WITHDRAWN: Characterization, antioxidant and antimicrobial activity of silver nanoparticles synthesized using marine endophytic fungus- Cladosporium cladosporioides

Abstract

Abstract Myconanotechnology (synthesis of nanoparticles using fungi) is one of the upcoming fields of research and generating new avenues and applications in medicine. Of late, marine floras such as marine endophytic fungi are exploited by the scientific community for various studies as they contain myriad of bioactive molecules. In the present study, we have studied the biogenic synthesis of silver nanoparticles using Cladosporium cladosporioides and its antioxidant as well as antimicrobial activity. C.cladosporioides was isolated from brown algae, Sargassum wightii . The identity of the fungus was established by comparing its 18 s rDNA sequence (GenBank accession no- KT384175). Silver nanoparticles (AgNPs) were characterized by UV-Visible spectrophotometer (UV-VIS), Field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). AgNPs were tested for free radical scavenging activity by DPPH method and antimicrobial activity by well in agar method. The particle sizes of AgNps were within 100 nm. The reduction of silver metal was confirmed by the UV–Vis spectrum of the solution and showed surface plasmon resonance. AgNPs showed significant antioxidant potential and the activity was comparable to the standard ascorbic acid. AgNPs also showed significant antimicrobial activity. An attempt was made to understand the mechanism of myco synthesis of AgNPs. The results showed the involvement of NADPH-dependant reductase in the formation AgNPs. To our best of knowledge, this is the first report on the synthesis of silver nanoparticles using endophytic fungus isolated from S. wightii . Further, in vivo studies at the molecular level will help in the development of novel broad- spectrum antimicrobial agent.