In vitro synthesis of antimicrobial silver nanoparticles by mangroves, saltmarshes and plants of coastal origin

Abstract

A total of 13 leaf extracts of coastal plants were used for the synthesis of silver nanoparticles and to test the antimicrobial potential of nanoparticles. The highest amount of nanoparticles was obtained by Sesuvium portulacastrum followed by Prosopis chilensis, Hibiscus rosasinensis and Clerodendrum inerme. The synthesised nanoparticles were spherical with variable size ranging from 5 to 20 nm, as evident by transmission electron microscopy. The synthesis of silver nanoparticles was confirmed with X-ray diffraction spectrum. Fourier transform infrared spectroscopy identified the presence of amide I, II and III, aromatic rings, geminal methyls and ether linkages indicating the presence of biomolecules responsible for stabilisation of the silver nanoparticles. Protein bands with molecular weight in a range of 35 to 100 kDa were detected. The nanoparticles inhibited clinical strains of bacteria and fungi with more distinct antifungal activity, which was enhanced when polyvinyl alcohol was added as a stabilising agent.