Green Synthesis and Quality-by-Design Optimization of Dacryodes edulis-Derived Silver Nanoparticles with Broad-Spectrum Antiviral and Antimicrobial Activity

The rising incidence of viral infections demands the creation of innovative, biocompatible antiviral drugs with broad-spectrum effectiveness. This study combines the green synthesis, optimization, and characterization of silver nanoparticles (AgNPs) utilizing Dacryodes edulis (D. edulis) extract, assessing their antiviral, and antimicrobial characteristics. AgNPs were synthesized through the bio-reduction of silver nitrate with D. edulis water extract as a reducing, capping and stabilizing agent. The synthesis was refined through a Design of Experiments methodology. The characterization techniques, UV-Vis, Fourier-transform infrared, transmission electron microscopy, and dynamic light scattering, validated the successful synthesis of AgNPs with an average size of 101.56 ± 28.22 nm (TEM) and 156 ± 0.81 nm (DLS), a polydispersity index of 0.34, and a zeta potential of −22 mV. High-resolution liquid chromatography–tandem mass spectrometry analysis identified some bioactive compounds which enhance the antimicrobial and antiviral properties of the samples. Enzyme kinetics experiments revealed substantial inhibitory efficacy against the SARS-CoV-2 papain-like protease (PL-pro), with AgNPs exhibiting a lower IC₅₀ (0.271 ± 0.051 mg/mL) than the D. edulis extract (0.337 ± 0.043 mg/mL). The AgNPs exhibited MIC of 0.063 mg/mL for E. coli, 0.125 mg/mL for S. aureus and 0.08 mg/mL for S. pyrogens. The corresponding MBC values were 0.125 mg/mL, 0.25 mg/mL and 0.31 mg/mL, respectively. The fungal strains C. glabrata and C. albicans displayed MIC of 0.63 mg/mL and 0.31 mg/mL, respectively, and MBC values of 0.63 mg/mL and 0.31 mg/mL, respectively. This study underscores the potential of D. edulis-derived AgNPs as a cost-efficient, environmentally sustainable, and highly bioactive antibacterial and antiviral nanomaterial, facilitating the advancement of nanotechnology-based therapies for viral infections.