Three new phenolic glycosides from Rhus chinensis leaves

Three new phenolic glycosides, including 3-hydroxy-5-methylphenol 1-O-β-D-(6′-O-cinnamoyl)-glucopyranoside (1), 3-hydroxy-5-methylphenol 1-O-β-D-(6′-O-p-hydroxycinnamoyl)-glucopyranoside (2), 3-hydroxy-5-methylphenol 1-O-β-D-(6′-O-p-hydroxybenzoyl)-glucopyranoside (3), were isolated from the leaves of Rhus chinensis Mill, together with seven known compounds (4-10). Their structures were elucidated on the basis of extensive NMR spectral and high resolution mass spectrometry analysis. Among the isolated compounds, butein (4), quercetin (5), and ethyl gallate (6) exhibited moderate NO production in RAW264.7 cells induced by LPS with IC₅₀ values of 21.29 ± 0.54, 34.26 ± 2.09 and 42.59 ± 0.11 μM, compared with postive control L-NMMA (a nitric oxide synthase inhibitor, IC₅₀ 38.41 ± 0.32 μM).