The methods of ultraviolet and infrared spectroscopy and quantum chemical modeling have been used to evaluate the parameters of the formation of a supramolecular inclusion complex between the flavonoid quercetin and the hydroxypropyl-β-cyclodextrin molecular container. The solubility of quercetin in water has been shown to increase by a factor of more than 50 when included in a supramolecular complex with 16 mM hydroxypropyl-β-cyclodextrin. It has been demonstrated that bioavailability of quercetin is improved after encapsulation with hydroxypropyl-β-cyclodextrin. The association constant for the inclusion complex of quercetin and hydroxypropyl-β-cyclodextrin (1 : 1) has been evaluated by the Higuchi-Connors method to be 3275 ± 448 М–1. The formation of the inclusion complex results in considerable changes in the vibrational spectra of components compared to the spectrum of the physical mixture of quercetin and hydroxypropyl-β-cyclodextrin. This difference can be explained by structural changes of the components due to hydrogen bond formation. The molecular modeling of the inclusion complex has shown that the geometry and properties of the components change after encapsulation of quercetin molecule (“guest”) inside the cavity of β-cyclodextrins (“host”). The torsion angles between the rings of the planar quercetin molecule in the complexes with β-cyclodextrin and hydroxypropyl-β-cyclodextrin have been evaluated to be 149.5° and 138.7°, respectively.

中文翻译：

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槲皮素与 β-环糊精的包合物：紫外和红外光谱和量子化学建模

紫外和红外光谱和量子化学建模方法已被用于评估黄酮类槲皮素和羟丙基-β-环糊精分子容器之间形成超分子包合物的参数。当包含在具有 16 mM 羟丙基-β-环糊精的超分子复合物中时，槲皮素在水中的溶解度已显示增加 50 倍以上。已经证明槲皮素的生物利用度在用羟丙基-β-环糊精封装后得到改善。槲皮素和羟丙基-β-环糊精 (1:1) 包合物的缔合常数已通过 Higuchi-Connors 方法评估为 3275 ± 448 М–1。与槲皮素和羟丙基-β-环糊精的物理混合物的光谱相比，包合物的形成导致组分的振动光谱发生相当大的变化。这种差异可以通过氢键形成导致的组分结构变化来解释。包合物的分子模型表明，将槲皮素分子（“客体”）包裹在 β-环糊精（“主体”）的空腔内后，组分的几何形状和性质发生了变化。β-环糊精和羟丙基-β-环糊精的复合物中平面槲皮素分子环之间的扭转角分别为149.5°和138.7°。这种差异可以通过氢键形成导致的组分结构变化来解释。包合物的分子模型表明，将槲皮素分子（“客体”）包裹在 β-环糊精（“主体”）的空腔内后，组分的几何形状和性质发生了变化。β-环糊精和羟丙基-β-环糊精的复合物中平面槲皮素分子环之间的扭转角分别为149.5°和138.7°。这种差异可以通过氢键形成导致的组分结构变化来解释。包合物的分子模型表明，将槲皮素分子（“客体”）包裹在 β-环糊精（“主体”）的空腔内后，组分的几何形状和性质发生了变化。β-环糊精和羟丙基-β-环糊精的复合物中平面槲皮素分子环之间的扭转角分别为149.5°和138.7°。