Phytogenic molybdenum nanoparticles using Pterocarpus santalinus: characterisation, antioxidant, antimicrobial, seed priming and nitrogen fixation activities

This study reports the phytogenic synthesis and multifunctional evaluation of molybdenum oxide nanoparticles (MoONPs) using Pterocarpus santalinus leaf extract as a natural reducing and stabilising agent. The synthesised MoONPs exhibited a distinct surface plasmon resonance peak at 364 nm, confirming their formation. FE-SEM/EDAX revealed spherical, high-purity nanoparticles, while XRD confirmed an orthorhombic crystalline phase with an average crystallite size of 35.71 nm. FT-IR identified functional groups involved in capping and stabilisation. MoONPs demonstrated significant antioxidant activity (40.21% ABTS inhibition at 100 µg/mL), comparable to ascorbic acid and superior to the extract alone. They also exhibited strong antimicrobial activity against phytopathogenic bacteria (X. campestris, P. syringae, C. michiganensis, S. aureus) and fungi (A. niger, A. flavus), demonstrating notable antimicrobial activity compared to standard controls. As a seed-priming agent for Arachis hypogaea, MoONPs enhanced germination (up to 227.5%), vigour index (up to 379.4), and root/shoot elongation. MoONPs boosted nitrate reductase activity by 67%, increased chlorophyll content by 79%, and improved biomass accumulation and plant height. Collectively, these findings indicate that Pterocarpus santalinus-mediated MoONPs exhibit multifunctional properties with potential applications as nano-fertilizers and biocontrol agents in agriculture; however, further studies are required to evaluate their safety and environmental impact before practical implementation.