Anti-tumor activity of rosmarinic acid in 7,12-dimethylbenz(a)anthracene (DMBA) induced skin carcinogenesis in Swiss albino mice.

Aim of the present study was to evaluate the anti-tumor effect of orally administered rosmarinic acid in 7,12-dimethylbenz(a)anthracene (DMBA) induced skin carcinogenesis in Swiss albino mice. Phase I and II detoxication agents, lipid peroxidation byproducts, antioxidants and apoptotic biomarkers were used to assess chemopreventive efficacy of rosmarinic acid in DMBA induced skin carcinogenesis. Skin squamous cell carcinoma was induced at the shaved back of mice by applying DMBA (20 microg in 0.1 mL acetone) twice weekly for 8 weeks. Tumor formation (100%) was observed within 15 weeks of treatment in DMBA alone. Marked alterations in the status of above mentioned biomarkers were observed in tumor bearing mice. Oral administration of rosmarinic acid completely prevented the formation of skin tumors during DMBA-induced mouse skin carcinogenesis. Also, oral administration of rosmarinic acid brought back the status of phase I and phase II detoxication agents, lipid peroxidation byproducts, antioxidants and apoptotic markers (p53, Bcl-2, caspase-3 and caspase-9) in DMBA treated mice. Results of the present study suggested that rosmarinic acid had potent anticancer, anti-lipid peroxidative and apoptotic effect in DMBA-induced skin carcinogenesis.