Abstract: 【Objective】To separate, purify and identify the antioxidant compositions of black rice.【Method】Using total antioxidative capacity (TAC) as an activity monitoring parameter，different fractions of black rice antioxidative extracts were obtained with different polarities of solvents such as petroleum ether, chloroform, ethyl acetate and normal butyl alcohol. The main antioxidative components from the strongest antioxidative fractions were separated by using Sephadex LH-20 resin and the structures were analyzed by ultraviolet-vis, infra-red, ESI-MS, 1H-NMR and 13C-NMR spectrums.【Result】The water fraction and normal-butyl alcohol fraction of antioxidative extracts of black rice of had the strongest antioxidative capacities and their TACs reached 383 ku·g-1 and 392 ku·g-1, respectively. Four main antioxidative components were separated from the water fraction and their TACs reached 976 ku·g-1, 878 ku·g-1, 1 134 ku·g-1 and 1 087 ku·g-1, respectively. The spectroscopy analysis indicated that the 4 active components of the antioxidative extract of black rice were 4 anthocyanin compounds of malvidin, pelargonidin-3, 5-diglucoside, cyaniding-3-glucoside and cyaniding-3, 5-diglucoside. 【Conclusion】 It is concluded that the anthocyanin compounds are the most important substance basis for antioxidation.

Key words: Black rice, Antioxidative composition, Structure identification