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 A 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‐4 H ‐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 ), (2 S )‐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 IC 50 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 IC 50 values of the other compounds ranging from 33.38±0.78 to 86.51±2.98 μM, compared to that of the positive control, N G ‐monomethyl‐L‐arginine acetate (L‐NMMA) with an IC 50 value of 32.50±1.00 μM.