A new xanthone from the Polygala tenuifolia Willd. of northern Shaanxi

Ten compounds were isolated and purified from ethanol extracts of dried roots bark of Polygala tenuifolia Willd. by various chromatography techniques such as silica gel and Sephadex LH-20. Their structures were identified by analysis of physicochemical properties and spectral data, and determined as β-sitosterol (1), tenuifolin (2), 6-methoxy coumarin (3), 7-phenyl-1-hydroxy-2, 3, 6-trimethoxyxanthone (4), 1, 8-dihydroxy-3, 4, 7-trimethoxyanthone (5), mangiferin (6), quercetin-3-O-β-D-glucoside (7), rutin (8), syringaldehyde (9), salicylicacid (10). Among them, compounds 3, 4 and 5 were isolated from the genus of Ploygala for the first time and compound 4 was a new xanthone. The acetylcholinesterase inhibitory activities of compounds 3, 4 and 5 were evaluated by Ellman colorimetric method, compounds 3 and 5 exhibited moderate inhibitory activity, compound 4 exhibited weak inhibitory activity.