Steroidal saponins with anti-inflammatory activity from Tribulus terrestris L.

摘要

Objective:Tribulus terrestris L.(T.terrestris)is a highly valuable traditional Chinese medicine used to treat stroke,inflammation,pulmonary fibrosis,liver cancer,and urolithiasis.To identify the basic substance responsible for the anti-inflammatory effect of TST(total saponins of Tribulus),its chemical composition was systematically studied,and its effect of inhibiting nitric oxide generation and the expression of related inflammatory factors were determined.Methods:To separate chemical constituents from T.terrestris by column chromatography.Spectroscopic methods,including 1D and 2D nuclear magnetic resonance spectroscopy(NMR)and mass spectrometry(MS)techniques,were used to elucidate the isolated compounds.The anti-inflammatory activities of TST and several compounds were evaluated in vitro.Results:Fifteen steroidal saponins,including 9 furostanol steroidal saponins(1,2,3,4,5,6,7,8,and 15)and 6 isospirostanol steroidal saponins(9,10,11,12,13,and 14),were isolated from T.terrestris.TST significantly decreased the expression of tumor necrosis factor-a(TNF-a)and interleukin-6(IL-6)in RAW 264.7 cells stimulated by lipopolysaccharides.Compounds 13 and 15 evidently reduced TNF-a expression.Compounds 6,10,12,13,and 15 markedly reduced IL-6 expression.Conclusions:Compounds 1 was a novel furostanol steroidal saponin,named 26-O-b-D-glucopyranosyl-(25R)-5afurostan-12-carbonyl-20(22)-en-3b,26-diol-3-O-{b-D-xylopyranosyl-(1→2)-[b-D-xylopyranosyl-(1→3)]-b-D-glucopyranosyl-(1→4)-[a-L-rhamnopyranosyl-(1→2)]-b-D-galactopyranoside}.Compounds 2 was isolated from the family Zygophyllaceae for the first time,and 5 and 6 were isolated from the Tribulus genus.TST and compounds 6,10,12,13,and 15 exerts antiinflammatory activity.