Strychnovanosides A - C, Three New Lignan Glycosides from Strychnos vanprukii

Abstract

Phytochemical study of the methanolic extract of the stems and leaves of Strychnos vanprukii led to the isolation of three new (1-3) and four known (4-7) compounds. Their chemical structures were elucidated to be (+)-lyoniresinol 3 α-O- β-D-allopyranoside (1), (-)-lyoniresinol 3 α-O- β-D-allopyranoside (2), 2 α-[(3,5-dimethoxy-4-hydroxy)-benzoyl]-(-)-lyoniresinol-3 α-O- β-D-glucopyranoside (3), (+)-lyoniresinol 3 α-O- β-D-glucopyranoside (4), (-)-lyoniresinol 3 α-O- β-D-glucopyranoside (5), palicoside (6), and rutin (7) by means of detailed HR-ESI-MS, 1D and 2D NMR spectroscopic analysis. In addition, the absolute configurations of 1–3 were determined by experimental Circular Dichroism (CD) spectra. This is the first report of compounds 5 and 7 from S. vanprukii. Compounds 1 - 7 showed inhibitory effects on NO production in LPS stimulated RAW 264.7 cells with IC50 values of 58.50 ± 2.30, 67.70 ± 2.23, 54.44 ± 1.26, 71.58 ± 3.59, 74.47 ± 2.61, 83.62 ± 2.25, and 47.57 ± 4.01 µM, respectively, compared to a value of 43.24 ± 2.41 µM for the positive control compound, NG-monomethyl-L-arginine (L-NMMA).