INTRACELLULAR TOXOPLASMA GONDII ELIMINATION IN PRESENCE OF JcTI-I, A PROTEASE INHIBITOR FROM JATROPHA CURCAS SEED CAKE

Laís Pessanha de Carvalho*, Alexandra Martins dos Santos Soares, Helen Paula Silva da Costa, Ilka Maria Vasconcelos, José Tadeu Abreu de Oliveira and Edésio José Tenório de Melo

ABSTRACT

Toxoplasma gondii is the agent of toxoplasmosis, a widespread disease of medical and veterinary importance where the parasites infect all eukaryotic cells of vertebrate animals. There is no effective and low toxic treatment to eliminate the intracellular parasites, perpetuating the infection. The Jatropha species, including Jatropha curcas, acquired high economic importance as a source of high-quality biofuel and medicinal plant. Nevertheless, the anti-parasite activity of the Jatropha species has not been reported to date. In this study, the effects of a protease inhibitor from Jatropha curcas seed cake, named JcTI-I, on extra- and intracellular tachyzoites of T. gondii were assessed in vitro. Extracellular tachyzoites treated before invasion had morphological modifications but did not altered the establishment of infection. The incubation of infected host cells with 5, 10, 50, and 100 μM JcTI-I for 24 h decreased the intracellular parasite number (IC50 = 4.57 μM), without causing a significant reduction in the infected host cell population. Moreover, JcTI-I led ultrastructural alterations on intracellular tachyzoites as assessed by light and transmission electron microscopy. In summary, JcTI-I is a promising candidate for drug development to treat toxoplasmosis and other intracellular parasites.

Keywords: Physic nut; anti-Toxoplasma gondii action; serine protease inhibitor; antiprotozoal agent.