Free radical scavenging capacities of isoflavonoid glycosides isolated from Pueraria Radix

YANG Hua1,2,HAN Kun1,WAN Xiao-chun1,FANG Cong-bing 1,3 (1.Key Laboratory of Tea & Medicinal Plants and Product Safety,Ministry of Agriculture,Anhui Agricultural University,Hefei 230036; 2.School of Science,Anhui Agricultural University,Hefei 230036;3.School of Horticulture,Anhui Agricultural University,Hefei 230036)

isoflavonoid glycoside;isolation and purification;free radical scavenging capacity;Pueraria lobata(Willd) Ohwi.

Crude total isoflavonoids extracted from Pueraria Radix were partitioned by different organic solvents,then isolated and purified by several column chromatographic techniques and four isoflavonoid gly-cosides were obtained.On basis of the NMR and ESI-MS spectra,these four compounds can be identified as pu-erarin,daidzin,ononin,and genistin,respectively.Using an organic free radical system of 1,1-diphenyl-2-picrylhydrazyl(DPPH·) and an inorganic free radical system of superoxide anion free radical,the free radical scavenging capacities and antioxidant activities of these four isoflavonoid glycosides were examined in vitro.The results showed that all the four isoflavonoid glycosides were discovered to possess the scavenging capacities of the DPPH·free radical and superoxide anion radical.Meanwhile,there was a significantly positive correlation between the two free radical scavenging capacities and the treated concentrations of the four isoflavonoid gly-cosides.Genistin showed the highest DPPH·free radical scavenging capacity,followed by daidzin and puerarin,and ononin was the lowest among them.However,the superoxide anion free radical scavenging capacities of the four isoflavonoid glycosides were different from the former.Puerarin was discovered to be the strongest among them,followed by daidzin,genistin and ononin.