Identification and characterization of silver nanoparticles from Erythrina indica and its antioxidant and Uropathogenic antimicrobial properties

Abstract

The plant Erythrina indica comes under Fabaceae family, mainly used for used in traditional medicine as nervine sedative, antiepileptic, antiasthmatic, collyrium in opthalmia, antiseptic. Current study focused synthesize of silver nanoparticles (AgNPs) by E. indica leaf ethanol extract. The green-synthesized AgNPs underwent characterization using multiple analytical techniques, including UV-visible, FTIR, DLS, SEM, TEM, XRD, and EDX, and estimation of their antioxidant activity and antimicrobial activity. Phytochemical analysis identified alkaloids, tannins, saponins, flavonoids, and phenols as secondary metabolites. The Total Phenol Content (TPC) was determined to be 237.35 ± 2.02 mg GAE-1, indicating a substantial presence of phenolic compounds. The presence of AgNPs was verified through UV-Visible analysis at 420 nm, and FT-IR revealed characteristic phenolic functional groups. DLS analysis indicated a narrow size distribution (polydispersity index - PDI: 3.47%), with SEM revealing spherical AgNPs of approximately 20 nm. TEM showed homogeneous, highly polycrystalline AgNPs with lattice spacing at 0.297. XRD analysis demonstrated crystallinity and purity, with distinct reflection peaks corresponding to miller indices of JCPDS card no. 01 087 1473. In vitro, AgNPs exhibited robust antioxidant activity like; DPPH, ABTS, and H₂O₂, surpassing E. indica-assisted synthesis. ABTS assay indicated higher antioxidant activity (81.94 ± 0.05%) for AgNPs at 734 nm, while E. indica extraction showed 39.67 ± 0.07%. At 532 nm, both E. indica extraction (57.71 ± 0.11%) and AgNPs (37.41 ± 0.17%) exhibited H₂O₂ scavenging. Furthermore, AgNPs displayed significant antimicrobial properties, inhibiting Staphylococcus aureus (15.7 ± 0.12 mm) and Candida albicans (10.7 ± 0.17 mm) byfor the concentration of 80 μg/mL. Through the characterizations underscore of the potential of Erythrina indica-synthesized AgNPs, rich in polyphenolic compounds, for pharmacological, medical, biological applications and antipyretic properties.

Keywords: AgNPs-characterization; Antimicrobial activity; Antioxidant; Erithrina indica; Nanoparticle.