Abstract

PALMA TOVAR, Camila Isabel et al. Fluorometric method for the identification of cytotoxic natural agents and its application in the evaluation of selective antiparasitic agents. Rev.Cs.Farm. y Bioq [online]. 2019, vol.7, n.1, pp.21-30. ISSN 2310-0265.

Abstract The Ministry of Health has infectious diseases as one of the research priorities, including leishmaniasis and American try-panosomiasis. The Faculty of Pharmaceuti-cal and Biochemical Sciences develops eval-uations of medicinal plant species used by the Tacana culture as a source of potential antiparasitic agents. Laboratories dedicated to the discovery of natural molecules with antiparasitic ac-tivity, have the challenge of developing pro-tocols that allow the detection of selective, effective and less toxic biomolecules than those available. Therefore, in vitro antipar-asitic evaluations (IC₅₀) should be accompa-nied by cytotoxicity evaluations (LD₅₀), in order to calculate a Selectivity Index (IS = LD₅₀ / IC₅₀) as a parameter of biological specificity. The cytotoxicity was measured on mac-rophage line (RAW 264.7, murine), cells en-gaged on intracellular parasites infections. The fluorometric protocol starts with an ini-tial population of 5x10⁴cells/mL, incubated at 37°C, in DMEM (Dulbecco's Modified Eagle's medium) for 96 hours with addition of resazurin (2mM) 3 hours, before final read-ings. Under these conditions the cytotoxicity of control drugs and 15 plant extracts, se-lected by their anti-kinetoplastid activity, was evaluated. Cosumailu extract was the most cytotoxic, Ejije bid'u was selective for T. cruzi, and Leishmania amazonensis, while Id'ene eidhue, was selective for L. amazonensis. Finally, the other 12 extracts were lit-tle selective or cytotoxic.

Keywords : Trypanosoma cruzi; Leishmania amazonensis; RAW 264.7 cells; Tacana culture; Resazurin Fluorometric Method; Selectivity Index.

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