In vitro antileishmanial activity and apoptosis induction of Pleurotus ostreatus alcoholic extract on Leishmania major

Background and objectives: Leishmaniasis is caused by the genus Leishmania. Medications such as antimony compounds for the treatment of the disease are associated with limitations along with several side effects and disease recurrence; thus, evaluation of natural compounds with history of antimicrobial properties such as   Pleurotus ostreatus, is of a great importance. The purpose of this study was to evaluate the apoptotic and leishmanicidal effects of Pleurotus ostreatus alcoholic extract on Leishmania major promastigote in vitro. Methods: Different concentrations of Pleurotus ostreatus extract (50, 100, 150, 200 and 250 μg/mL) were tested at 6, 24, 48 and 72 h on Leishmania major (MRHO/IR/75/ER) promastigotes. The leishmanicidal effects were determined using MTT [3-(4,5-dimethyl thiazolyl- 2)-2,5-diphenyle tetrazolium bromide] assay. Also, apoptosis induction was measured by flow cytometry and DNA fragmentation analysis. Results:The MTT results showed that leishmanicidal effect of Pleurotus ostreatus extract was dependent to extract concentration in a way that the lowest number of live promastigotes was obtained after treatment with 200 μg/mL of extract preparation at 72 h. The IC50 of Pleurotus ostreatus extract was 160±2 μg/mL. Flow cytometric analysis showed that the extract could induce apoptosis in promastigotes at its IC50. Also, the result of gel electrophoresis showed that DNA fragmentation of treated promastigotes at the same concentration. Conclusion: The results indicated that Pleurotus ostreatus alcoholic extract have a strong toxic effect on cultivated Leishmania parasites. Based on these results in vivo studies using rodent models and human cutaneous leishmaniasis CL is recommended.