Plants provide humans with more than just food and shelter; they are also a major source of medications. The purpose of this research was to investigate the antioxidant and hypoglycemic potential of green synthesized CeONPs using Mentha royleana leaves extract. The morphological and physicochemical features of CeONPs were evaluated by UV-Visible spectrophotometry, Scanning Electron Microscopy, Energy Dispersive X-rays and Fourier-transform infrared spectrometry, Dynamic light scattering, Atomic Force Microscopy, Zeta Potential. The average size range of synthesized CeONPs diameter between 46 and 56 nm, crystalline in shape, with Polydispersity index value of 0.2 and subatomic particles mean diameter was 4.5-9.1 nm. The antioxidant capability of CeONPs was assessed using DPPH, ABTS+, hydrogen peroxide, hydroxyl radical scavenging, and reducing power tests. The hypoglycemic potential of CeONPs was investigated using alpha-amylase, alpha-glucosidase, glucose absorption by yeast cells, and antisucrase. The effective concentrations were 500 and 1000 µg/ml found good in suppressing radical species. To explore the hypoglycemic potential of CeONPs, alpha-amylase, alpha-glucosidase, glucose absorption by yeast cell, and antisucrase assays were performed. Glucose absorb by yeast cells assay was tested for three distinct glucose concentrations: 5 mmol/L, 10 mmol/L, and 25 mmol/L. Green synthesize CeONPs showed a dose-dependent response, higher concentrations of CeONPs imposed a stronger inhibitory impact on the catalytic site of enzymes. This study suggest that CeONPs could possibly binds to the charge carrying species and act as competitive inhibitor which slow down the enzyme substrate reaction and prevents enzymatic degradation. The study's findings were outstanding, which bodes well for future medicinal applications of CeONPs.