Chemical constituents of Syzygium cerasiforme leaves and their nitric oxide inhibitory activity in LPS-activated RAW264.7 cells

Abstract

A phytochemical study of the methanolic extract of Syzygium cerasiforme leaves led to the isolation of seven compounds (1-7). Their chemical structures were identified as benzyl-6'-O-galloyl-β-D-glucopyranoside (1), 3-methoxy-4- hydroxyphenol 1-0-β-D-(6'-O-galloyl)-glucopyranoside (2), betulonic acid (3), 3-epi-betulinic acid (4), 7α-methoxy-stigmast-5-en-3β-ol (5), dihydrodehydrodi- coniferyl alcohol (6), and secoisolariciresinol (7), by HR-ESI-MS, 1D-and 2D NMR spectra, and by comparison with the previously published data. Compounds 1-7 exhibited NO production inhibitory activity in LPS-activated RAW264.7 cells with IC₅₀ values of 33.17, 25.51, 51.09, 54.17, 39.54, 6.98, and 58.12 µm, respectively, compared to that of the positive control compound, L-NMMA, which showed an IC₅₀ of 32.5 µm. This is the first report on these compounds from S. cerasiforme.