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In this study, nine triterpene glycosides including seven previously undescribed compounds (1–7), were isolated from leaves of Cryptolepis buchananii R.Br. ex Roem. and Schult. using various chromatographic methods. The chemical structures of the compounds were elucidated to be 3-O-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyluncargenin C 28-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl ester (1), 3-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranosyluncargenin C 28-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl ester (2), 3-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranosyluncargenin C 28-O-β-d-glucopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl ester (3), 3-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranosylhederagenin 28-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl ester (4), 3-O-β-d-glucopyranosylarjunolic acid 28-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl ester (5), 3-O-β-d-glucopyranosyl-(1 → 2)-β- d-glucopyranosyl-6β,23-dihydroxyursolic acid 28-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl ester (6), 3-O-β-d-glucopyranosyl-6β,23-dihydroxyursolic acid 28-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl ester (7), asiatic acid 28-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl ester (8), and 3-O-β-d-glucopyranosylasiatic acid 28-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl ester (9), through infrared, high-resolution electrospray ionization mass spectrometry, one- and two-dimensional nuclear magnetic resonance spectral analyses. The isolates inhibited nitric oxide production in lipopolysaccharide-activated RAW 264.7 cells, with half-maximal inhibitory concentration (IC50) values of 18.8–58.5 µM, compared to the positive control compound, dexamethasone, which exhibited an IC50 of 14.1 µM. [ABSTRACT FROM AUTHOR]

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 µM, lower than that of the positive control compound, L-NMMA (IC50 = 33.8 µM). [ABSTRACT FROM AUTHOR]