Antitumorigenic Potential of Diallyl Sulfide in Ehrlich Ascites Tumor Bearing Mice

Objective To study the effects of diallyl sulfide (DAS), an organosulfur compoundpresent in garlic (Allium sativum), on the life span of ehrlich ascites (EA) tumor bearingSwiss albino mice, cytotoxicity and angiogenesis. Methods EA tumor cells weremaintained by serial transplantation in peritoneal cavity of male Swiss albino mice. EAtumor cells were inoculated at concentrations of 1× 106 EA cells, 2.5× 106 EA cells and5× 106 EA cells. DAS was given in 0.2 ml normal saline i. p., daily for seven days followedone hour later by inoculation with EA cells in respective groups. Results The resultsrevealed that administration of DAS increased the life span of EA tumor bearing animals bymore than 25 percent. A significant dose dependant cytotoxic response of DAS was alsoobserved on EA tumor cells. DAS was also found to inhibit the angiogenesis in EA tumorbearing mice in a dose dependent manner. Conclusion It is suggested that DAS may exertits anticarcinogenic effects by more than one mechanism and is a useful chemopreventiveand chemotherapeutic agent.

Inhibition of Carcinogen Induced Activity of γ-glutamyl Transpeptidase by CertainDietary Constituents in Mouse Skin

Cancer chemoprevention, a desirable and important facet of biomedical research, provides a practical approach to identify potentially useful inhibitors of cancer development, and offers an opporiunity to study the mechanism of carcinogenesis. During the recent Past a number of compounds have been tested for their anticarcinogenic potential specially constituents of our diet. The enzyme γglutamyl transpeptidase (GGT) which catalyses the transfer of glutamyl groups of peptides to other peptides and amino acid and has been proposed as a marker of cell proliferation and neoplasia. It also serves as a tool to evaluate the carcinogenic and cocarcinogenic potential of environmental toxicants. In the present investigations, CGT activity induced by careinogenic polycyclic aromatic hydmiarbons, viz. 7, 12-dimethylbenz(a) anthracene (DMBA) and benzo(a) pyrene (BaP) was significantly inhibited by diallylsulfide (DAS) and indole-3-carbnol (I3C) in mouse skin. DAS and 13C are constituents of garlic and cruciferous vegetables respectively. A significant iIthibition in GGT levels was also observed in a strong mitogen (12-o-tetradecanoyl phorbol-13-acetate) induced activity in mouse skin by pretreatment with DAS/13C. Therefore these dietary constituents seem to be strong modifiers of chemically induced carcinogenesis

Effect of Nicotinamide on 12-O-tetradecanoyl-phorbol-13-acetate Exposed Mouse Skin Endonuclease Activity and DNA Synthesis

Nicotinamide (NA), a relatively nontoxic compound, has been shown to inhibit tumor development, induce differentiation, increase the sensitization of the anticancer drug resistant cancer cells and is being used in different skin ailments. But there are not many reports on its mechanism of action. Here we report that NA induced endonuclease activity. This endonuclease induction by NA appeared to be dose dependent and a function of time. As evident by the use of modifiers of DNase I, this endonuclease appeared to be like DNase type I. Increased [3H] thymidine incorporation in DNA in the presence of NA is possibly a consequence of increased 3_OH'nicks due to increased DNA fragmentation by increased endonuclease activity. The present results would be of help in the better understanding of the mechanism of NA action and its improved use in cancer control.