Pure silver nanoparticles(AgNPs) were synthesized using Senecio madagascariensis plant extract and oleic acid as an additional capping agent. The powder X-ray diffraction patterns of the silver nanoparticles were indexed to the face-centred cubic phase of Ag. TEM images of the nanoparticles revealed polydisperse spherical nanoparticles in a 9 to 22 nm range. The GC-MS revealed terpenes as some phytochemicals extracted, which the FTIR bands corroborated. The results confirmed that the increase in oleic acid concentration increased the size of the silver nanoparticles. The nanoparticles' optical band gaps, Eg, were 2.26 – 2.56 eV, which decreased with particle size. The AgNPs exhibited potential antioxidant activity, as demonstrated by the DPPH scavenging assay. The DPPH scavenging activity was highest, with AgNP1 at 80% and an IC50 of 1.668 μg/mL. Fluorescence and ultraviolet (UV) titrations were used to study the interaction of silver nanoparticles (AgNP1) with bovine serum albumin (BSA). The Kapp value of the AgNP1 was calculated to be 3.14 × 104 ± 0.02 Lmol−1, KSV calculated as 7.38 × 104 ± 0.12 M−1. In the study, AgNPs bind to BSA potentially through a static quenching mechanism with one binding site that leads to developing a ground state complex. It is proposed that AgNPs bond to BSA's surface spontaneously based on determining thermodynamic characteristics and binding constants.