Green Synthesis of Silver Nanoparticles Using Aqueous Extract of Selaginella moellendorffii, a Himalayan Pteridophyte and its Catalytic activities.

Abstract

Nanotechnology is presently a developing field that provides various novel ways to form the nanoparticles also by exploring the biological sources. Different fractional extracts were extracted from the plant leaves. The present study focuses on different fractions, aqueous, methanolic, pet-ether and chloroform extract preparation. The aqueous extract is used for the AgNPs biosynthesis using the plant aqueous extract as reducing, capping and as a stabilizing agent. Ag+ ions, when exposed to Selaginella moellendorffii plant leaf extract, were reduced and resulted in a colour change, indicating the formation of AgNPs. The AgNPs synthesis was confirmed by UV-Vis Spectrophotometer, FTIR, DLS and Zeta Potential. The absorption peak was observed at 420 nm. From the DLS study, we came to know that the hydrodynamic size of the synthesized AgNPs is 91 nm in counts and the stability of the nanoparticles in the solution, whereas the FTIR analysis shows that the functional groups like N-H, O-H, C-H, C-N, and C-X are present in the aqueous plant extract which undergoes shift in the peak position after the formation of AgNPs. Finally, the Qualitative analysis was done to confirm the presence of various phytochemicals and it was analyzed that the chemical compounds like saponins, tannins, phenolic compounds, alkaloids, steroids and glycosides are present in the plant extract. Various catalytic activities were observed for Selaginella moellendorffii as it showed 90.3% degradation of pesticide, 73.7% degradation of p-nitrophenol, 97.2% degradation of Rhodamine B dye and 94.1% degradation of Methylene Blue dye which was seen with the PAgNPs at different time intervals. The antibacterial activity of PAgNPs and aqueous extract was seen with MIC method against gram-negative bacteria. Thus the IC50 for PAgNPs and plant extract is 3.3 and 5.1 μg/ ml respectively.