Antitumorigenic activity of Styela clava on DMH-induced colon carcinogenesis in male SD Rat
Colorectal cancer is the third most common malignant neoplasm in the world. Much attention has been focused on reducing colon cancer risk through medical properties of natural compound that could act as anticarcinogens . Styela clava (also called as rough sea squirt or leathery tunicate) is thought to be native to the northwest Pacific including Korea and widely distributed in parts of northwestern Europe, North America and Australia . Recently, we observed that Styela clava extract has antigenotoxic and anticarcinogenic effects from in vitro experiments. In this study, we evaluated the effect of Styela clava on the formation of aberrant crypt foci (ACF) induced by dimethylhydrazine (DMH) and DMH induced DNA damage (by comet assay) in male SD rats. The animals were divided into three groups and fed high-fat and low fiber diet (100g lard + 20g cellulose/kg diet) without (normal control and DMH control) or with a 3% (w/w) of lyophilized Styela clava powder (DMH+SC). One week after beginning the diets, rats were treated with DMH (30mg/kg, s.c.) for 6 weeks except for normal control group, which was treated saline instead; dietary treatments were continued for the entire experiment. 9 weeks after DMH injection, administration of Styela clava resulted in reduction of ACF numbers, to 62.5% of the carcinogen control value (9.14±2.34 vs. 3.43±0.84). Styela clava supplementation induced antigenotoxic effect on DMH-induced DNA damage in the blood cell (% tail intensity: 6.79±0.26 vs. 5.96±0.21). These data indicate that Styela clava exerts a protective effect on the process of colon carcinogenesis, possibly by suppressing the DMH-induced DNA damage in blood cell and the development of preneoplastic lesions in colon.
References: 1. Ji, B.T. et al. (1998) Cancer Epidemiol. Biomarkers Prev. 7: 661–666.
2. Lee, E. H. (1985) Korean. J. Food Sci. Tec. 17: 289–294.