Synthesis and Characterization of Silver Nanoparticles from &lt;I&gt;Ashyranthus aspera&lt;/I&gt; Extract for Antimicrobial Activity Studies

V Swetha,Samraj J Jenson,G Sabeena,G Annadurai,S Lavanya,E Pushpalaksmi

doi:10.4314/jasem.v24i7.6

Abstract

Development of biologically inspired experimental processes for the synthesis of nanoparticles is evolving into an important branch of nanotechnology. Plant-mediated synthesis of nanomaterials has been increasingly gaining popularity due to its eco-friendly nature and cost-effectiveness. In the present study, we were synthesized silver (Ag) nanoparticles using aqueous extracts of fresh leaves of Ashyranthus aspera medicinal plants as bio-reducing agents. UV-Vis spectrometer used to monitor the reduction of Ag ions and the formation of AgNPs in the medium. UV-Vis spectra and visual observation showed that the color of the fresh leaf extracts of Ashyranthus aspera turned into grayish-brown respectively, after treatment with Ag precursors. XRD and SEM have been used to investigate the morphology of prepared AgNPs. The peaks in the XRD pattern are associated with that of the Face-Centered-Cubic (FCC) form of metallic silver. TGA/DTA results associated with weight loss and exothermic reaction due to the desorption of chemisorbed water. FTIR was performed to identify the functional groups which form a layer covering AgNPs and stabilize the AgNPs in the medium. Moreover, silver nanoparticles using aqueous leaf extracts of Ashyranthus aspera were separately tested for their antibacterial activity against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Enterobacter). The results showed that the bacterial growth was inhibited by the extracts containing AgNPs Nanoparticles. The biosynthesized nanoparticle was prepared from Ashyranthus aspera leaf extracts exhibits potential applications as broad-spectrum antimicrobial agents Keywords: Ashyranthus aspera, Silver Nanoparticles, Plant extracts, Bacteria, Antibacterial activity.

Highlights

Development of biologically inspired experimental processes for the synthesis of nanoparticles is evolving into an important branch of nanotechnology
Preparation of Leaf Extract: Aqueous leave extracts were prepared by the following procedure: fresh leaves of Ashyranthus aspera were collected and washed with tap water at first, and the surface was washed under running water with distilled water until no impurities remained
Antibacterial activity of biosynthesized Ag NPs: The antibacterial activity of the biosynthesized silver nanoparticles against Gram-positive and negative bacteria species was done by agar well diffusion method

Summary

MATERIALS AND METHODS

Chemicals and Plant Material Collection: All the reagents purchased were of analytical grade and used without any further purification. Distilled water was used for preparing aqueous solutions all over the experiments. Preparation of Leaf Extract: Aqueous leave extracts were prepared by the following procedure: fresh leaves of Ashyranthus aspera were collected and washed with tap water at first, and the surface was washed under running water with distilled water until no impurities remained. The extract was stored in the refrigerator for further use to synthesize Ag nanoparticles from the AgNO3 precursor solution. The AgNO3 solutions were mixed with the aqueous extract of Ashyranthus aspera fresh leaves at a ratio of 1:1 (v/v) to a volume of 50mL in a flask. Antibacterial activity of biosynthesized Ag NPs: The antibacterial activity of the biosynthesized silver nanoparticles against Gram-positive and negative bacteria species was done by agar well diffusion method. Preliminary antibacterial activity of silver nanoparticles was evaluated using the agar well diffusion assay as described earlier (Li et al, 2004). The plates were incubated for 24h at 37°C, and diameters of zone of inhibition were recorded in millimeter (mm)

RESULT

Conclusion