Anti-HIV crotocascarin ω from Kenyan Croton dichogamus .

An anti-HIV methanol-soluble fraction of a 1:1 CH 2 Cl 2 :CH 3 OH extract of twigs of a Kenyan Croton dichogamus yielded seven compounds, the new crotocascarin ω ( 1 ), the known β-oplopanone ( 2 ), dihydroconiferyl acetate ( 3 ), 3'(4''-hydroxyphenyl)-propyl benzoate ( 4 ), lupeol, sitosterol and stigmasterol. Crotocascarin ω (90%) inhibited HIV-1 replication with an IC 50 value of 5.3 nM, and the compound was cytotoxic towards MT-4 cells presenting an IC 50 value of 84 µM. In silico modelling showed that the anti-HIV activity for compound 1 could be through the HIV-1 protease inhibition.