In vitro antiprotozoal activity of triterpenoid constituents of Kleinia odora growing in Saudi Arabia.

Two lupane and four ursane triterpenes, namely epilupeol (1), lupeol acetate (2), ursolic acid (3), brein (4), 3β 11α-dihydroxy urs-12-ene (5) and ursolic acid lactone (6) were isolated from aerial parts of Kleinia odora and identified. Compounds 1 and 3-6 were isolated for the first time from K. odora. The triterpene constituents were investigated for antiprotozoal potential against erythrocytic schizonts of Plasmodium falciparum, intracellular amastigotes of Leishmania infantum and Trypanosoma cruzi and free trypomastigotes of T. brucei. Cytotoxicity was determined against MRC-5 fibroblasts to assess selectivity. The ursane triterpenes were found to be active against more than one type of the tested parasites, with the exception of compound 6. This is also the first report on the occurrence of ursane type triterpenes in the genus Kleinia and their antiprotozoal potential against P. falciparum, L. infantum, T. cruzi, and T. brucei.