IN VITRO ASSESSMENT OF ANTIOXIDANT AND ANTIBACTERIAL ACTIVITY OF GREEN SYNTHESIZED SILVER NANOPARTICLES FROM DIGITARIA RADICOSA LEAVES

Green metallic nanoparticles were creating a new era in the field of green nanotechnology and its applications. Methanolic leaf extract of rare, endemic medicinally important herb, Digitaria radicosa used for the synthesis of silver nanoparticles (SNPs). UV Visible spectrophotometric analysis confirmed the synthesis of green silver nanoparticles indicated by the peak observed at 442nm due to the excitation of surface plasmon resonance in the silver nanoparticles. FT-IR spectroscopic analysis showed the availability of functional groups which may involve in the silver nanoparticles synthesis. X-Ray Diffraction pattern illustrated the characteristic peaks of (111), (122), (231) facets of the centre crystalline and cubic face centred nature of silver nanoparticles. SEM analysis showed that synthesized green silver nanoparticles were of spherical in shape and size of around 90 nm. The free radical scavenging activity of silver nanoparticles were evaluated in vitro by using DPPH scavenging activity, metal chelating activity, reducing power assay and hydrogen peroxide scavenging assays. The antibacterial activity against food borne pathogens such as S. aureus and E .coli were determined by disc diffusion method. The results confirmed that these synthesized green silver nanoparticles identified to have significant in vitro antioxidant potential and good antibacterial activity.Keywords:Green Silver nanoparticles, SNPs, Digitaria radicosa leaf extract, UV Visible spectrophotometry, XRD, FT IR, SEM, in vitro antioxidant assays, antibacterial activity

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Not AvailableTo assess West Nile virus (WNV) infection in wild resident and migratory birds, we tested 3887 samples from 1784 birds belonging to 119 identified species within 30 families collected during 2008-10 from 13 states in India. The serum samples were tested for WNV antibodies initially by a competition ELISA and subsequently by a micro-plaque reduction neutralization test (Micro-PRNT), whereas tracheal and cloacal swabs were subjected to real-time RT-PCR for the detection of the WNV RNA. Twenty six birds (2.46%) out of 1058 tested showed evidence of flavivirus antibodies by ELISA. End point neutralization antibody determinations for WNV and Japanese encephalitis virus (JEV) showed that of the 22 ELISA positive sera, WNV-specific neutralizing antibodies were detected in 17 samples representing nine species of wild birds (residents: Purple swamphen, Little cormorant, Little egret, Black ibis and Spot-billed duck; residents with winter influx: Common coot and Mallard; migratory birds: Ruff and Purple heron), and two samples were positive for both WNV and JEV antibodies. The WNV-specific antibodies were most commonly detected in Mallards and Common coots. WNV genomic RNA was not detected by real-time RT-PCR. The results in this study suggest that wild resident birds are infected occasionally and wild migratory birds rarely with WNV. Additionally, our study provides evidence of WNV infection in eastern and northern India for the first time.Not Availabl