Studies on the chemical constituents of Pachysandra terminalis and their antioxidant activity

Objective:To study the chemical constituents from Pachysandra terminalis and their antioxidant activity.Methods:Chemical constituents were isolated by repeated column chromatography(silica gel,Toyopearl HW-40C and preparative HPLC).The structures of isolated compounds were elucidated on the basis of spectral data analysis.DPPH method was used to evaluate the free radical scavenging activity of the isolated compounds.Results:Six compounds were isolated and their structures were identified as follow:2-Phenylethyl-β-D-glucopyranoside(1),(+)Pinoresinol-4'-O-β-D-glucopyranoside(2),Pinoresinol(3),cis-Syringin(4),4-hydroxy-4-(3-oxo-l-butenyl)-3,5,5-trimethylcyclohex-2-en-l-one(5),3α-hydroxy-5,6-epoxy-7-megastigmen-9-one(6).Compounds 2,4,5 showed obviously antioxidant activity,their DPPH free radical scavenging rates were 82.50%,87.36%,and 84.56% on the concentration of 50 μmol/L,respectively.Conclusion:Compounds 1~6 are isolated from this genus for the first time.Compounds 2,4,and 5 showed significant antioxidant activities.