Green synthesis of iron nanoparticles via Rhizoclonum riparium (Roth) Harvey: A promising nanotherapy against the promastigote forms of Leishmania donovani parasites

Visceral leishmaniasis, a life-threatening parasitic disease caused by Leishmania donovani (Roth) Harvey and transmitted by Phlebotomus sandflies, continues to pose a significant global health concern. Conventional therapies like amphotericin B and miltefosine are often limited by severe side effects and the emergence of resistance, necessitating the development of safer and more effective alternatives. In this study, iron-nanoparticles (INPs) were biosynthesized using green macroalga Rhizoclonium riparium using FeCl₃ (0.005 M) at pH 6, and the synthesized INPs were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, and dynamic light scattering (DLS), confirming their spindle-shaped morphology with average particle size of 82 nm. In vitro anti-leishmanial activity of the INPs was assessed against L. donovani using MTT assay, demonstrating significant efficacy with an IC₅₀ value of 43.36 µg/mL. These results suggest that algal-mediated INPs represent a promising eco-friendly nanotherapeutic strategy for the treatment of visceral leishmaniasis.