The reduced level of dopamine at midbrain (substantia nigra) leads to Parkinson disease by the influence of monoamine oxidation process of monoamine oxidase B (MAO-B) enzyme. This disease mostly affects the aged people. Reports outline that the naringenin molecule acts as an inhibitor of MAO-B enzyme and it potentially prevents the development of PD. To elucidate the binding mechanism of naringenin with MAO-B, we performed the molecular docking, QM/MM and molecular dynamics (MD) simulations. The molecular docking results confirm that the naringenin strongly binds with the substrate binding site of MAO-B enzyme (-12.0 kcal/mol). The low values of RMSD, RMSF and Rg indicate that the naringenin – MAO-B complex is stable over the entire period of MD simulation. Naringenin forms strong interaction with the orient keeper residue Tyr326 and other binding site residues Leu171, Glu206 and these interactions were maintained throughout the MD simulation. It is also important to block the function of MAO-B enzyme. The QM/MM study coupled with the charge density analysis reveals the charge density distribution and the strength of intermolecular interactions of naringenin-MAO-B complex. The above results suggest that this molecule is a potential inhibitor of MAO-B enzyme.

中脑（黑质）多巴胺水平降低，受单胺氧化酶 B (MAO-B) 酶的单胺氧化过程的影响，导致帕金森病。这种疾病主要影响老年人。报告概述了柚皮素分子作为 MAO-B 酶的抑制剂，有可能预防帕金森病的发展。为了阐明柚皮素与 MAO-B 的结合机制，我们进行了分子对接、QM/MM 和分子动力学 (MD) 模拟。分子对接结果证实柚皮素与MAO-B酶的底物结合位点(-12.0 kcal/mol)强烈结合。RMSD、RMSF 和 Rg 的低值表明柚皮素 - MAO-B 复合物在整个 MD 模拟期间保持稳定。柚皮素与东方守护者残基 Tyr326 和其他结合位点残基 Leu171、Glu206 形成强烈的相互作用，并且这些相互作用在整个 MD 模拟中得以维持。阻断 MAO-B 酶的功能也很重要。QM/MM 研究与电荷密度分析相结合，揭示了柚皮素-MAO-B 复合物的电荷密度分布和分子间相互作用的强度。上述结果表明该分子是MAO-B酶的潜在抑制剂。