Nitric Oxide Inhibitory Carbazole Alkaloids from the Folk Medicine Murraya tetramera C.C. Huang.

The phytochemical investigation of the leaves and stems of Murraya tetramera C.C. Huang, a traditional folk medicine used as an anti-inflammatory agent, yielded 19 simple carbazole alkaloids, two of which (1-ethoxy-3-methyl-9H-carbazol-2-ol (1) and 7-hydroxy-2,8-dimethoxy-6-methyl-9H-carbazole-1-carbaldehyde (2)) are new ones. The structures of the new compounds were determined by extensive spectroscopic analysis including NMR and HR-EI-MS experiments, as well as comparison with the reported data. Most of the isolates showed potent inhibitory effects on NO production in LPS-stimulated BV-2 microglial cells with IC50 values ranging from 5.1 to 15.1 µM.