Green synthesis of silver nanoparticles from cumaru (Dipteryx odorata) leaf extract

This study evaluated the chemical and antioxidant properties of the ethanolic extract of Dipteryx odorata leaves and its application in silver nanoparticle (AgNP) synthesis. The extract's phytochemical profile revealed phenolic compounds, tannins, flavonoids, and saponins, with notable antioxidant activity, making it suitable for AgNP synthesis. AgNPs were synthesized using an aqueous AgNO3 solution (1 mmol L–1) with varying concentrations of D. odorata extract and energy sources: sunlight (AgNPs-S) and water bath heating (AgNPs-WB). The formation and characteristics of AgNPs were monitored through UV/Vis spectroscopy, Dynamic Light Scattering (DLS), Fourier Transform Infrared (FTIR) spectroscopy, and Transmission Electron Microscopy (TEM). These analyses indicated spherical, monodisperse AgNPs stabilized by phenolic compounds and flavonoids in the extract, with hydrodynamic sizes between 130.3 and 143.5 nm and stability in aqueous media. TEM confirmed the AgNPs’ spherical structure, with diameters ranging from 7 to 12 nm. Antibacterial tests against Escherichia coli and Staphylococcus aureus showed that the AgNPs had effective antibacterial properties, particularly against E. coli, with lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values (MIC = 3.90 and 2.65 µg mL–1 for AgNPs-WB and AgNPs-S, respectively; MBC = 5.27 and 2.65 µg mL–1) compared to AgNO3 controls. These findings suggest that AgNPs synthesized from the ethanolic extract of D. odorata could serve as potent antibacterial agents, especially against multidrug-resistant bacteria. The D. odotata extract demonstrated strong antioxidant activity in DPPH and FRAP assays. The spherical AgNPs measuring 7-12 nm were stable, homogeneous, and exhibited good colloidal stability in aqueous medium. AgNPs from the D. odorata extract showed promising efficacy against E. coli and S. aureus strains.