Synthesis, characterization and antimicrobial properties of green-synthesised silver nanoparticles from stem bark extract of Syzygium alternifolium (Wt.) Walp.

Today green synthesis of silver nanoparticles (SNPs) from plants is an utmost emerging filed in nanotechnology. In the present study, we have reported a green method for synthesis of SNPs from aqueous stem bark extract of Syzygium alternifolium, an endemic medicinal plant of South Eastern Ghats. These green-synthesised nanoparticles are characterised by colour change pattern, and the broad peak obtained at 448 nm with UV–Vis surface plasmon resonance studies confirm that the synthesised nanoparticles are SNPs. FT-IR spectroscopic studies confirm that phenols and proteins of stem bark extract is mainly responsible for capping and stabilisation of synthesised SNPs. Crystallographic studies from XRD indicates, the SNPs are crystalline in nature owing to 44 nm size. EDAX analysis shows 19.28 weight percentage of Ag metal in the sample indicates the purity of sample. AFM, SEM and TEM microscopic studies reveal that the nanoparticles are spherical in shape with sizes ranging from 4 to 48 nm. Antimicrobial studies of the synthesised SNPs on clinically isolated microbes showed very toxic effects. It indicates that stem bark extract of S. alternifolium is suitable for synthesising stable silver nanoparticles which act as excellent antimicrobial agents.