Mosquito larvicidal and antimicrobial activity of synthesized nano-crystalline silver particles using leaves and green berry extract of Solanum nigrum L. (Solanaceae: Solanales)

Abstract

Silver nanoparticles (AgNPs) that are synthesized by using aqueous extracts of Solanum nigrum L., is a simple, non-toxic and ecofriendly green material. The present study is based on assessments of the larvicidal and antimicrobial activities of the synthesized AgNPs from fresh leaves, dry leaves and green berries of S. nigrum against larvae of Culex quinquefasciatus and Anopheles stephensi and four human pathogenic and five fish pathogenic bacteria respectively. The synthesized nanoparticles are characterized with UV-vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscope (TEM) analysis. The nanoparticles are spherical to polyhedral in shape with size of 50-100nm (average size of 56.6nm). In larvicidal bioassay with synthesized AgNPs, highest mortality are observed at 10ppm against An. stephensi with LC50 values of 1.33, 1.59, 1.56ppm and LC90 values of 3.97, 7.31, 4.76ppm for dry leaves, fresh leaves and berries respectively. Antibacterial activity test reveals better results against fish pathogenic bacteria than human pathogenic bacteria. Non target organism like Toxorhynchites larvae (mosquito predator), Diplonychus annulatum (predatory water-bug) and Chironomus circumdatus larvae (chironomid) are also exposed to respective lethal concentrations (to mosquito larvae) of dry nanoparticles and no abnormality in the non target organisms are recorded. These results suggest that the synthesized AgNPs of S. nigrum have the potential to be used as an ideal eco-friendly compound for the control of the mosquito larvae and harmful bacteria.

Keywords: Antimicrobial activity; Larvicidal activity; Non target; Silver nanoparticle; Solanum nigrum.