Phenolic glycosides from Yua thomsonii

Phytochemical study of Yua thomsonii aerial parts led to the isolation of seven phenolic glycosides, including three new compounds, namely yuaphenosides A-C (1-3). The structural elucidation was confirmed by a detailed analysis of the 1D and 2D NMR and HR-ESI-QTOF mass spectra. Compounds 4-7 were isolated from Y. thomsonii for the first time. Among the isolated compounds, yuaphenoside A (1) and piceatannol-3 '-O-ss-D-glucopyranoside (6) exhibited significant inhibitory effect on LPS-induced NO production in RAW264.7 cells. Moderate effect was observed for yuaphenoside B (2), saccharumoside B (4), piceid (5), and piceatannol-4 '-O- ss-D-glucopyranoside (7); whereas weak activity was found for yuaphenoside C (3).