A green route fabrication of copper oxide nanoparticles using Nephelium lappaceum L peel to study antioxidant, antibacterial, antibiofilm, anti-inflammatory, phytochemical, and photocatalytic dye degradation properties

Green synthesis of nanoparticles using plant-derived materials offers an eco-friendly and cost-effective alternative to conventional methods. This study aimed to synthesize copper oxide nanoparticles (CuO NPs) using Nephelium lappaceum L peel extract as a reducing and stabilizing agent, characterize their properties, and evaluate their multifunctional activities. The formation of CuO NPs was confirmed by UV–Vis (262 nm), FTIR (Cu–O stretching at 597.29 cm⁻¹), SEM (spherical morphology), XRD (36.1 nm crystalline size), TEM (irregular shape), and zeta potential (−17.5 mV). The nanoparticles exhibited strong biological activities, including antioxidant scavenging (49 % at 500 µg/mL), anti-inflammatory inhibition (67 % at 500 µg/mL), antibacterial, antibiofilm, and phytochemical activity. A seed germination assay with Eleusine coracana showed enhanced root and shoot growth, confirming low toxicity. Photocatalytic studies revealed 83 % degradation of aniline yellow dye under sunlight. These findings demonstrate that N. lappaceum peel extract is an effective green source for CuO NP synthesis, providing multifunctional materials with promising biomedical and environmental applications.