Abstract: Nitraria tangutorum Bohr. fruits were extracted using 95% ethanol, and then the extract was partitioned with petroleum ether, chloroform, ethyl acetate and n-butanol successively. The antioxidant activities of different fractions were evaluated by scavenging capability of ABTS+ and DPPH free radicals, and compared with the antioxidant activities of ascorbic acid (vitamin C) and tocopherol (vitamin E). Results indicated that ethyl acetate fraction (EAF) exhibited the highest antioxidant activity. EAF was further fractionated into 6 fractions by silica gel column chromatography. The antioxidant activities of EAFI and EAF-IV were higher than those of vitamin C and vitamin E. Therefore, N. tangutorum fruit extracts have excellent antioxidant activities, and have promising application prospects as a natural antioxidant.

Key words: Nitraria tangutorum Bohr. fruit, DPPH free radical, ABTS+ free radical, antioxidant activity, separation and purification