Biochemical Analysis and Characterization of Silver Nanoparticles Synthesized by the Endophytic Fungus Plectosphaerella oligotrophica S8A26 Associated with Anaphalis contorta

Abstract

Endophytic fungi associated with medicinal plants produce compounds that have vast biological activities. Anaphalis contorta is a highly therapeutic plant that has been used in traditional medicine by various communities. In the present study, the endophytic fungus Plectosphaerella oligotrophica S8A26 was isolated from the stem part of A. contorta and assessed for its plant growth promotion abilities, and showed positive results for phosphate solubilization and ammonia production. The secondary metabolites were analyzed for the presence of seven biochemicals, which indicate the presence of flavonoids, phenols, saponins, and steroids. The total flavonoid content and total phenolic content were recorded to be 25.67 µg of QE/mg of EE and 5.06 µg of GAE/mg of EE, respectively. The isolate was allowed to synthesize silver nanoparticles and characterized using X-ray diffraction, Energy Dispersive X-ray, Particle size distribution, and Zeta potential. XRD analysis has shown the AgNPs are crystalline with an average size of 24.81 nm. EDX study reveals silver as the main component with 48.63%. Particle size distribution indicates that the majority of the particles occur in the size range of 65–70 nm. Zeta potential value of −31.8 mV shows that the AgNPs are stable. Studies like the biological activities of the endophyte as well as AgNPs, secondary metabolite profiling, and the isolation of bioactive compounds would constitute important future research.