Assessment of the Antiprotozoal Activity of <i>Galphimia </i><i>g</i><i>lauca </i>and the Isolation of New Nor-secofriedelanes and Nor-friedelanes

Four new terpenoids, comprising three nor-secofriedelanes (1-3) and one nor-friedelane (4), were isolated from Galphimia glauca, together with the known flavonol quercetin and the sterols stigmasterol and sitosterol 3-O-β-D-glucoside. The structure elucidation of the new isolates was conducted by 1D and 2D NMR techniques. Compounds 1-4 were given the trivial names galphin A, galphin B, galphin C, and galphimidin, respectively. All isolates were tested for in vitro antiprotozoal and cytotoxic activities. Quercetin was the only substance isolated that showed any antiprotozoal activity, and this was weak; the IC50 values were 14 μM against Plasmodium falciparum K1, 13.2 μM against Trypanosoma brucei brucei, and 63.8 μM against Leishmania donovani. Quercetin was found to be inactive against KB cells (IC50 = 295.8 μM).