Comprehensive Evaluation of Peonidin: Antioxidant and Multi-Enzyme Inhibitory Abilities with Molecular Docking...

Anthocyanins are water-soluble plant pigments. They give many plants, fruits, vegetables, and cereal kernels their red, purple, and blue colors. This research aims to reveal the biological properties of peonidin as an anthocyanin. To comprehend the antioxidant capabilities of peonidin, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS^•+), N,N-dimethyl-p-phenylenediamine dihydrochloride radical (DMPD^•+), and 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH^•) scavenging, Fe³⁺-2,4,6-tris(2-pyridyl)-s-triazine (TPTZ), and Cu²⁺ reducing assays were recorded. The IC₅₀ values for peonidin against ABTS^•+, DMPD^•+ and DPPH^• scavenging capabilities were determined to compare with standard antioxidants. ABTS^•+ radical scavenging activity of peonidin had an IC₅₀ value of 15.40 μg/mL, while the IC₅₀ values for BHA, BHT, Trolox, and α-Tocopherol were 12.82, 11.78, 12.67, and 10.83 μg/mL, respectively. DPPH radical scavenging activity of peonidin had an IC₅₀ value of 41.63 μg/mL, while the IC₅₀ values for BHA, BHT, Trolox, and α-Tocopherol were 8.45, 23.10, 6.30, and 18.73 μg/mL, respectively. Enzyme inhibition was studied to investigate the effects of peonidin. The K_i values of peonidin were 114.33, 63.02, 2.99, 9.76, and 15.14 nM toward hCA I, hCA II, AChE, BChE, and α-glycosidase enzymes, respectively. Furthermore, peonidin's interactions with target enzymes BChE, hCA I, hCA II, AChE, and α-glycosidase were investigated by molecular docking. The results suggest that antioxidant-rich peonidin is a plant-based compound with potential use in the treatment of glaucoma, Alzheimer's disease, and diabetes.