Compounds with NO Inhibitory Effect from the Rattan Stems of Sinomenium acutum, a Kind of Chinese Folk Medicine for Treating Rheumatoid Arthritis

Three new alkaloids (1-3), one new diphenyl ether (4) and fifteen known alkaloids (5-19) were isolated from the rattan stems of Sinomenium acutum. Comprehensive analyses of HR-ESI-MS, 1D (1 H and 13 C), 2D-NMR (1 H-1 H COSY, HSQC, HMBC, NOESY), circular dichroism (CD), UV and IR revealed the structures and absolute configurations of these new compounds. The structures of other compounds were determined by comparison of their 1 H and 13 C-NMR data with previous literature reports. By measuring the amount of NO produced, the anti-inflammatory properties of the isolated compounds were studied. The results showed that compounds 4 and 5 had strong NO inhibitory activity.