ABSTRACTObjectives: The objective of the present study was to evaluate the effects of ethyl acetate extract of M. cochinchinensis seeds (EMC) on 7, 12- Dimethyl Benzanthracene (DMBA) induced mammary carcinoma in Sprague dawley rats and to understand the expression of Bcl-2 an anti apoptotic protein in experimental animals tissues.Methods: The antitumor activity was accessed by the effects of EMC on tumor weight, body weight, enzymic and non enzymic antioxidant parameters such as thiobarbituric acid reactive substances (TBARS) in plasma, superoxide dismutase (SOD), glutathione peroxidase (GPx), reduced glutathione (GSH), catalase (CAT), Vitamin C and Vitamin E in breast tissues and serum. The extract was administered orally at three different doses of low (200 mg/kg), high (400 mg/kg) and low dose with standard. Western blot analysis was carried out for understanding B cell lymphoma-2 (Bcl-2) expressions. EMC was analyzed by HPLC/ESI-MS to comprehend the active constituents.Results: Significant (p < 0.01) reduction in tumor weight and gain in body weight were observed with EMC treatment. Enzymic and non enzymic antioxidant levels in serum as well in breast tissues were revert back significantly (P < 0.01) upon EMC treatment. Over expression of Bcl-2 was observed in tumor control and intensities were reduced in treatment group. HPLC/ESI-MS revealed the presence of Genistein and Daidzein. Conclusion: The ethyl acetate extract of Mucuna cochinchinensis seeds shown anticancer activity in tested animal model. Keywords: Mucuna cochinchinensis, Isoflavones, DMBA, mammary carcinoma, LC-MSÂ