In vitro Enzyme Inhibition and Radical Scavenging Activity, and in silico Studies of Mespilus germanica L. (Rosaceae) Fruit Beverage (Fruit juice) and Molasses

Natural products are a significant source of antioxidant and enzyme-inhibitory agents relevant to neurodegenerative diseases. Mespilus germanica L. (medlar) fruits are traditionally consumed. However, enzyme inhibition and antioxidant activities have not been investigated in relation to the molasses and juice of medlar fruits to date. This study aimed to evaluate the antioxidant capacity and acetylcholinesterase (AChE) inhibitory activity of traditionally prepared M. germanica fruit juice and molasses, and to characterize potential bioactive phytochemicals through in silico molecular docking, molecular dynamics (MD) simulation, and ADMET profiling. Antioxidant activities were measured by ABTS and DPPH assays, and AChE inhibition was assessed using a modified Ellman method. Undiluted fruit juice demonstrated the highest radical scavenging activity against ABTS (98.49%) and DPPH (76.36%), as well as the strongest AChE inhibition (75.51% at 325 µL/mL) compared to molasses and 10-fold diluted fruit juice. Molecular docking and MD simulation results indicated strong interactions of α-tocopherol (−9.4 kcal/mol-1; ΔG-bind ≈ −53.07 kcal/mol-1), chlorogenic acid (−8.7 kcal/mol-1; ΔG-bind ≈ −36.92 kcal/mol-1), and neochlorogenic acid (−8.5 kcal/mol-1; ΔG-bind ≈ −31.25 kcal/mol-1) with AChE. Research findings indicate that M. germanica fruit juice prepared traditionally contains active compounds demonstrating significant antioxidant activities and AChE-inhibitory effects. The promising potential of α-tocopherol and chlorogenic acid derivatives stands out among other compounds for the treatment of neurodegenerative diseases.