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

Abstract

This study reports the biogenic synthesis of silver nanoparticles (AgNPs) using aqueous extract obtained from Anacardium occidentale stem bark and evaluation of their antibacterial activities as well as their potential applications as antimicrobial additives for detergent and toothpaste. The biosynthesized AgNPs were analyzed using UV–Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The particles were dark brown in colour with maximum absorbance at wavelength 419 nm. They were mainly spherical in shape with size ranges from 20 to 60 nm. The peaks of FTIR spectrum revealed that their formation was facilitated by protein molecules present in the extract. The AgNPs exhibited strong antibacterial property against pathogenic strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Furthermore, the incorporation of the AgNPs into a locally-made liquid detergent and toothpaste 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 therefore suggest potential applications of the AgNPs in biomedical area and as antimicrobial additives in the production of consumer care products like detergents and toothpastes. To the best of our knowledge, this is the first reference to the use of biosynthesized AgNPs as antimicrobial additives for detergents and toothpastes.

Keywords: Anacardium occidentale; Silver nanoparticles; Biosynthesis; Antimicrobial activity; Antimicrobial additive.