Alkaloids from Sri Lankan curry-leaf (Murraya koenigii) display melanogenesis inhibitory activity: structures of karapinchamines A and B
- Bioorg Med Chem. 2013 Mar 1;21(5):1043-9. doi: 10.1016/j.bmc.2013.01.012.
- 1. Department of Pharmacognosy, Kyoto Pharmaceutical University, Misasagi, Kyoto 607-8412, Japan.
A methanolic extract and its ethyl acetate-soluble fraction from Sri Lankan curry-leaf, the leaves of Murraya koenigii, inhibited melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells. Two new Carbazole Alkaloids, karapinchamines A and B, were isolated from the ethyl acetate-soluble fraction together with 12 known Carbazole Alkaloids. The structures of karapinchamines A and B were determined by physicochemical analyses. The principal alkaloid constituents were found to display potent melanogenesis inhibitory activity. The structural requirements of the Carbazole Alkaloids for melanogenesis inhibitory activity were discussed.