Exploring the larvicidal and repellent potentials of silver nanoparticles greenly synthesized using three Congolese plant extracts against Anopheles gambiae along with molecular docking analysis

Chemical larvicides and repellents have long been used to combat Anopheles gambiae, the primary malaria vector. However, their prolonged application has raised significant concerns regarding environmental toxicity, human health risks, and the emergence of resistant mosquito populations. This study presents a sustainable alternative consisting of green-synthesized silver nanoparticles (AgNPs) derived from Lippia multiflora, Ocimum gratissimum, and Tetradenia riparia. These nanoparticles were characterized using several techniques, including UV–visible spectrophotometry, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FTIR) spectroscopy, revealing their spherical structure with diameters of 20–50 nm and stabilization by plant secondary metabolites. Aqueous suspensions of AgNPs derived from these three plants demonstrated dose-dependent larvicidal efficacy, achieving up to 95% mortality, while creams containing AgNPs from Lippia multiflora and Ocimum gratissimum exhibited an impressive 85% repellent efficiency. Molecular docking studies revealed that secondary metabolites used as capping agents enhanced larvicidal activity by inhibiting angiostensin converting enzyme of Anopheles gambiae (AnoACE2), further demonstrating the synergistic role of these metabolites in stabilising and boosting AgNPs efficacy. These findings highlight the potential of green-synthesized AgNPs as an eco-friendly and effective alternative to conventional chemical larvicides and repellents, addressing a pressing global need for sustainable mosquito control strategies. By leveraging the bioactivity of plant-derived compounds, this approach minimises environmental and health risks while offering high efficacy against malaria vectors. This research underscores the significant role of green nanotechnology in developing innovative solutions to vector control, paving the way for its integration into holistic malaria prevention programs and the fight against other mosquito-borne diseases.