In vitro and in silico approaches manifest the anti-leishmanial activity of wild edible mushroom Amanita princeps

Abstract

Visceral Leishmaniasis, caused by Leishmania donovani, is the second most deadly parasitic disease, causing over 65,000 deaths annually. Synthetic drugs available in the market, to combat this disease, have numerous side effects. In this backdrop, we aim to find safer antileishmanial alternatives with minimal side effects from mushrooms, which harbour various secondary metabolites with promising efficacy. Robust screening of sixteen extracts from eight different wild mushrooms reveals that the hydroalcoholic extract of Amanita princeps has outstanding antileishmanial activity against Leishmania donovani. Metabolomic profiling of this lead extract identifies 50 bioactive mycocompounds and among them, 10 were selected for in-silico study against five major targets-arginase, spermidine synthase, ornithine decarboxylase, trypanothione reductase and SOD, crucial for thiol-redox balance in parasites in the polyamine synthesis pathway. Molecular docking analysis against our prioritised targets identified two mycompounds Ergosterol and Taraxacolide 1-O-b-D-glucopyranoside from Amanita princeps having the highest binding affinity of -15.8 and -11.8 kcal/mol respectively against the ornithine decarboxylase of polyamine synthesis pathway. However, MD simulations and free energy calculation using MM-GBSA analysis revealed the better stability of ergosterol with PASP receptors suggesting its promising role as an anti-leishmanial compound. Further results of in vitro arginase, SOD, and NO enzyme assays also corroborated with in-silico findings, reinforcing the anti-leishmanial efficacy of the Amanita princeps extract. Thus, both in silico and in vitro analyses suggest the efficacy of both Ergosterol and Taraxacolide 1-O-b-D-glucopyranoside compounds resourced from Amanita princeps as potent antileishmanial agents.

Keywords: Ergosterol; In silico docking; LC-MS; Molecular Dynamic Simulation; Taraxacolide 1-O-b-D-Glucopyranoside.