Synthesis of salidroside analogues and their ability of DPPH radical scavenging activity

Salidroside is a phenylpropanoid glycoside isolated from Rhodiolarosea L., a traditional Chinese medicinal plant, and has displayed a broad spectrum of pharmacological properties. In this paper, about 22 novel glycosides have been synthesized and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenge activity of each glycoside has been evaluated. 2-(3,4,5-Trihydroxyphenyl)ethyl beta-D-galactopyranoside and 3-(3,4,5-trihydroxyphenyl)propyl beta-D-glucopyranoside exhibit significant activity prior to salidroside and Vitamin C with EC50 values of 35.85 mu M and 36.71 mu M; respectively. The results indicate that the phenolic hydroxyl group of these compounds is important for radical scavenging activity and phenyl ring substitution by electron-donating substituents lead to increased antioxidant activity.