Structures of Clausamine-A, -B, -C, Three Novel Carbazole Alkaloids from Clausena anisata

Abstract

Three novel carbazole alkaloids, named clausamine-A (1), -B (2), and -C (3) were isolated from Clausena anisata (Rutaceae) collected in Thailand, and their structures were elucidated by means of spectroscopic analyses. All these novel carbazoles have 1-oxygenated 3, 4-disubstituted structures with a lactone moiety. This is the first report of the isolation of lactonic carbazole alkaloids from a natural source.