New nitric oxide production inhibitors from Syzygium bullockii

Three undescribed triterpene glycosides syzybullosides A-C (1-3) along with fourteen known compounds were isolated from the leaves of Syzygium bullockii (Hance) Merr. & L.M. Perry, including six triterpene glycosides (1-6), four phenolics (7-9, 17), four megastigmanes (10-13), and three flavonoids (14-16). The structures of 1-17 were elucidated by extensive spectroscopic analysis, including IR, HR-ESI-MS, 1D and 2D NMR spectra. Compounds 1-10 and 12-17 inhibited nitric oxide (NO) production in lipopolysaccharide activated RAW264.7 cells with IC50 values ranging from 1.30 to 13.70 mu M, lower than that of the positive control compound, L-NMMA (IC50 = 33.8 mu M).

Automated summary

Three undescribed triterpene glycosides and fourteen known compounds were isolated from the leaves of Syzygium bullockii, including six triterpene glycosides, four phenolics, four megastigmanes, and three flavonoids. The structures were elucidated through spectroscopic analysis. Compounds 1-10 and 12-17 exhibited inhibitory activity against nitric oxide production in activated RAW264.7 cells, with IC50 values ranging from 1.30 to 13.70 μM, lower than that of the positive control compound L-NMMA (IC50 = 33.8 μM).