Antimalarial activity and nucleoside transport inhibitory activity of the triterpenic constituents of Cimicifuga spp.
The in vitro antimalarial activity against human malaria parasite (Plasmodium falciparum, FCR-3 strain) was examined using 59 triterpenoids obtained during studies on the triterpenic constituents of Cimicifuga spp. The 50% effective concentration values (EC50) of 25 active triterpenoids were 1.0-3.0 microM, and 19 of the compounds had a common 16, 23:23, 26:24, 25-triepoxy group in the side-chain moieties. Among the active triterpenoids, 9 also showed significant inhibition of nucleoside transport in mouse splenocytes. A relationship between the antimalarial activity and the inhibition of nucleoside transport involving these triterpenoids is discussed.