Green synthesis of iron nanoparticles from cassia fistula linn leaf extract and its anti-bacterial activity

Nanotechnology is an emerging field in Biotechnology and it has vast applications in all fields. Biomolecules present in plant extracts can be used to reduce metal ions to nanoparticles in a single-step green synthesis process. This biogenic reduction of metal ion to base metal is quite rapid, readily conducted at room temperature, pressure and easily scaled up. Iron nanoparticles are reported to have magnetic, catalytic, optical, anti-inflammatory and antibacterial activity. In this study iron nanoparticles were successfully synthesized by reduction of ferric chloride solution using aqueous solution of Cassia fistula Linn leaf extract. The method was non-lethal, simple, ecoaccommodating and relatively inexpensive. The resulting iron nanoparticles were characterized by physical color changes, UV-Vis spectroscopy, Scanning Electron Microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy. The reaction mixture of aqueous ferric chloride and Cassia fistula Linn leaf extract displayed black color confirming the synthesis of iron nanoparticles. UV–Vis spectra showing an absorption band at 220nm characteristic of the iron nanoparticles in deed revealed the presence of nanoparticles. Images of the biosynthesized iron nanoparticles at different magnifications from SEM showed that the particles were spherical shaped and size of the nanoparticles ranged from 20-50 nm. Fourier transform infrared (FTIR) spectroscopy showed the contribution of O-H group, sulphate group, biopolymers, N-H group in primary amines and carboxylic groups in the synthesis procedure. The synthesized iron nanoparticles had antibacterial activity against pathogenic bacteria like Staphylococcus sp, Pseudomonas sp, Bacillus sp and Klebsiella sp by well diffusion method.