International Science Community Association International Research Journal of Biological Sciences 15 3 2026 08 10 Biogenic Nanoparticles synthesized from Murraya koenigii (l.) Spreng. and their Broad-spectrum Antimicrobial activity 9 14 EN Auddya Deblina 1 Department of Botany, Raghunathpur College, Raghunathpur, Purulia, WB-723133, India and Department of Botany, Sidho Kanho Birsha University, Purulia, WB -723104, India Sinha Anjan Kumar 2 Department of Botany, Raghunathpur College, Raghunathpur, Purulia, WB-723133, India Puttaswamy Rajeshwari 1 Department of Botany Government Science College, Chitradurga, Karnataka, India > Research Paper 2026 6 18 2026 08 10 The extensive use of synthetic pesticides for controlling plant diseases has raised concerns regarding environmental safety and the development of resistant microbial populations, prompting the search for sustainable alternatives. In the present study, silver nanoparticles (AgNPs) were synthesized using the aqueous leaf extract of Murraya koenigii (L.) Spreng. through a green synthesis approach and evaluated for their antimicrobial activity against selected phytopathogenic bacteria and fungi. The formation of AgNPs was visually indicated by the transformation of the reaction mixture from pale yellow to dark brown and was confirmed by an absorption peak at approximately 430nm in the UV–Visible spectrum. Fourier Transform Infrared spectroscopy suggested the involvement of naturally occurring phytochemicals in the reduction and stabilization of nanoparticles, while Scanning Electron Microscopy revealed predominantly spherical particles ranging from 20 to 45nm in size. The antimicrobial potential of the synthesized AgNPs was investigated against Xanthomonas oryzae pv. oryzae, Xanthomonas campestris pv. vesicatoria, Xanthomonas campestris pv. campestris, Pseudomonas syringae, Aspergillus flavus and Fusarium verticillioides. The nanoparticles suppressed the growth of all tested pathogens in a concentration-dependent manner, with the highest antibacterial activity recorded against Xanthomonas oryzae pv. oryzae at 100µg mL⁻¹. Minimum inhibitory concentrations ranged from 25 to 75µg mL⁻¹, whereas minimum bactericidal/fungicidal concentrations varied between 50 and 150µg mL⁻¹. The results demonstrate that Murraya koenigii-mediated silver nanoparticles possess broad-spectrum antimicrobial activity and may serve as a promising eco-friendly alternative for managing plant diseases. These findings also reinforce the potential of plant-based nanotechnology as a sustainable approach for developing effective antimicrobial agents for agricultural applications. Copyright@ International Science Community Association