Chemopreventive effect of Chlorella vulgaris in choline deficient diet and ethionine induced liver carcinogenesis in rats

Abstract

Chlorella vulgaris (CV), a unicellular green micro alga, has been widely used as a food supplement and credited with chemopreventive potential against several cancers. CV is reported to have a massive amount of antioxidant such as carotenoids, vitamin E, minerals and enzymes. However its antioxidant effect has not yet been explored in great detail. The aim of this study is to determine the effect of Chlorella vulgaris on the antioxidant enzyme status in liver cancer induced rats. Male Wistar rats (200-250 g) were divided into 8 groups in terms of diet given: control group (normal rat chow), liver cancer induced group (choline deficient diet + 0.1% ethionine in drinking water (CDE)), CV group with three different doses (50, 150 and 300 mg kg-1 body weight) and liver cancer group treated with CV at different concentrations (CDE + CV at 50, 150 and 300 mg kg-1 body weight). Blood sample was taken from rats via orbital sinus at 0, 4, 8 and 12 weeks for the determination of endogenous antioxidant enzymes [superoxide dismutase, (SOD), catalase and glutathione peroxidase, (GPx)] and lipid peroxidation active metabolite, malondialdehyde (MDA). Levels of SOD increased significantly (p<0.05) in CDE group when compared to the control group (normal rat chow) at 8 and 12 weeks of experiment. CV at all doses managed to reduce SOD activity at all weeks of experiment. There was no significant change of catalase level between the control and CDE group at the respective weeks of experiment but CV was able to reduce catalase activity (p<0.05) in CDE rats. There was a significant increase (p<0.05) of GPx activity in the CDE group compared to the control group at week 12. However, CV did not have the same effect on GPx as for SOD and catalase activities whereby GPx activity increased further (p<0.05) in CDE rats when treated with CV. The level of MDA increased significantly (p<0.05) in CDE rats when compared to the control group at week 12. CV at 150 and 300 mg kg-1 body weight managed to reduce MDA level in CDE rats. In conclusion, Chlorella vulgaris may have a protective role in liver cancer induced rats by replacing or compensating the activities of endogenous antioxidant enzymes and by reducing lipid peroxidation. © 2006 Academic Journals Inc., USA.