Green Synthesis, Characterization, and Antileishmanial Activity of the Silver Nanoparticles Alone and Along with Meglumine Antimoniate against Leishmania major Infection

The most commonly available drugs for leishmaniasis are pentavalent antimony compounds; whereas the recent studies showed various complications and limitations of these drugs. We aimed to green synthesized silver nanoparticles (AgNPs) and study the promising antileishmanial and synergic effects of green synthesized silver nanoparticles alone and combined with glucantime.

The precipitation technique was used to drop silver ions via an extract of Astragalus spinosus to AgNPs at Department of Biological Sciences, Faculty of Science and Humanities, Shaqra University, Saudi Arabia in 2022. Then, its anti-amastigotes, caspase-3-like activity, triggering the nitric oxide (NO) as well as its cytotoxicity effects on macrophage cells as well as effects on leishmaniasis in BALB/c mice infected by L. major were measured.

The size of the AgNPs were ranging from 30-40 nm. The IC50 value for AgNPs, AgNPs+ meglumine antimoniate (MA), and MA was 59.3, 18.6, and 51.2 μg/mL, respectively. The determined FIC value for AgNPs and MA was found to be 0.31 and 0.36, respectively; demonstrating the synergistic potency of AgNPs when combined with MA. The diameter of CL lesions treated with various doses of AgNPs and AgNPs+MA notably (p<0.001) decreased. AgNPs, particularly at the concentrations of ½ IC50 and IC50, considerably triggered the caspase-3 activation. The calculated CC50 of AgNPs and MA was 612.5 and 789.8 μg/mL, respectively. Green synthesized AgNPs, especially in combination with MA had synergic antileishmanial effects and displayed a promising drug candidate for treating L. major CL.

We found satisfactory findings in the parasite reduction in both in vitro and animal models. Still, more studies are expected to explain the precise action mechanisms of AgNPs and their efficacy in humans.