Phytochemical and Antimicrobial Studies of Colloidal Silver Nanoparticles Mediated by Laportea aestuans Extract

This present report describes studies on the phytochemical screening and antimicrobial activity of colloidal silver nanoparticles (AgNPs) mediated by Laportea aestuans leaf extract in aqueous solution. Herein, AgNPs were facilely synthesized using the fresh leaf extract of Laportea aestuans in water. UV-Vis absorption spectrum of as-prepared AgNPs shows surface plasmon resonance (SPR) peak at ≈ 453 nm, suggesting successful formation of AgNPs. The X-ray diffraction pattern of the AgNPs were consistent with the Bragg’s reflections of AgNPs. Transmission electron microscope revealed that the prepared AgNPs are monodisperse, slightly non-aggregated and quasi-spherical in shapes. Phytochemical screenings of the leaves of L. aestuans shows presence of important bio-organic molecules that are responsible for the reduction, growth and stabilization of as-prepared AgNPs in aqueous solution. Bactericidal effects of the as-prepared biosynthesized AgNPs were carried out against pathogenic Gram-negative (Pseudomonas aeruginosa and Salmonella typhi) and Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacteria. Biosynthesized AgNPs showed enhanced antimicrobial activity against S. aureus (gram positive) and S. typhi (gram negative), compared to B. subtilis (gram positive) and P. aeruginosa (gram negative) at the tested concentrations. Impressive antimicrobial activity of L-Ag against the tested pathogens could be attributed to the synergistic effects of the biomolecules in the Laportea aestuans plants and silver nanostructures