Chemical constituents from the stems of Gymnema sylvestre

AimTo study the chemical constituents of stems of Gymnema sylvestre (Retz.) Schult.MethodsChromatographic techniques using silica gel, C18 reversed phase silica gel, and prep-HPLC were used. The structures were elucidated on the basis of MS and spectroscopic analysis (1D and 2D NMR), as well as chemical methods.ResultsSeven compounds were isolated and their structures were elucidated as conduritol A (1), stigmasterol (2), lupeol (3), stigmasterol-3-O-β-D-glucoside (4), the sodium salt of 22α-hydroxy-longispinogenin-3-O-β-D-glucopyranosyl-(1→3)-β-D-glu-curono-pyranosyl-28-O-α-L-rhamnopyranoside (5), oleanolic acid-3-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (6), and the sodium salt of 22α-hydroxy-longispinogenin 3-O-β-D-glucuronopyranosyl-28-O-α-L-rhamnopyranoside (7). The inhibition activities of compounds 1, 5−7 on non-enzymatic glycation of protein in vitro were evaluated.ConclusionCompound 7 is a new triterpenoid saponin. It was shown that compounds 1, 5−7 have weak inhibition activities for non-enzymatic glycation of protein in vitro.