Carbazole alkaloids from the stems of Clausena lansium.

Ten new carbazole alkaloids, claulansines A-J (1-10), and seven known analogues (11-17) were isolated from the stems of Clausena lansium. Their structures were established on the basis of extensive spectroscopic analyses, and their absolute configurations were determined by CD experiments and computational methods. Screening results indicated that compounds 1, 6, 8-10, 13, 14, and 17 showed selective neuroprotective effects at the concentration of 10 μM.