Alkaloids from Sri Lankan curry-leaf (Murraya koenigii) display melanogenesis inhibitory activity: structures of
Seikou Nakamura1, Souichi Nakashima, Yoshimi Oda
1Department of Pharmacognosy, Kyoto Pharmaceutical University, Misasagi, Kyoto 607-8412, Japan.
Abstract:
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.
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