Protection by Nigella sativa against carbon tetrachloride-induced downregulation of hepatic cytochrome P450 isozymes in rats

Nigella sativa (family Ranunculaceae) is an annual plant that has been traditionally used on the Indian subcontinent and in Middle Eastern countries. In this study, we investigated the effect of N. sativa oil on the drug-metabolizing cytochrome P450 (CYP) enzymes and whether it has a protective effect against the acute hepatotoxicity Of CCl(4). Intraperitoneal injection of rats with CCl(4) drastically decreased CYP2E1, CYP2B, CYP3A2, CYP2C11, and CYP1A2 mRNA and protein expressions. Oral administration of 1 ml/kg N. sativa oil every day for one week prior to CCl(4) injection alleviated CCl(4)-induced suppression of CYP2B, CYP3A2, CYP2C11, and CYP1A2. Moreover, CCl(4) increased iNOS and TNF alpha mRNA, while N. sativa oil administration for one week prior to CCl(4) injection downregulated the CCl(4)-induced iNOS mRNA and up-regulated IL-10 mRNA. These results indicate that N. sativa oil administration has a protective effect against the CCl(4)-mediated suppression of hepatic CYPs and that this protective effect is partly due to the downregulation of NO production and up-regulation of the anti-inflammatory IL-10.