Biogenic synthesis of photosensitive magnesium oxide nanoparticles from oil palm and rubber leaf extracts: antioxidant, antibacterial, and photocatalytic evaluation

Magnesium oxide nanoparticles (MgONPs) were successfully prepared from leaf extracts of Elaeis guineensis (oil palm) and Hevea brasiliensis (rubber). Characterization using Fourier transform infrared spectroscopy, X-ray diffraction, dynamic light scattering, and BET analysis validated the presence of functional groups for stabilization, a face-centered cubic crystal structure, nanoscale dimensions (approximately 100 nm) with mesoporosity and high surface areas of 318.6 m2/g for oil palm and 251 m2/g for rubber. Rubber leaves (RL)-MgONPs had mild aggregation, while oil palm leaves (OPL)-MgONPs were monodispersed and evenly distributed. Antioxidant activity using the DPPH assay showed dose-dependent scavenging capacity with IC50 values of 316 mg/mL for OPL and 495 mg/mL for RL. OPL-MgONPs also displayed enhanced antibacterial properties against Escherichia coli and Staphylococcus aureus. Photocatalytic activity showed high methylene blue degradation (91.63% for OPL) with over 93% mineralization. The reduced size, increased surface area, and mesoporosity of OPL-MgONPs improved their reactive oxygen species activity, indicating their potential as eco-friendly multifunctional nanomaterials.