Synergistic Phytochemical and Nanotechnological Exploration of <i>Melia azedarach</i> With Silver Nitrate: Elucidating Multifaceted Antimicrobial, Antioxidant, Antidiabetic, and Insecticidal Potentials

Plants are a rich source of bioactive compounds with significant pharmaceutical and health applications. This study explores the phytochemical, therapeutic, and phytotoxic properties of Melia azedarach by analyzing extracts from its bark, flowers, leaves, and fruits using six solvents: ethanol, methanol, acetone, hexane, chloroform, and distilled water. Twenty-one phytochemical tests were conducted, revealing significantly positive results for various tests. However, the ethanolic and methanolic flower extracts yielded no significant results in other tests. The highest total phenolic content was found in the chloroform extract of the leaves (96 ± 0.01 mg/100 g), and the highest antioxidant activity was observed in the ethanolic and hexane leaf extracts, with a 98% DPPH scavenging rate. Antibacterial testing showed significant efficacy against Serratia marcescens, Bacillus subtilis, Kluyvera spp., and Pseudomonas spp., with p values < 0.0001. The fruit chloroform extract demonstrated the highest alpha-amylase inhibition (93 ± 0.05), while the ethanolic leaf extract had the greatest tumor inhibition (85.6 ± 0.5). Insecticidal assays revealed that the acetone bark extract had the highest control values (56% and 57%). Due to their higher reducing potential, the leaves were used to biosynthesize silver nanoparticles (AgNPs), characterized by UV-Vis spectroscopy, EDX, and SEM, revealing an average particle size of 20-30 nm and spherical morphology. The AgNPs exhibited excellent antibacterial, antioxidant, antidiabetic, and insecticidal activities. These findings highlight the potential of M. azedarach and its AgNPs for developing novel therapeutic agents.