Silymarin Attenuates Chromate (VI)-Induced Toxicity on Human Peripheral Blood Lymphocytes in-Vitro

Hexavalent chromium compounds are well known human carcinogens. The effects of pretreatment with the flavanolignan silymarin (25, 50, 100 ig/ml) to counteract the toxic effects of Chromate (VI) (10 ig/ml) was studied on human peripheral blood lymphocytes cultured in vitro. Standard cell proliferation and cytotoxicity assays like MTT assay, NBT reduction test, trypan blue dye exclusion test, estimation of the levels of lipid peroxides and nitric oxide was performed to study the detrimental effect of chromate (VI) on the proliferation of the lymphocytes and to assess the degree of protection offered by pretreatment with silymarin. Chromate (VI) treatment (10ig/ml) resulted in statistically significant decrease in cell proliferation (P < 0.001), increase in cytotoxicity and increased oxidative stress (P < 0.001). Pretreatment with silymarin (100 ig/ml) for 15 minutes prior to chromate exposure was able to significantly prevent against chromate (VI)-induced toxicity which was confirmed by all the above mentioned assays. The results of our study give leads about the possible use of silymarin as a diet based prophylactic regimen to counteract the toxic effects of chromate in workers employed in chromium based industries.