BACTERIOSTATIC ACTIVITIES OF ANTIOXIDANT SILVER NANOPARTICLES PREPARED FROM LEAVES OF AZADIRACHTA INDICA AND PSIDIUM GUAJAVA

Ishita Banik, Moytri Som, Sanchita Bhattacharjee, Sauryya Bhattacharyya* and Chandan Rai

ABSTRACT

Silver nanoparticles, developed from leaf of Azadirachta indica and Psidium guajava were examined for their antioxidant and antimicrobial properties. Among the five standard antioxidant assay protocols (viz. ABTS radical decolorization assay, DPPH radical decolorization assay, assay for total phenolis content, FRAP assay and hydroxyl radical scavenging assay) used in the present study, nanoparticles showed equivalent antioxidant activities with the aqueous leaf extracts. A likely chelation of the less polar biomolecules with Ag+ ion during nanoparticle formation was also indicated. Nanoparticle formation also improved the bacteriostatic properties in terms of zone of inhibition against all the five bacteria (viz. Escherichia coli, Klebsiella aerogens, Staphylococcus aureus, Salmonella typhi and Bacillus cereus) tested in the study. Improvement in bacteriostatic activities of the nanoparticles against the above mentioned microorganisms clearly indicated potential use of the nanoparticles against food borne bacteria for application in favor of humans.

Keywords: Antioxidant, Bacteriostatic, Nanoparticles, Azadirachta indica, Psidium guajava.