Evaluation of the protective effect of Nigella sativa extract and its primary active component thymoquinone against DMBA-induced breast cancer in female rats

INTRODUCTION: The historical use of black cumin seed (Nigella sativa) dates back centuries, being embedded in Arabian culture and having a long history of unsurpassed medicinal value with versatility to treat a wide range of ailments. Thymoquinone (TQ) is now known to be the primary active constituent of black cumin seed oil (BCS oil) responsible for its medicinal effects and also showing promise for treatment of cancer. MATERIAL AND METHODS: In the current study, we have studied the effects of TQ and BCS oil on tumor markers (MDA, LDH, ALP and AST), histopathological alterations and the regulation of several genes (Brca1, Brca2, Id-1 and P53 mutation) related to breast cancer in female rats induced by 7,12-dimethylbenz[a]anthracene (DMBA) treatment. Rats received a single dose (65 mg/kg b.w.) of DMBA via an intragastric tube to induce breast cancer. Animals that received DMBA were treated orally with 1, 5, 10 mg/kg of TQ or BCS oil via an intragastric tube three times per week for 4 months. RESULTS: We found that TQ and then BCS reduced the rate of tumor markers (levels of MDA and LDH as well as ALP and AST activities), inhibited the histopathological alterations and decreased the expression of the Brca1, Brca2, Id-1 and P53 mutations in mammary tissues of female rats induced by DMBA treatment. CONCLUSIONS: The results suggest that TQ and BCS oil exert a protective effect against breast carcinogens. The antioxidant property of TQ and BCS oil is mediated by their actions and investigating other underlying mechanisms merits further studies.