Triterpenoids with rare carbon skeletons from Salvia hydrangea: antiprotozoal activity and absolute configurations.

Salvadione C (1) and perovskone B (2), two new triterpenoids with rare carbon skeletons, were isolated from an antiplasmodial n-hexane extract of Salvia hydrangea. The absolute configuration was determined by comparison of experimental and calculated electronic circular dichroism (ECD) spectra. In vitro activity against Plasmodium falciparum K1 strain, Trypanosoma brucei rhodesiense STIB 900 strain, and cytotoxicity in rat myoblast (L6) cells were determined. Compounds 1 and 2 showed in vitro antiplasmodial activity, with IC50 values of 1.43 and 0.18 μM and selectivity indices (SI) of 86.2 and 69.6, respectively. IC50 values against T. brucei rhodesiense were found to be 4.33 and 15.92 μM, respectively.