Antimicrobial and antioxidant activities of Mimusops elengi seed extract mediated isotropic silver nanoparticles

The present study reports the use of Mimusops elengi (M. elengi) fruit extract for the synthesis of silver nanoparticles (Ag NPs). The synthesized Ag NPs was initially noticed through visual color change from yellow to reddish brown and further confirmed by surface plasmonic resonance (SPR) band at 429 nm using UV-Visible spectroscopy. Morphology and size of Ag NPs was determined by Transmission Electron Microscopy (TEM) analysis. X-ray Diffraction (XRD) study revealed crystalline nature of Ag NPs. The prolonged stability of Ag NPs was due to capping of oxidized polyphenols which was established by Fourier Transform Infrared Spectroscopy (FTIR) study. The polyphenols present in M. elengi fruit extract was analyzed by High Pressure Liquid Chromatography (HPLC) and the results revealed the presence of ascorbic acid, gallic acid, pyrogallol and resorcinol. In order to study the role of these polyphenols in reducing Ag+ ions to Ag NPs, analyses of extracts before reduction and after reduction were carried out. In addition, the synthesized Ag NPs were tested for antibacterial and antioxidant activities against Staphylococcus aureus (S. Aureus) and Escherichia coli (E. coli). Ag NPs showed good antimicrobial activity against both gram positive (S. aureus) and gram negative (E. coli) bacteria. It also showed good antioxidant activity as compared to ascorbic acid as standard antioxidant. (C) 2014 Elsevier B.V. All rights reserved.