Enhanced antidiabetic and antioxidant properties of gold nanoparticles green synthesized using blossom extract of Azadirachta indica: In vitro studies

Abstract

This study describes the in situ biosynthesis of gold nanoparticles (AuNPs) using neem blossom (Azadirachta indica) extract with enhanced in vitro anti-diabetic and antioxidant properties. The formation of AuNPs was confirmed by the characteristic optical response through the surface plasmon resonance (SPR) band observed around 530 nm. The effect of phytochemical in the formation of AuNPs was investigated using Fourier-transform infrared spectroscopy (FTIR). The effect of reaction parameters such as temperature, pH and precursor concentration on the size and surface morphology of AuNPs was optimized using the SPR band. The metallic form of phytosynthesised AuNPs was confirmed by X-ray photoelectron spectra (XPS) results with a distinctive binding energy difference of 4f shells ΔE = 3.8 eV. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) studies confirmed the crystalline nature of the particles formed. The antioxidant property of AuNPs demonstrated the influence of phytochemical surfactants coated on the surface of AuNPs and the results revealed the higher antioxidant (90 %) efficiency compared to standard ascorbic acid. phytosynthesised AuNPs demonstrated 79 % enzyme inhibition efficiency in α-amylase assays. The antimicrobial evaluation results revealed the exceptional microbicidal efficacy of AuNPs against both gram-positive and gram-negative bacteria. Phytochemically activated AuNPs showed improved antioxidant, antimicrobial and antidiabetic properties and it could be a promising candidate for biological applications in medicine.