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. CI - (c) 2022 Wiley-VHCA AG, Zurich, Switzerland.