In vitro antileishmanial effects of Physalis angulata root extract on Leishmania infantum.

Objective: In the present study, we evaluated the effects of the aqueous extract of Physalis angulata root (AEPa) on Leishmania infantum proliferation, morphology, and the driving mechanism in leishmanicidal activity and modulatory action on macrophages.

Methods: L. infantum promastigotes were treated with 50 and 100 µg/mL AEPa for 72 h and then antipromastigote assay was performed by counts in a Newbauer chamber, morphological changes were analyzed by transmission electron microscopy and the mechanism of the leishmanicidal activity was detected. In addition, macrophages were infected with L. infantum and were used to evaluate anti-amastigote activity of AEPa and effects of AEPa on cytokine secretion after 72-hour treatment.

Results: Treatment with AEPa reduced the numbers of L. infantum promastigotes (50% inhibitory concentration (IC) = 65.9 μg/mL; selectivity index (SI) = 22.1) and amastigotes (IC = 37.9 μg/mL; SI = 38.5) compared with the untreated control. Amphotericin B reduced 100% of the promastigote numbers after 72 h of treatment (IC = 0.2 μg/mL). AEPa induced several morphological changes and increased the production of reactive oxygen species and apoptotic death in promastigotes after treating for 72 h. AEPa (100 μg/mL) promoted tumor necrosis factor-α secretion in macrophages infected with L. infantum after 72 h of treatment, but did not induce an increase in this cytokine in noninfected macrophages. In addition, AEPa showed no cytotoxic effect on J774-A1 cells (50% cytotoxic concentration >1000 μg/mL).

Conclusion: AEPa presented antileishmanial activity against the promastigotes and amastigotes of L. infantum without macrophage cytotoxicity; these results show that natural products such as P. angulata have leishmanicidal potential and in the future may be an alternative treatment for leishmaniasis.