Ecofriendly Synthesis Of Silver Nanoparticles Using Aqueous Leaf Extracts of Hemigraphis Colorata (Blume) Hallier f. And Their Antibacterial Activity

The efficient biosynthesis of silver nanoparticles (AgNps) using the leaf extract of Hemigraphis colorata, has been studied and their antibacterial efficacy are evaluated. The plant taken under study is an excellent wound healing plant used to cure anaemia, ulcers and inflammations. The green synthesized silver nanoparticles have been characterized using UV-Visble (UV-Vis) spectrophotometry, X-ray diffraction (XRD), Fourier transform infra-red (FTIR), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). SEM and TEM determine the polygonal nature of the AgNPs with average diameter ranging from 20-50 nm.XRD analysis showed the three strong Bragg reflections at 37.8º, 45.8º and 64.19º that corresponds to the planes (111), (200) and (220) respectively, which is the crystal lattice of silver. Fourier transform infrared spectrometer (FTIR) analysis was carried out to determine the nature of capping agent in the extract. UV-Visible (Vis) spectrophotometer indicates Surface plasmon resonance (SPR) peak was at around 440nm,characteristic of noble metal silver. The biosynthesized AgNPs obtained showed significant antibacterial activities against Bacillus sp., Staphylococcus aureus, Enterococcus sp., Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Moraxella sp. and Serratia plymuthica. The highest antibacterial activity of AgNPs synthesized was found against Pseudomonas aeruginosa (15mm). Thus the study concludes that the biologically synthesized nanoparticles could be of immense use in the medical field for their efficient antimicrobial activity.