Nigella sativa L. oil: Study of its toxicity, antiradical activity, and effect on circulating xanthine oxidoreductase

Introduction: Nigella sativa L. is a widely used medicinal plant throughout the world. The low toxic effects and low price of this plant make it an excellent treatment choice for many diseases. The present study aims to investigate the hepatoprotective effect of N. sativa L. total oil (TO) and its neutral lipid fraction (NLF) via the estimation of circulating xanthine oxidoreductase (XOR) level and anti-XOR antibodies titer. Methods: Antiradical activities of TO and NLF, in vitro, were carried out using three reactive oxygen species (ROS), superoxide anion, hydroxyl radical, and hydrogen peroxide. In vivo study was conducted to determine the possible protective effects of TO and NLF against ethanol-induced hepatotoxicity in rats feeding Lieber-DeCarli liquid diet in both sera and liver homogenate. Before conducting the hepatoprotective effects, we assessed the toxicity of our extracts using the same animal model. The administrated doses of 400 mg/kg for TO and 300 mg/kg for NLF showed no toxic effects. Results: ELISA assay indicated a significant increase (P<0.001) in the level of XOR and the titer of anti-XOR antibodies in rats treated with ethanol compared to the control group. After treatment with TO and NLF, the titer of anti-XOR antibodies and the level of XOR decreased significantly compared to the control group. Conclusion: XOR plays an important role in alcohol liver pathologies as a major source of free radicals. In addition, TO and NLF have significant potential as liver protective agents and might be utilized as new antioxidant therapeutics.