Author : R.Bhuvaneswari, R.John Xavier and M.Arumugam

Objective: To investigate the antioxidant and antibacterial potential of green synthesized silver nanoparticles (AgNPs) using aqueous leaf extracts of Andrographisechioides (A.echioides).
Methods: Green nanoparticle was synthesized using A.echioides leaf extract. The synthesized AgNPs was characterized by Ultraviolet visible (UV-vis) spectroscopy, X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and Fourier transforms infrared spectroscopy (FTIR). The antioxidant activity was assed by DPPH free radical assay and the antibacterial activity was performed using disc diffusion method against B.subtilis, P.aeruginosa and S.aureus.
Results: Biosynthesis of AgNPs was determined by UV-vis spectrum that as intense Surface Plasmon Resonance (SPR) band at 440nm. AgNPs showed the XRD peaks at 2θ values of 27.44, 35.90, 37.20, 51.23 and 71.10º were identified with (311), (100), (101), (104) and (006) planes reflection values respectively. The FTIR spectrum of AgNPs exhibited prominent peaks located at 3255, 2930, 1604, 1390 and 1120 cm-1. The peaks were corresponding to the O-H stretching (alcohols and phenols groups), C-H stretching (alkane group), N-H bending (1°amines group), C-H stretching (alkanes and alkyl groups) and C-O stretching (alcohols, carboxylic acids, esters and ethers groups) vibrations respectively. FESEM analysis illustrated the shape in poly-dispersed spherical and size ranged from 17 to 27nm. DPPH free radical scavenging expressed highest percentage of antioxidant activity. The maximum antibacterial activity was noted in P.aeruginosa was 1.9cm of inhibition zone followed by S.aureus and B.subtilis (1.2 and 1cm).
Conclusion: The green synthesis of AgNPs using plant extract of A.echioides expressed its antioxidant against DPPH and antibacterial activity against P.aeruginosa; S.aureus; B.subtilis respectively.

Keywords: Andrographisechioides, Silver nanoparticles, Antioxidants, Antibacterial Activity, Surface Plasmon Resonance

Article published in International Journal of Current Engineering and Technology, Vol.5, No.4 (Aug-2015)