Biosynthesis, Characterization and Antibacterial Effect of Phenolics-Coated Silver Nanoparticles Using Cassia javanica L

The development of phytomediated nanoparticles synthesis is receiving increasing attention due to ease of preparation, less chemical handling, and eco-friendly. In the present study, crystallization of silver ions to nanosized particles by aqueous leaves extract of Cassia javanica through bioreduction process was assessed. Strong plasmon resonance of silver nanoparticles was observed around 435 nm. UV–Vis spectroscopy, transmission electron microscope and Fourier transform infrared spectroscopy were performed to examine the formation of silver nanoparticles (AgNPs). The antibacterial activity of AgNPs was tested against four pathogenic Gram-negative bacteria. AgNPs showed strong antibacterial activity. The strongest activity was recorded on Pseudomonas aeruginosa with 34 mm zone of inhibition followed by Escherichia coli (28 mm), Enterobacter aerogenes (25 mm) and Salmonella typhimurium (23 mm) respectively. The Gram-negative bacteria were highly sensitive to AgNPs, whereas less sensitive to silver nitrate (AgNO 3 ) and C. javanica leaves extract. The AgNPs were also evaluated for the estimation of total phenolic content. It is concluded that leaves extracts can be used for the synthesis of AgNPs that is environmentally friendly and cost effective. These preparations can be used for various biotechnology and medical applications for controlling pathogenic bacteria.