Brassica juncea, a plant known for its anticancer and antioxidant characteristics, is rich in glucosinolates, flavonoids, carotenoids, and phenolic acids. AEBJ exhibited a high concentration of total flavonoids, measuring 201.09 ± 0.232 mg/g in terms of quercetin equivalents. However, it had a relatively lower total phenolic content, measuring 49.43 ± 1.114 mg/g in terms of tannic acid equivalents. The structural characterisation of silver nanoparticles was performed using UV-Visible spectroscopy, followed by the study of these nanoparticles utilising surface plasmon resonance (SPR) measurements. The interaction between silver ions and extracts of Brassica juncea was seen, and the presence of AgNPs was verified through the detection of a visible peak at 425 nm. The Silver Nanoparticle (BJ 1) effectively suppressed the generation of DPPH radicals within the concentration range of 10-100 µg/ml. The linear regression coefficients for this inhibition were calculated to be 0.9869 and 0.9488, respectively. The IC50 values for Silver Nanoparticle (BJ 1) and BHT were 45.413 and 50.173, respectively. Silver Nanoparticle (BJ 1) exhibited a decrease in the conversion of ferricyanide to ferrocyanide as the concentration increased from 50-250 µg/ml. This was accompanied by an increase in the absorption of green light at a wavelength of 700 nm. The investigation into the antibacterial activity of silver nanoparticles (BJ 1) and Brassica juncea extracts against Escherichia coli has demonstrated substantial potential as antimicrobial agents. The findings indicate that both drugs demonstrate inhibitory effects on the growth of E. coli, with the concentration levels playing a substantial influence. This implies a mutually beneficial interaction between the two drugs, which could potentially amplify their efficacy in fighting bacterial infections. Greater doses of Brassica juncea extract exhibited bigger areas of inhibition, so validating its bioactive activities against pathogenic microorganisms. Furthermore, the Silver nanoparticle (BJ 1) had a potent antibacterial impact as a result of their capability to disturb bacterial cell membranes and impede metabolic activities. The combination of these two medicines has the potential to enhance therapy efficacy in clinical settings. Subsequent investigations should delve into the mechanisms underlying their antibacterial properties and evaluate their safety profiles for future medicinal uses.