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Graphical abstractPromising antileishmanial properties were observed with Sargentodoxa cuneata mediated Ag and AuNPs. This study opens a platform for the synthesis new leishmanicidal agents AbstractLeishmaniasis remains one of the fatal diseases worldwide and the conventional antileishmanial therapies are associated with several drawbacks. Therefore, there is a need to develop new antileishmanial strategies. Biogenic silver and gold nanoparticles possess broad-spectrum antimicrobial activities and could be future alternative to current antimicrobial agents. In this report, we present a simple and green approach to synthesize silver and gold nanoparticles with efficient biological activities. Phytochemicals from Sargentodoxa cuneata were used to reduce and stabilize the silver and gold ions into metallic nanoparticles. The synthesized nanoparticles were characterized by UV-visible spectroscopy (surface plasmon resonance), X-ray diffraction analysis (crystallinity), High-resolution transmission electron microscopy (size and morphology), energy dispersive X-ray (elemental composition) and FTIR (surface functionalities). Under the optimized conditions, the synthesized silver nanoparticles were spherical in shape, small size (3-8 nm) and well dispersed. However, the gold nanoparticles were mostly hexagonal in shapes with approximate size from 15 to 30 nm. Promising antileishmanial activity was shown by silver and gold nanoparticles with an IC 50 value of 4.37 and 5.29 µg/mL respectively. Silver nanoparticles also exhibited significant antibacterial activity against Staphylococcus aureus (32 ± 3 mm), Pseudomonas araginosis (16 ± 2 mm), and Bacillus subtilis (18 ± 2 mm). The depicted biological activities of nanoparticles are not simply due to the capped silver and gold atoms but also to their surface macromolecules. Thus, the use of Sargentodoxa cuneata as reducing and capping agent will retain its biological activities even after the depletion of maintained silver and gold. The findings of this study indicate that, these nanoparticles could be an alternative, safe, and effective source of antileishmanial agents. 4 assay, and capillary electrophoresis 9-12 . These nanostructures upon cellular uptake behave as thermal scalpels to kill the infected cell 13,14 .Silver is a promising agent possessing broad spectrum antibacterial activity with minimum chance of bacterial resistance to it 15 . It has been published that silver ions interfere with bacterial DNA replication, disrupt cell membrane, inhibit critically important enzymes and damage bacteria by a process called respiratory burst mechanism 16-18 . Furthermore, silver and gold nanoparticles have the ability to produce reactive oxygen species (ROS), which play an important role in killing pathogenic microbes. It has been reported that leishmania parasites are highly sensitive to ROS 19 . In order to kill leishmania parasite by a treatment that involve reactive species, a continuous supply of these oxygen species can be ensured with the use of noble metal nanoparticles...

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