The reaction of hydroxyl radical with 1 phenylpropanoid glycoside (PPG), cistanoside C, and its 3 derivatives: I-O-β-D-2-(p-hydroxyphenyl)-ethanyl-glucose, 6-O-( E)-feruloyl-glucose and 6-O-( E)-p-hydroxy-cinnamoyl-g...The reaction of hydroxyl radical with 1 phenylpropanoid glycoside (PPG), cistanoside C, and its 3 derivatives: I-O-β-D-2-(p-hydroxyphenyl)-ethanyl-glucose, 6-O-( E)-feruloyl-glucose and 6-O-( E)-p-hydroxy-cinnamoyl-glucose isolated from folk medicinal herbs was investigated by pulse radiolysis technique respectively. The reaction rate constants were determined by analysis of built-up trace of absorption at λmax of specific transient absorption spectra of PPG and its derivatives upon attacking ·OH. All four compounds react with ?OH at close to diffusion controlled rate (1. 03 x 109-19.139X 109L·mol-1·s-1), suggesting that they are effective ?OH scavengers. The results demonstrated that the numbers of phenolic hydroxyl groups of PPG and its derivatives are directly related to their scavenging activities. By comparing the reaction rates of ·OH with l-O-β-D-2-(p-hydroxyphenyl)-ethanyl-glucose, 6-O-(E)-feruloyl-glucose or 6-O-(E)-p-hydroxy-cinnomoyl-glucose, it is evident that the phenylethyl group is more important than phenylacryloyl group for scavenging ?OH.展开更多
基金Project supported partly by the National Natural Science Foundation of Chinathe Doctoral Programme of the Minister of Education of China the China Postdoctoral Sciences Foundationthe Laboratory of Radiation Chemistry, Chinese Academy of Sciences.
文摘The reaction of hydroxyl radical with 1 phenylpropanoid glycoside (PPG), cistanoside C, and its 3 derivatives: I-O-β-D-2-(p-hydroxyphenyl)-ethanyl-glucose, 6-O-( E)-feruloyl-glucose and 6-O-( E)-p-hydroxy-cinnamoyl-glucose isolated from folk medicinal herbs was investigated by pulse radiolysis technique respectively. The reaction rate constants were determined by analysis of built-up trace of absorption at λmax of specific transient absorption spectra of PPG and its derivatives upon attacking ·OH. All four compounds react with ?OH at close to diffusion controlled rate (1. 03 x 109-19.139X 109L·mol-1·s-1), suggesting that they are effective ?OH scavengers. The results demonstrated that the numbers of phenolic hydroxyl groups of PPG and its derivatives are directly related to their scavenging activities. By comparing the reaction rates of ·OH with l-O-β-D-2-(p-hydroxyphenyl)-ethanyl-glucose, 6-O-(E)-feruloyl-glucose or 6-O-(E)-p-hydroxy-cinnomoyl-glucose, it is evident that the phenylethyl group is more important than phenylacryloyl group for scavenging ?OH.
