Plant Mediated Synthesis of Silver Nanoparticle From Helianthus annus L. Seeds and Evaluation of their Antioxidant Potential and Effect of Phytochemicals on Capsicum frutescens L.

Abstract

Nanotechnology is a scientific field that provides endless prospects for growth in industries, including agriculture, pharmaceuticals, the industrial sector, the environment, and stress tolerance. AgNPs were green-synthesized from Helianthus annuus L. seeds. UV, SEM, and EDX analyses were used to characterize the samples. The nanoparticles were validated using UV-Vis absorption spectroscopy at wavelengths ranging from 300 to 800 nm. SEM observations reveal that the silver nanoparticles exhibit a homogeneous distribution and spherical shape. EDX analysis revealed exposure, and the structure confirmed the presence of pure silver in the synthesized silver nanoparticles. To validate the crystalline nature of the AgNPs, the dried powdered sample was subjected to the emission peaks of 20.0 kV = 34.39, which corresponded to the silver crystal planes. Green-synthesized AgNPs were evaluated for their in vitro antioxidant and biostimulant effects on Capsicum frutescens L. The highest percentages of inhibition were observed in DPPH* (41.79%), ABTS+ (78.65%), H₂O₂ (48.87%), hydroxyl radical scavenging (25.98%), and total antioxidant activity (1.458±0.010 mg/g). The effects of AgNPs at different concentrations (0, 1, 2, 3, 4, and 5 mg/mL) on seed germination, growth, and phytochemicals in Capsicum frutescens L. were studied. Lower concentrations of AgNPs (1 mg/mL and 2 mg/mL) had a greater effect on Capsicum frutescens L. growth and increased biochemical and Phytochemical content.