Effect of Copaifera reticulata on amastigote forms of Leishmania (L.) amazonensis
At least 15–20 million persons in Latin America are infected with leishmaniasis, with 2 million new cases each year . Plants are a potential source of new antiprotozoal drugs . Copaiba oil has been used in folk medicine as an anti-inflammatory, antitumor, wound-cicatrisation, antinociceptive, and antimicrobial . In this study, the biological effects of oil resin from Copaifera reticulata against axenic amastigote forms of Leishmania amazonensis were evaluated. The antiproliferative effect was determined by direct counting of the cells in a Neubauer chamber. The survival index was determined, to evaluate the effect of the copaiba oil on intracellular amastigotes. Morphological and ultrastructural alterations of axenic amastigote forms treated with copaiba oil were analyzed by scanning and transmission electron microscopy. The antiproliferative assays showed a dose-dependent effect, with IC50/72h values for axenic amastigote of 15µg/ml. The internalisation index reflected a decrease of 47.7% when treated with 20µg/ml, compared to the control. Transmission electron microscopy showed the presence of myelin-like figures, appearance of autophagic structures, and formation of exocytic projections in the flagellar pocket. Axenic amastigotes of L. amazonensis treated with oil underwent remarkable morphological alterations, with rupture of the plasma membrane, as observed by scanning electron microscopy. Based on these results, copaiba oils appear to have potential as an alternative treatment for leishmaniasis.
Acknowledgements: This study was supported through grants from CNPq, FINEP, and PRONEX/Fundação Araucária.
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