Green synthesis of silver nanoparticles using aerial parts of Asparagus racemosus Willd: characterization, antioxidant, antidiabetic, cytotoxicity, and antibacterial activities

Abstract

Asparagus racemosus Willd is a well-known medicinal plant due to its various therapeutic aspects. The aerial part of A. racemosus was utilized to formulate cost-effective and environmentally friendly silver nanoparticles through a green approach. The surface plasmon resonance band of A. racemosus-mediated silver nanoparticles (AgNPs-AR) was established at the λ_max of 426 nm in UV-visible analysis, confirming the formation of AgNPs-AR through this green synthesis method. The diameter of spherical-shaped AgNPs-AR was 202 nm. The characterization of AgNPs-AR was done by using Fourier Transform Infrared (FT-IR) spectroscopy, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray (EDX), X-ray Powder Diffraction (XRD), Dynamic Light Scattering (DLS), and Zeta potential analyses. Additionally, the therapeutical potentialities of the AgNPs-AR were established by assessing the antioxidant, antidiabetic, anticancer, and antibacterial properties. The DPPH free radical assay showed potent scavenging ability (IC₅₀: 639 µg/ml). Increasing absorbance with increasing concentration of AgNPs-AR confirmed the reducing power ability of the AgNPs-AR. The α-amylase inhibitory assay demonstrated significant inhibition (IC₅₀: 535 µg/ml), indicating the antidiabetic potential of the AgNPs-AR. They also exhibited notable cytotoxicity (IC₅₀: 57.65 µg/ml) against malignant human kidney cells and excellent antibacterial activity against both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. Thus, the study concluded that the AgNPs-AR demonstrated promising antioxidant, antidiabetic, cytotoxic, and antibacterial activities, which can deliver a new candidate for drug discovery research.