New potently bioactive alkaloids from Crinum erubescens

Antimalarial bioassay-guided fractionation of the swamp lily Crinum erubescens led to the isolation of four compounds with potent antiplasmodial activity. Compounds 1 and 2 were determined from their spectroscopic data to be the known pesticidal compound cripowellin A and the known pesticidal and antiproliferative compound cripowellin B. 1D and 2D-NMR techniques were used to determine the identities of 3 and 4 as the new compounds cripowellin C and D. A fifth compound was identified as the known alkaloid hippadine, which was inactive against Plasmodium falciparum. The antiplasmodial IC₅₀ values of compounds 1-4 were determined to be 30±2, 180±20, 26±2, and 260±20nM, respectively, and their antiproliferative IC₅₀ values against the A2780 human ovarian cancer cell line were 11.1±0.4, 16.4±0.1, 25±2, and 28±1nM.