Cashew Plant-Mediated Biosynthesis of Silver Nanoparticles and Evaluation of their Applications as Antimicrobial Additive for Consumer Care Products

This study reports the biogenic synthesis of silver nanoparticles (AgNPs) using aqueous extractobtained from Anacardium occidentale stem bark and evaluation of their antibacterial activities aswell as their potential applications as antimicrobial additives for detergent and toothpaste. Thebiosynthesized AgNPs were analyzed using UV–Vis spectroscopy, Fourier-transform infraredspectroscopy (FTIR), and scanning electron microscopy (SEM). The particles were dark brown incolour with maximum absorbance at wavelength 419 nm. They were mainly spherical in shapewith size ranges from 20 to 60 nm. The peaks of FTIR spectrum revealed that their formation wasfacilitated by protein molecules present in the extract. The AgNPs exhibited strong antibacterialproperty against pathogenic strains of Staphylococcus aureus, Escherichia coli and Pseudomonasaeruginosa. Furthermore, the incorporation of the AgNPs into a locally-made liquid detergent andtoothpaste led to complete inhibition of bacterial and fungal contaminants such as S. aureus, E.coli, P. aeruginosa, Aspergillus niger, and Aspergillus flavus. The results obtained herein thereforesuggest potential applications of the AgNPs in biomedical area and as antimicrobial additives inthe production of consumer care products like detergents and toothpastes. To the best of ourknowledge, this is the first reference to the use of biosynthesized AgNPs as antimicrobial additivesfor detergents and toothpastes. Keywords: Anacardium occidentale; Silver nanoparticles; Biosynthesis; Antimicrobial activity;Antimicrobial additive.