Parasite Killing of <i>Leishmania (V) braziliensis</i> by Standardized Propolis Extracts

Abstract

Treatments based on antimonials to cutaneous leishmaniasis (CL) entail a range of toxic side effects. Propolis, a natural compound widely used in traditional medical applications, exhibits a range of biological effects, including activity against infectious agents. The aim of this study was to test the potential leishmanicidal effects of different propolis extracts against <i>Leishmania (Viannia) braziliensis</i> promastigotes and intracellular amastigotes in vitro. Stationary-phase <i>L. (V) braziliensis</i> promastigotes were incubated with medium alone or treated with dry, alcoholic, or glycolic propolis extract (10, 50, or 100 <i>μ</i>g/mL) for 96 h. Our data showed that all extracts exhibited a dose-dependent effect on the viability of <i>L. (V) braziliensis</i> promastigotes, while controlling the parasite burden inside infected macrophages. Dry propolis extract significantly modified the inflammatory profile of murine macrophages by downmodulating TGF-<i>β</i> and IL-10 production, while upmodulating TNF-<i>α</i>. All three types of propolis extract were found to reduce nitric oxide and superoxide levels in activated <i>L</i>. <i>braziliensis</i>-infected macrophages. Altogether, our results showed that propolis extracts exhibited a leishmanicidal effect against both stages of <i>L. (V) braziliensis</i>. The low cell toxicity and efficient microbicidal effect of alcoholic or glycolic propolis extracts make them candidates to an additive treatment for cutaneous leishmaniasis.