Six new alkaloid glycosides, Clausenasides A-F (1-6), along with two new quinoline alkaloids, Clausenasides G-H (7-8), and ten known compounds (9-18) were obtained from the stems of C. lansium. The structures of the new compounds were elucidated on the basis of their spectroscopic analysis, and the absolute configurations of 1, 2, 3 and 7 were confirmed by Mosher's method, CD and ECD spectra, respectively. Compounds 4, 6, 9, 17, and 18 showed moderate inhibitory effects on LPS-induced NO production in murine microglial BV2 cells (IC50 values < 10 mu M).