Clionasterol, a Triterpenoid from the Kenyan Marine Green Macroalga Halimeda macroloba

Abstract

The triterpenoid clionasterol (1), a 29 carbon structure compound was isolated from the less polar extract (20% EtOAc in hexanes) of the green alga Halimeda macroloba collected at Shimoni near Mombasa, Kenya. The structure and relative stereochemistry of this compound was elucidated by spectroscopic data, mainly NMR and mass spectrometry. This metabolite was inactive against DLD-1 cells on the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Further experiments on mosquito larvae and brine shrimp lethality confirmed this result.