BENZYL AND MEGASTIGMANE GLUCOSIDES FROM THE LEAVES OF ZANTHOXYLUM RHETSA (ROXB.) DC. AND THEIR INHIBITORY EFFECTS ON NITRIC OXIDE PRODUCTION

Abstract

Six metabolites (1–6) were successfully isolated from the leaves of Zanthoxylum rhetsa using a combination of chromatographic techniques. Their structures were elucidated as gnetifolin K (1), 4'-O-β-D-glucopyranosyl-(E)-4-hydroxy-3-methylbut-2-enyl benzoate (2), benzyl alcohol β-D-glucopyranoside (3), byzantionoside B (4), icariside B₅ (5), and (6S,9R)-roseoside (6) based on spectroscopic analyses, including HRESIMS, 1D and 2D NMR, and ECD data, supported by comparison with published literature. Compounds 1 and 2 are reported from the genus Zanthoxylum for the first time, whereas 4–6 are described for the first time from Z. rhetsa. The isolated compounds were evaluated for their inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages. Compounds 2 and 4 exhibited inhibitory activity with IC₅₀ values of 38.26 and 64.98 μM, respectively, compared with dexamethasone used as the positive control (IC₅₀ = 13.12 μM).