLBENZ(A)ANTHRACENE

Hepatocellular carcinoma were recognized in the toad, Bufo viridis, in 18 cases out of 50 cases by administration of 1mg of 7,12-dimethylben z(a)anthracene (DMBA)/toad, once/week for 12 weeks. In contrast, toads treated with DMBA at the same dose level and diallyl sulfide (DAS), 5 mg (3hr. prior to carcinogen)/toad, once/week for 12 showed a signific ant lower incidence of liver tumors, 9 out of 50 cases. However, DAS ( 10 mg/toad, once/week for 12 weeks) was ineffective when administered 3hr. after the carcinogen (DMBA), 17 cases out of 50 cases. Neither tu mor growth nor neoplastic changes were observed in toads treated with olive oil and used as a control. It is concluded that DAS have inhibit ory effect on toad liver tumor during initiation.