Bougainvillea spectabilis as a mediator for the biosynthesis of silver nanoparticles: evaluation of its antimicrobial and cytotoxic effect

The present study describes the biosynthesis, characterization, evaluation of the antimicrobial activity and cytotoxicity of silver nanoparticles (Ag-NPs), synthesized from the aqueous extract of flowers and bracts of the plant Bougainvillea spectabilis . Different extract volumes and concentrations of silver nitrate were evaluated on the morphology, size, and antimicrobial activity of Ag-NPs. The formation of these nanoparticles (NPs) was monitored by ultraviolet -visible spectrophotometry (UV -Vis). Morphology and elemental analysis, were performed by scanning electron microscopy coupled with X-ray energy dispersive spectrophotometry (SEM-EDS), the agglomerates of particles with dimensions ranging from 40 nm to 60 nm were observed. The presence of silver was validated with X-ray diffraction (XRD) analysis. The synthesized Ag-NPs showed antimicrobial activity against some microorganisms isolated from diabetic foot infections, as well as control strains exhibiting greater efficacy against Gram-negative bacteria, than their Gram-positive counterparts. Ag-NPs showed cytotoxic activity in eukaryotic cells depending on their concentration, and in some cases increased cell proliferation at low concentrations. These results invite a more in-depth evaluation of the cytotoxic effect of these nanoparticles synthesized by this methodology for future application in the healthcare field.