Biosynthesis of Silver Nanoparticles Using Capsicum chinense Extract: From Synthesis Approach to Antibacterial Efficacy

Abstract The twelve principles of green chemistry represents an actual concern in most nanotechnology developments, highlighting the less use of hazardous chemicals in synthesis. Therefore, this study investigates the green synthesis of silver nanoparticles (AgNPs) using ethanolic extracts of Capsicum chinense (Murupi pepper) and evaluates their antibacterial potential. Extracts from fresh and dried fruits, prepared with varying ethanol concentrations (46%, 70%, and 92.8%), were chemically characterized for phenolics, flavonoids, and antioxidant activity. LC-MS analysis identified capsaicin, dihydrocapsaicin, and various flavonoids and polyphenolic compounds, which act as crucial reducing and stabilizing agents during AgNPs formation. Stable, predominantly spherical nanoparticles with an average core size of 37 ± 17 nm, were produced using silver nitrate precursor at 3 mM of concentration from the 92% ethanolic extract and 300 𝜇L of volume, particularly from dried fruit extracts, showing zeta potentials close to − 30 mV and hydrodynamic diameters generally above 100 nm. The antibacterial activity against E. coli, was verified with the lowest MIC for AgNPs suspension at 92% and 3 mM of precursor in 0.50 mg/mL, whereas the best ethanolic extracts (70% and 92.8%) showed an MIC of 12.50 mg/mL, the antimicrobial activity is predominantly associated with the presence of the nanoparticles rather than the extract components or the solvent alone. These results highlight Capsicum chinense as a promising bioresource for the sustainable synthesis of nanomaterials and the development of environmentally friendly antimicrobial agents.