University of Maribor, Faculty of Chemistry and Chemical Technology, Smetanova ulica 17, SI-2000 Maribor, Slovenia.
University of Maribor, Faculty of Chemistry and Chemical Technology, Smetanova ulica 17, SI-2000 Maribor, Slovenia; University of Primorska, Faculty of Mathematics, Natural Sciences and Information Technologies, Glagoljaška ulica 8, SI-6000 Koper, Slovenia; Institute of Environmental Protection and Sensors, Beloruska ulica 7, SI-2000 Maribor, Slovenia.
Food Chem. 2025 Jan 15;463(Pt 3):141377. doi: 10.1016/j.foodchem.2024.141377. Epub 2024 Sep 19.
This study explores the antioxidative activities of xanthohumol (XN) and isoxanthohumol (IXN), prenylated flavonoids from Humulus lupulus (family Cannabaceae), utilizing the oxygen radical absorption capacity (ORAC) and ferric reducing antioxidant power (FRAP) assays along with computational Density Functional Theory methods. Experimentally, XN demonstrated significantly higher antioxidative capacities than IXN. Moreover, we determined IXN pKa values using the UV/Vis spectrophotometric method for the first time, facilitating its accurate computational modeling under physiological conditions. Through a thermodynamic approach, XN was found to efficiently scavenge HOO• and CHO• radicals via Hydrogen Atom Transfer (HAT) and Radical Adduct Formation (RAF) mechanisms, while CHOO• scavenging was feasible only through the HAT pathway. IXN exhibited its best antioxidative activity against CHO• via both HAT and RAF mechanisms and could also scavenge HOO• through RAF. Both Single Electron Transfer (SET) and Sequential Proton Loss-Electron Transfer (SPLET) mechanisms were thermodynamically unfavorable for all radicals and both compounds.
本研究利用氧自由基吸收能力（ORAC）和铁还原抗氧化能力（FRAP）测定法以及计算密度泛函理论方法，探索了来自大麻科葎草属（Humulus lupulus）的类黄酮化合物黄腐酚（XN）和异黄腐酚（IXN）的抗氧化活性。实验表明，XN 的抗氧化能力明显高于 IXN。此外，我们首次使用紫外/可见分光光度法测定了 IXN 的 pKa 值，从而能够在生理条件下对其进行准确的计算建模。通过热力学方法，发现 XN 通过氢原子转移（HAT）和自由基加合物形成（RAF）机制有效地清除 HOO•和 CHO•自由基，而 CHOO•的清除仅通过 HAT 途径可行。IXN 通过 HAT 和 RAF 机制对 CHO•表现出最佳的抗氧化活性，并且还可以通过 RAF 清除 HOO•。对于所有自由基和两种化合物，单电子转移（SET）和顺序质子损失-电子转移（SPLET）机制在热力学上都是不利的。
