Phyto-mediated green synthesis of silver nanoparticles using Acmella oleracea leaf extract: Antioxidant and catalytic activity

Background: Green synthesis has attracted the attention of all researchers due to its nontoxic, energy-saving, cost-effective, and eco-sound features. In the last decades, the usage of medicinal plants or herbs in the form of extract has been pursued to synthesize nanosized materials with added potential benefits that are manifested in various sectors. Aim: In the current study, an easy, economical and environmentally friendly one-pot synthesis technique has been proposed to obtain silver nanoparticles (AgNPs) using Acmella oleracea leaf extract. Materials and Methods: Color transition and ultraviolet-visible spectroscopy were availed to assess the formation of bio-mediated AgNPs while Fourier transform infrared (FTIR) was used to detect the functionalities in the leaf extract and the obtained 4-nitrophenol (NPs). Field emission scanning electron microscope (FESEM) analysis was used to analyze the morphological features of the NPs. The AgNPs were analyzed for the imminent antioxidant impact using 2,2-diphenyl-1-picrylhydrazyl test. In addition, the catalytic potential of AgNPs in reducing NP to 4-aminophenol (AP) was explored. Results: The absorption maximum for AgNPs was obtained at 435 nm and the FTIR analysis confirmed the capping of NPs by secondary metabolites of leaf extract with shift in peaks. FESEM analysis revealed the spherical shape of NPs with size ranging from 45 to 60 nm. AgNPs were found to exhibit significant antioxidant potential with IC₅₀ value as 298.69 μg/mL and efficiently reduced NP to AP. Conclusion: The study signified that A. oleracea extract can be employed for the phyto-mediated synthesis of AgNPs with the latent antioxidant and catalytic applications that could be applied in the bio-medical field and environmental remediation in addition to other potential applications.