Antioxidant and Enzyme Inhibitory Potential of Mespilus germanica L. Leaves: A Phytochemical and Molecular Docking Study

Abstract

Mespilus germanica L. (medlar) leaves, though used in traditional medicine, have been poorly studied scientifically. This study presents the first comprehensive evaluation of their phytochemical content, antioxidant activity, and enzyme inhibition potential. The extract exhibited high levels of phenolics (240.556 mg GAE/g) and flavonoids (77.204 mg QE/g). UPLC-MS/MS analysis revealed chlorogenic acid (65356.29 ng/mL) as the major compound, followed by epicatechin and ellagic acid. Antioxidant assays demonstrated strong activity across several methods, particularly in the CUPRAC test, where it outperformed standard antioxidants. In radical scavenging assays, the extract showed notable activity with IC50 values of 9.002 mu g/mL (DPPH) and 4.748 mu g/mL (ABTS). Enzyme inhibition studies indicated potent activity against carbonic anhydrase isoenzymes (CA I: IC50 = 0.0285 mu g/mL; CA II: IC50 = 0.0261 mu g/mL), significant inhibition of acetylcholinesterase (IC50 = 0.0018 mu g/mL), and superior alpha-glucosidase inhibition compared to acarbose (IC50 = 0.0057 mu g/mL vs. 0.0147 mu g/mL). Molecular docking confirmed strong interactions of chlorogenic acid with these enzymes, supporting the in vitro results. Overall, medlar leaves demonstrate promising therapeutic potential for diseases like diabetes, Alzheimer's, and glaucoma. This study establishes medlar leaves as a promising source for natural drug discovery and fills a significant gap in the scientific literature.