Evaluation of Antioxidant and Anti-Xanthine Oxidoreductase Activities of Nigella sativa Linn seeds’ extracts

Abstract

Nigella sativa , one of the most studied medicinal plants over the world, possesses a number of well established pharmacological properties. In this study, we have prepared different extracts from Nigella sativa’s seeds. The results show that hexane (HxE), chloroform (ChE) and ethyl acetate (AcE) extracts present an apparent inhibitory effect on both xanthine oxidase (XO) and xanthine dehydrogenase (XDH) activities of the enzyme xanthine oxidoreductase (XOR), with a markedly better efficiency for XDH activity.Scavenging power on radical anion superoxide (O2•¯) by different N. sativa extracts has been evaluated using chemiluminescence assay where two extracts, HxE and ChE, exhibited good scavenger activity, with IC50 of 0.18 µg/ml and 0.3 µg/ml, respectively. Reducing power (RP) of the different obtained extracts has been assessed by the FRAP assay. ChE and AcE showed the highest RP, which is proportional to the polyphenol content. The obtained data revealed that the antioxidant activity of Nigella sativa’s seeds resides in the oil fraction of HxE (inhibition of XO and XDH, and scavenging O2•¯) and in ChE and AcE fractions expressing the most important reducing power

Keywords

• Antioxidants, Reactive oxygen species (ROS), Nigella sativa, Reducing power (RP), Xanthine oxidoreductase (XOR)