Green synthesis, characterization and α glucosidase/α-amylase - inhibitory potential of silver nanoparticles using costus igneus leaf extract

Abstract

The present study reports the green synthesis of silver nanoparticles (AgNPs) using aqueous leaf extract of Costus igneus (insulin plant) and evaluates their antidiabetic potential through α-amylase and α-glucosidase inhibition assays. Phytochemical analysis confirmed the presence of flavonoids, tannins, alkaloids, and proteins that acted as natural reducing and stabilizing agents in nanoparticle formation. Characterization by UV-Vis spectroscopy, FTIR, TEM, XRD, and zeta potential analysis confirmed the formation of stable, spherical, and crystalline AgNPs with strong functional group interactions. CI-AgNPs exhibited superior antioxidant activity in DPPH and FRAP assays compared to crude extracts. Enzyme inhibition studies revealed dose-dependent α-amylase and α-glucosidase inhibition, with CI-AgNPs showing higher efficacy than the plant extract but slightly lower than standard acarbose. In vivo studies using streptozotocin-induced diabetic rats demonstrated significant reduction in blood glucose, improved lipid profile, and protective histopathological changes. These findings highlight CI-AgNPs as promising eco-friendly nanotherapeutics for diabetes management.