Action of a pentacyclic triterpenoid, maslinic acid, against Toxoplasma gondii.

The action of maslinic acid (2alpha,3beta-dihydroxyolean-12-en-28-oic acid) (1), a pentacyclic derivative present in the pressed fruits of the olive (Olea europaea), has been studied against the tachyzoites of Toxoplasma gondii. The capability of tachyzoites to infect Vero cells treated with 1 was affected. The LD(50) values were 58.2 muM for the isolated tachyzoites and 236 muM for the noninfected Vero cells. Zymograms of the T. gondii proteases incubated with 1 showed a dosage-dependent inhibition of some of the proteases. The parasites treated with 1 showed gliding motility and ultrastructural alterations. The present findings suggest that protease activity of the parasite required for cell invasion is the action target for maslinic acid (1).