Antimalarial, antimycobacterial and antiproliferative activity of phenyl substituted mixed tetraoxanes

Mixed tetraoxanes of the 4 -phenyl-substituted cyclohexyl-spirotetraoxacyclohexyl-spirocholate series have been prepared and evaluated as possible antimalarials, antiproliferatives and antimycobacterials. The activity of the (4 R or S)-phenyl series against P. falciparum D6 and W2 strains was found to be at the level of artemisinin, with two compounds, the acid 4 and the amide 6, exhibiting encouraging anti-TB activity as well. Very promising in vitro results of the said tetraoxanes were obtained against solid tumours and, in some instances, the activity against a selected number of cell lines was higher than that of the antitumor drug paclitaxel.