BACTERIOSTATIC ACTIVITIES OF ANTIOXIDANT SILVER NANOPARTICLES PREPARED FROM LEAVES OF JUSTICIA ADHATODA AND NYCTANTHES ARBOR-TRISTIS

Silver nanoparticles, prepared from leaf of Justicia adhatoda and Nyctanthes arbor-tristis were tested 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) applied in the present study, nanoparticles showed comparable antioxidant activities with the aqueous leaf extracts. A probable 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 clearly indicated potential use of the nanoparticles against food borne bacteria for application in favor of humans.