Green synthesis and characterization of silver nanoparticles using heliotropium indicum l. leaves extract and antimicrobial activity

Silver is known for its antimicrobial effects and silver nanoparticles have become a promising synthetic strategy due to its antimicrobial potential. The study was carried out in Heliotropium indicum L. aqueous leaves extract for determining the antimicrobial activity of silver nanoparticles (AgNPs) against human skin pathogens with statistical tests at 1% level of significance. Characterization of AgNPs was carried out by UV-Vis Spectroscopy, X-ray Diffraction Spectroscopy (XRD) and Scanning Electron Microscopy (SEM). Antimicrobial activities of AgNPs was determined by agar well diffusion method and MIC was determined by resazurin-based turbidometric method. The UV spectroscopic analysis showed the highest absorbance peak at 420 nm. The particle size and structure was confirmed by SEM analysis and it was revealed that the formed particles were of different shapes but predominantly spherical with an average size of 77-98 nm with interparticle distance. The crystalline nature of the AgNPs was determined by X-ray diffraction patterns. The biosynthesized AgNPs exhibited excellent antibacterial activity against Pseudomonas aeruginosa (MTCC 4676) and antifungal activity against Candida albicans (MTCC 183). Kolmogorov-Smirnov and Shapiro-Wilks test, Levene’s test of homogeneity of variance and ANOVA were performed using SPSS software. The ANOVA test revealed that the zone of inhibition against P. aeruginosa, S. aureus, B. cereus, T. rubrum and C. albicans was significantly different among samples at 1% level of significance (p less than 0.01). The potent antimicrobial activity may justify the biomedical use of AgNPs as antimicrobial agents for controlling microbial infections.