Departamento de Bioquímica y Biología Molecular A, Facultad de Biología. Regional Campus of International Excellence "Campus Mare Nostrum", Universidad de Murcia, E, 30100, Murcia, Spain.
Departamento de Bioquímica y Biología Molecular A, Facultad de Biología. Regional Campus of International Excellence "Campus Mare Nostrum", Universidad de Murcia, E, 30100, Murcia, Spain.
Talanta. 2022 Jun 1;243:123336. doi: 10.1016/j.talanta.2022.123336. Epub 2022 Feb 26.
The ability of cyclodextrins to enhance the water solubility of lipophilic compounds is used to modify the water-based Oxygen Radical Absorbance Capacity (ORAC) method to measure antioxidant activity in vitro. However, the use of these solubility enhancers may alter fluorescent readings, which has led to contradictory results being described in the literature. The low specificity of these oligosaccharides and their controlled release effect can result in cyclodextrins forming inclusion complexes with other reagents in the assay, changing the kinetics. In this study, the cause of cyclodextrins' interference in the ORAC method is evaluated through a physicochemical and computational approach. Cyclodextrins showed a clear increase in the fluorescent signal both in the presence and absence of the antioxidant oxyresveratrol, the precise effect being dependent on the type and concentration of cyclodextrin. Although the glucidic nature of cyclodextrins could play a minimal role in this effect, it seems that the main cause was the encapsulation of other substrates in the reaction, fluorescein and AAPH.
环糊精能够提高疏水性化合物的水溶性，因此被用于改良基于水相的氧自由基吸收能力（ORAC）法，以测量体外抗氧化活性。然而，这些增溶剂的使用可能会改变荧光读数，这导致文献中出现了相互矛盾的结果。这些低聚糖的非特异性及其控制释放作用可能导致环糊精与测定中的其他试剂形成包合物，从而改变动力学。在这项研究中，通过物理化学和计算方法评估了环糊精在 ORAC 方法中的干扰原因。环糊精在存在和不存在抗氧化剂氧白藜芦醇的情况下均显示出明显的荧光信号增加，确切的影响取决于环糊精的类型和浓度。尽管环糊精的糖性质可能在这种影响中起很小的作用，但似乎主要原因是其他底物（荧光素和 AAPH）在反应中的包封。
