Biogenic synthesis of silver nanoparticles using S1 genotype of Morus alba leaf extract: characterization, antimicrobial and antioxidant potential assessment

Present study deals with synthesis and assessment of antimicrobial and antioxidant activity of silver nanoparticles using aqueous extract of mulberry leaves. The optical study showed the appearance of SPR peak in the range of 423-450 nm affirming nanosilver formation. FTIR analysis indicates the possible involvement of proteins, carbohydrate and secondary metabolites as reducing and capping agents. SEM, TEM and HR-TEM analysis reveals that the synthesized nanoparticles were spherical in shape with particle size ranges between 12 and 39 nm. EDX spectra showed maximum intensity at 3 keV, affirming silver crystal. XRD analysis showed silver nanoparticles were preferentially oriented along (111) revealing crystalline structure. DLS analysis confirms the stability of silver nanoparticles with zeta potential of + 37.4 mV. Silver nanoparticles showed effective antimicrobial activity against both gram positive and gram negative bacteria with highest activity against Salmonella typhimurium with MIC 40 mu g/ml. Further silver nanoparticles also showed dose dependent antioxidant activity against free radicals like DPPH, ABTS(+), superoxide and nitric oxide; besides this nanosilver also performed significant metal chelating activity.