Anti-HIV crotocascarin ω from Kenyan <i>Croton dichogamus</i>

An anti-HIV methanol-soluble fraction of a 1:1 CH2Cl2:CH3OH 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 IC50 value of 5.3 nM, and the compound was cytotoxic towards MT-4 cells presenting an IC50 value of 84 µM. In silico modelling showed that the anti-HIV activity for compound 1 could be through the HIV-1 protease inhibition.