Zinc Oxide Nanoparticle Green Synthesis Using Black Cumin Seed Aqueous Extract: Its Characterization and in vitro Anti- Hyperglycaemic Properties

Introduction: α-Amylase and α-glucosidase are carbohydrate metabolizing enzymes that are known to be involved in postprandial hyperglycaemia in diabetic patients. Objective: In a bid to source potent inhibitors of these enzymes, the study synthesized zinc oxide nanoparticles and evaluated the in vitro anti-hyperglycaemic activity. Materials and Methods: The seed aqueous extract of black Cumin (BC) was used as a capping and/or reducing agent to synthesize ZnO NPs from zinc acetate precursor. The BC-ZnONPs were characterized by microscopy (FESEM and HRTEM) and spectroscopy (UV-Vis and EDX) methods. In vitro anti-hyperglycaemic evaluation was based on α-amylase and α-glucosidase inhibition assays. Results: The BC-ZnONPs showed a spherical-to-cubical shape with a 10-50 nm size range. The UV-Vis absorption peaks at 387 and 415 nm suggest the formation of biogenic ZnO NPs. The EDX spectrum revealed 68.92% and 27.49% weight compositions of Zn and O, respectively, to further substantiate ZnO nanoparticle synthesis. The BC-ZnONPs showed notable anti-hyperglycaemic properties with IC₅₀ of 87.72±5.13 and 124.21±15.20 μg/mL against α-amylase and α-glucosidase, respectively. Conclusion: Black Cumin seed extract was a useful biogenic material for synthesizing ZnO NPs. The BCZnONPs showed promising anti-hyperglycaemic properties based on the notable inhibitory activities against α-amylase and α-glucosidase enzymes. Future work may include evaluating the synergistic effects of black Cumin metabolites and ZnONPs, as well as determining the in vivo toxicity profile for safety considerations.