Neem-Mediated Silver Nanoparticles: Characterization and Biological Applications against Mosquito Larvae and Pathogenic Bacteria
Titilayo Oluwaseun AGUNBIADE
Department of Medical Biochemistry, Osun state University, Osogbo, Osun State, Nigeria.
Oluwadare Joel AGUNBIADE *
Department of Medical Biochemistry, Obafemi Awolowo University, PMB 13, Ile-Ife, Osun State, Nigeria.
Precious El-nathan KOLAWOLE
Department of Chemical Sciences, Oduduwa University, Ipetumodu, Osun State, Nigeria.
Kehinde Oluwatobi OKE
Department of Chemical Sciences, Oduduwa University, Ipetumodu, Osun State, Nigeria.
Adenike KUKU
Department of Biochemistry and Molecular Biology, Obafemi Awolowo University, PMB 13, Ile-Ife, Osun State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Introduction: Nanotechnology offers sustainable solutions for healthcare and environmental management. Silver nanoparticles (AgNPs) were green-synthesized using Azadirachta indica (Neem) leaf extract, a plant renowned for its broad pharmacological activities.
Aim: To biosynthesize neem-mediated AgNPs, characterize them physicochemically, and evaluate their larvicidal and antibacterial potency.
Materials and Methods: Aqueous neem leaf extract was mixed with AgNO₃; formation was tracked by colour change and UV–Vis spectroscopy (458–459 nm). FTIR identified functional groups, SEM measured morphology/size, and standard bioassays determined larvicidal activity against Culex quinquefasciatus larvae and antibacterial activity against selected pathogens.
Results: UV–Vis confirmed AgNP formation; FTIR showed hydroxyl, carbonyl and amine groups acting as reducing/stabilizing agents. SEM revealed 20–50 nm predominantly spherical particles. Probit analysis gave 24-h LC₅₀ values of 0.0279 mg L⁻¹ (AgNPs) versus 0.1985 mg L⁻¹ (neem extract). Agar-well diffusion assays showed larger inhibition zones for AgNPs than for extract, strongest against Staphylococcus aureus.
Conclusion: Neem-mediated AgNPs were successfully synthesized and characterized, showing strong larvicidal and antibacterial activities. These results highlight their potential as eco-friendly agents for vector control and antimicrobial use. Further in vivo and environmental safety studies are needed to confirm their applicability.
Keywords: Green synthesis, silver nanoparticles, Azadirachta indica, Culex quinquefasciatus, larvicidal activity, antibacterial activity