The green synthesis of metal nanoparticles is drawing considerable attention for its environmentally safe method where the reducing agent in the synthesis is plant extract for the synthesis of nanoparticles with engineered properties. Here, an effort has been made to conduct a green synthesis and characterization of silver, gold, and copper nanoparticles and assess their catalytic properties. Plant extract-based nanoparticles were synthesized and evaluated by UV-Vis spectroscopy, TEM, XRD, and FTIR, showing distinctive sizes, morphology, and crystal structures. Catalytic activity was assessed using 4-nitrophenol reduction, which showed the silver nanoparticles had maximum catalytic performance, followed by gold and copper nanoparticles. Statistical analysis revealed remarkable differences in the catalytic performances of the nanoparticles. This study points to the promise of green-synthesized nanoparticles for diverse catalytic uses, providing eco-friendly alternatives for industrial processes and environmental remediation.