New glycosidic constituents from fruits of Lycium chinense and their antioxidant activities

摘要

Potential biologically active new constituents labd-3 beta, 9 beta-diol-3 alpha-D-glucopyranosyl-(2a -> 1b)-alpha-D-glucopyranosyl-(2b -> 1c)-alpha-D-glucopyranosyl-(2c -> 1d)-alpha-D-arabinofuranosy1-2d-p-hydroxybenzoate (1) and alpha-D-glucuronopyranosyl (2 -> 1')-alpha-D-glucuronopyranosyl (2' -> 1")-alpha-D-glucopyranosyl-2"-n-octadec-9"-enoate (2) along with beta-sitosterol-beta-D-glucoside were isolated from the fruits of Lycium chinense. Their chemical structures were elucidated using detailed spectroscopic studies. The structure assignments are based on two-dimensional (2D)-NMR techniques including COSY, HSQC, HMBC and NOESY experiments. Compounds 1 and 2 were evaluated for antioxidant activities with three assay protocols such as diphenylpicrylhydrazyl (DPPH) radical scavenging activity, reducing power and the phosphomolybdenum activity, compound 2 showed more potential as compared with 1. (C) 2013 Production and hosting by Elsevier B.V. on behalf of King Saud University.