Effects of hydroalcoholic extract of Glycyrrhiza glabra and glycyrrhizic acid on promastigote and amastigote of Leishmania major (MRHO/IR/75/ER)

Background: Cutaneous leishmaniasis by different species of Leishmania. Pentavalen antimonials as a first line drug for treatment of cutaneous leishmaniasis have several limitations and side effects. Natural products are more considered due to their less toxicity and cost, more efficient, safety and readily available antileishmania agents. Objective: The aim of this study was to explore the effect of hydroalcoholic extract of Glycyrrhiza glabra (licorice) roots and its main component glycyrrhizic acid on promastigote and amastigote of L. major. Methods: Different dosages of hydroalcoholic extract of licorice root, glycyrrhizic acid and Glucantime with promastigote of L. major were incubated at 26 °C for 24 and 48 hours then the percentages of alive promastigotes were measured by MTT assay. The antiamastigote effects of these drugs was examined by microscopic counting of the number of amastigotes in macrophages 24 hours after treating the parasite infected macrophages with them. Promastigote and infected macrophages without any treatment was used as negative controls. Results: The IC50 values of hydroalcoholic extracts of licorice root, glycyrrhizic acid and Glucantime on promastigote of L. major was 1250 ± 0.018, 3000 ± 0.017 and 50 ± 0.043 μg/ml after 24 hours, and 1000 ± 0.016, 3000 ± 0.017 and 25 ± 0.009 μg/ml after 48 hours, respectively. The IC50 values of the licorice root extract, glycyrrhizic acid and Glucantime on amostigate was 500, 1000 and 25 μg/ml, respectively. Conclusion: Hydroalcoholic extract of licorice root and glycyrrhizic acid had cytotoxic effects on promastigotes and amastigotes of L. major.