Antifungal Indole Alkaloids from Winchia calophylla.

Ten indole alkaloids (1-10) were obtained from an antifungal extract of Winchia calophylla, of which two (2 and 4) were new. N(4)-Methyl-10-hydroxyl-desacetylakuammilin (2) was an akuammiline-type indole alkaloid. N(1)-Methyl-echitaminic acid (4) was an unusual zwitterion with a basic vincorine-type skeleton. This is the first report of 10 in W. calophylla. The structures of all of the compounds were determined based on spectroscopic data, and their bioactivities were assessed. Compound 1 showed potent activity against the plant pathogenic fungi of Penicillium italicum and Fusarium oxysporum f.sp cubens with IC₅₀ s of 10.4 and 11.5 µM, respectively, and 3 inhibited Rhizoctonia solani with an IC₅₀ of 11.7 µM. Compounds 2 and 4 showed weak cyto-toxicity against the human leukemic cell line HL-60 in vitro with IC₅₀s of 51.4 and 75.3 µM, respectively. Compounds 1 and 2 displayed weak activity against acetylcholinesterase with IC₅₀ s around 61.3 and 52.6 µM, respectively. [ABSTRACT FROM AUTHOR]