Biol. Pharm. Bull. 28(4) 740—743 (2005)

nosed malignancy, and second leading cause of cancer related deaths in the United States. Among them, approximately half of the patients develop incurable condition with no effective treatment. Current therapy for advanced prostate cancer is largely based on androgen deprivation. However, as with androgen ablation therapy, the responses are generally of short duration and resistant to therapy eventually results in progression. In this situation, control of prostate cancer through chemoprevention and intervention strategies is highly desirable. Induction of apoptosis in cancerous cells is considered to be very useful in the management and therapy of the disease. A wide variety of natural substances have been recognized to possess the ability to induce apoptosis in various cancerous cells. Epidemiological studies suggest that garlic consumption is associated with a reduced risk of cancer incidence. These anticarcinogenic effects, as other biological properties of garlic are attributed to the presence of specific organosulfur compounds. Among these, diallyl disulfide is a major volatile organosulfur compound of garlic oil. Many studies on animal model showed its protective effect against chemically induced toxicity and also against carcinogenesis. In the present study we investigated the effect of organosulfur compound of garlic, diallyl disulfide on the inhibition of proliferation and induction of apoptosis in human prostate cancer PC-3 cells.