Bio-Inspired Synthesis of Gold Nanoparticles Using Leaf Extract of

Background: Bio-based synthesis of metallic nanoparticles has garnered much attention in recent times owing to their non-toxic, environmentally friendly, and cost-effective nature. Methods: In this study, gold nanoparticles (S4-GoNPs) were synthesized by a simple and environmentally friendly technique using an aqueous extract of jamun leaves (JLE) as an effective capping, stabilizer, and reducing agent. JLE was screened for the presence of phytochemicals followed by synthesis, characterization, and evaluation of their antibacterial, antidiabetic, antioxidant, and photocatalytic degradation potentials using standard established procedures. Results: The phytochemical profile of JLE was found to be rich in flavonoids, tannins, terpenoid phenols, anthraquinones, and cardiac glycosides. Its GC-MS analysis revealed the presence of compounds majorly of them as the (1R)-2,6,6-Trimethylbicyclo[3.1.1]hept-2-ene (5.141%), 2(10)-pinene (4.119%), α-cyclopene (5.274%) α,α-muurolene (7.525%), naphthalene, 1,2,3,4,4a,5,6,8a-octahydro-7-methyl-4-methylene-1-(1-methylethyl)-(1.alpha.,4a.beta.,8a.alpha) (8.470%), delta-cadinene (23.246), α-guajene (3.451%), and gamma-muurolene (4.379%). The visual morphology and UV-Vis spectral surface plasmon resonance at 538 nm confirmed the successful synthesis of S4-GoNPs. The average particle size was determined as 120.5 nm with Pdi = 0.152, and -27.6 mV zeta potential. Using the Scherrer equation, the average crystallite size was calculated as 35.69 nm. S4-GoNPs displayed significant antidiabetic properties, with 40.67% of α-amylase and 91.33% of α-glucosidase inhibition activity. It also exhibited promising antioxidant potential in terms of the DPPH (91.56%) ABTS (76.59%) scavenging. It displayed 31.04% tyrosinase inhibition at 0.1 mg/mL. Moreover, it also demonstrated encouraging antibacterial effects with zones of inhibition ranging from 11.02 - 14.12 mm as compared to 10.55-16.24 mm by the reference streptomycin (at 0.01 mg/disc). In addition, S4-GoNPs also showed potential for the photocatalytic degradation of the industrial dye, methylene blue. Conclusion: In conclusion, these results suggest the promising applicability of green-synthesized S4-GoNPs in various sectors, including the biomedical, cosmetic, food, and environmental waste management industries.