New Isopropyl Chromone and Flavanone Glucoside Compounds from the Leaves of Syzygium cerasiforme (Blume) Merr. & L.M.Perry and Their Inhibition of Nitric Oxide Production

Abstract

AbstractA new isopropyl chromone (1) and a new flavanone glucoside (2) together with eleven known compounds (3–13) were isolated from the leaves of Syzygium cerasiforme (Blume) Merr. & L.M.Perry. Their structures were elucidated as 5,7‐dihydroxy‐2‐isopropyl‐6,8‐dimethyl‐4H‐chromen‐4‐one (1), 5,7‐dihydroxyflavanone 7‐O‐β‐D‐(6′′‐O‐galloylglucopyranoside) (2), strobopinin (3), demethoxymatteucinol (4), pinocembrin‐7‐O‐β‐D‐glucopyranoside (5), (2S)‐hydroxynaringenin‐7‐O‐β‐D‐glucopyranoside (6), afzelin (7), quercetin (8), kaplanin (9), endoperoxide G3 (10), grasshopper (11), vomifoliol (12), litseagermacrane (13) by the analysis of HR‐ESI‐MS, NMR, and CD spectral data. Compounds 1, 2, 5, 6 and 10 inhibited NO production on LPS‐activated RAW264.7 cells with IC50 values of 12.28±1.15, 8.52±1.62, 7.68±0.87, 9.67±0.57, and 6.69±0.34 μM, respectively, while the IC50 values of the other compounds ranging from 33.38±0.78 to 86.51±2.98 μM, compared to that of the positive control, NG‐monomethyl‐L‐arginine acetate (L‐NMMA) with an IC50 value of 32.50±1.00 μM.