β-环糊精及其衍生物增加客体分子水溶性的研究进展

β-环糊精及其衍生物对不同结构的客体分子的包合稳定性会因包合介质、包合温度、客体分子大小及氢键的形成等诸多因素的影响而产生较大差异,而环糊精包合物的形成不仅对疏水性客体分子的溶解度、生物利用度、安全性和稳定性有显著影响,还在减小疏水性客体分子刺激性、去除和掩盖其不良气味以及控制其释放速率等方面发挥重要作用。本文对常见β-环糊精衍生物的特点进行了归纳,并重点讨论了黄酮类化合物、多酚类化合物、香豆素类化合物和萜类化合物等客体分子与β-环糊精及其衍生物形成稳定包合物时包合方式的差异以及β-环糊精及其衍生物在增溶方面的应用,为β-环糊精及其衍生物在食品相关领域对不同疏水性功效成分增溶作用的探究提供理论参考。     

超分子结构环糊精及其染整加工中的应用(二)

2包合的机理和方法环糊精(主体)最重要性能之一,是可与客体分子形成包合物.这种超分子结构是由若干个不同物质分子通过非共价键相互形成新的聚集体.环糊精具有广泛的客体,如有机分子、无机离子、络合物,甚至稀有气体.在溶液中形成这类超分子时,主体分子会与溶剂分子竞争客体分子,这就要求主、客体分子之间有选择性地相互作用,如以范德华力、氢键、亲水/疏水性与某些基团结合,或以局部的电荷和空间等共同决定的选择性分子间力,亦称分子识别性能.     

环糊精包合三丁酸甘油酯的分子机制研究

以环糊精(cyclodextrin, CD)为主体,三丁酸甘油酯(tributyrin, TB)为客体,采用共沉淀法制备CD/TB包合物,通过核磁共振、相溶解度、等温滴定微量热及分子模拟对其包合机制进行研究。结果表明,单一环糊精(α-CD、β-CD、γ-CD)均可与三丁酸甘油酯形成包合比为1∶1的包合物,其中β-CD最适于包合三丁酸甘油酯;环糊精包合三丁酸甘油酯是自发进行的微放热过程,焓熵协同驱动促进环糊精包合三丁酸甘油酯,其中熵驱动在包合过程中占主导地位,疏水作用力为主要作用;复配环糊精(α-CD∶β-CD∶γ-CD=2∶7∶1,物质的量之比)包合三丁酸甘油酯过程中的熵变(24.3 cal/mol K)比单一环糊精(β-CD为17.8 cal/mol K)提高了36.52%,同时包合稳定常数提高了79.21%,说明复配环糊精可提供更多与三丁酸甘油酯分子尺寸相匹配的疏水空腔,包合能力更强,从而达到更稳定的包合效果;最终,通过解析单一环糊精包合三丁酸甘油酯的分子对接模型,推测出复配环糊精协同包合三丁酸甘油酯的包合构象。该研究为环糊精包合体系的机制研究提供了参考依据。     

β-环糊精和染料木黄酮包合作用的研究

以β-环糊精与染料木黄酮的摩尔比、包合温度及包合时间为变量设计正交试验优化β-环糊精与染料木黄酮的包合反应工艺参数，利用紫外和红外吸收光谱、热重和导数热重分析、差示扫描量热分析等测试方法对β-环糊精与染料木黄酮的包合物和主、客体分子进行了表征；比较了包合物与游离主、客体的光谱性质的差异，实验结果表明：β-环糊精与染料木黄酮能形成摩尔比为1：1的水溶性好、热稳定性强的包合物，该包合物可广泛应用丁多个领域。     

环糊精模拟酶的研究进展

由于环糊精分子空腔能与客体分子形成包络物，对客体分子具有一定的选择识别能力，使它具有模拟酶的功能。对环糊精单体、修饰环糊精和环糊精聚合物模拟酶的情况进行了综述。     

超分子结构环糊精及其在染整加工中的应用(一)

环糊精是一种环状低聚物,其空腔具有包合某些化学品分子的能力,目前已在医药、日用化工、食品,以及染整工业获得广泛应用.文中介绍了环糊精的由来、性能(安全性)、衍生物、包合机理和方法、应用性能以及形成包合物(超分子结构)的确认.在染整加工中,环糊精的应用可分为一次性和长效性两类.前者通常以生物制剂取代传统的化学助剂用于洗涤和染色.后者则是藉交联或接枝等化学方法将环糊精锚牢在纤维上,当其包合的客体分子释放完后,不仅可再次施加(包合),并可以更换新的客体分子而用于交联和功能整理中.     

环糊精模拟酶的研究进展

由于环糊精分子空腔能与客体分子形成包络物，对客体分子具有一定的选择识别能力，使它具有模拟酶的功能。本文就环糊精单体、修饰环糊精和环糊精聚合物模拟酶的情况进行了综述。     

酸性大红3R与β-环糊精包合体系的光谱研究及应用

采用荧光光谱与紫外-可见光谱研究β-环糊精与工业染料酸性大红3R形成的包合体系.在包合体系最大吸收波长506nm、最佳pH值5.0和最佳包合时间40min条件下,根据Benesi-Hildebrand方程,测定计算出β-环糊精与酸性大红3R的包合比是2:1,包合常数是1.22×106 L2/mol2.考察了不同类型表面活性剂[十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS)、十六烷基三甲基溴化铵(CTAB)及平平加O]对包合体系光谱的影响,阴离子表面活性剂与非离子表面活性剂对包合体系的光谱无影响,而阳离子表面活性剂会改变其光谱特征.同时将SDS、SDBS和平平加O分别应用于酸性大红3R-β-环糊精染色体系中上染柞蚕丝,不匀率均下降.     

槲皮素与环糊精衍生物包合物的理化性质和分子对接研究

槲皮素具有较强的抗氧化活性,对呼吸道炎症和心血管疾病具有一定疗效,在医药行业中受到广泛关注。 但是,槲皮素的水溶性和热稳定性较低,使其在医药行业的应用受到限制。环糊精（cyclodextrins,CDs）是一种 大环分子,能够与客体分子包合形成包合物,从而有效提高客体分子的溶解性、稳定性和生物利用率。本实验制备 槲皮素与β-CD、G-β-CD及G2-β-CD的包合物,利用相溶解度法研究环糊精与槲皮素的包合效果,利用紫外光谱、 傅里叶变换红外光谱、扫描电子显微镜、X射线衍射、热重及差示扫描量热技术表征槲皮素与G-β-CD包合物,借 助分子对接研究槲皮素与G-β-CD包合物的超分子结构。结果显示：槲皮素的溶解度与环糊精的浓度呈线性关系, G-β-CD与槲皮素的包合效果最好,且包合后槲皮素的热稳定性提高。分子对接结果表明槲皮素的C环嵌入G-β-CD 的空腔中形成包合物。     

槲皮素与环糊精衍生物包合物的理化性质和分子对接研究（英文）

槲皮素具有较强的抗氧化活性,对呼吸道炎症和心血管疾病具有一定疗效,在医药行业中受到广泛关注。但是,槲皮素的水溶性和热稳定性较低,使其在医药行业的应用受到限制。环糊精(cyclodextrins,CDs)是一种大环分子,能够与客体分子包合形成包合物,从而有效提高客体分子的溶解性、稳定性和生物利用率。本实验制备槲皮素与β-CD、G-β-CD及G_2-β-CD的包合物,利用相溶解度法研究环糊精与槲皮素的包合效果,利用紫外光谱、傅里叶变换红外光谱、扫描电子显微镜、X射线衍射、热重及差示扫描量热技术表征槲皮素与G-β-CD包合物,借助分子对接研究槲皮素与G-β-CD包合物的超分子结构。结果显示:槲皮素的溶解度与环糊精的浓度呈线性关系,G-β-CD与槲皮素的包合效果最好,且包合后槲皮素的热稳定性提高。分子对接结果表明槲皮素的C环嵌入G-β-CD的空腔中形成包合物。     

Physicochemical characterisation of the supramolecular structure of luteolin/cyclodextrin inclusion complex

The formation of supramolecular inclusion complexes between luteolin and five cyclodextrins namely β-cyclodextrin (β-CD), methyl-β-cyclodextrin (M-β-CD), hydroxyethyl-β-cyclodextrin (HE-β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD) and glucosyl-β-cyclodextrin (G-β-CD) was investigated. Results from phase-solubility studies showed that luteolin formed 1:1 stoichiometric inclusion complexes with these cyclodextrins with the G-β-CD complex displaying the greatest stability constant. The supramolecular structure of the luteolin/G-β-CD complex was investigated by ultraviolet–visible spectroscopy (UV), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). Results showed clearly the formation of a supramolecular complex in which the guest molecule, luteolin, was entrapped inside the cavity of the host, G-β-CD. The close association between luteolin and G-β-CD resulted in changes in some of the characteristic spectral, phase transitional and morphological properties of luteolin. Furthermore, molecular docking study showed that the complex was formed with the B ring of luteolin inserted into the cavity of G-β-CD.     

叶黄素浸膏的环糊精包合作用研究

目的:研究环糊精包合时叶黄素浸膏性能的改进效果.方法:HSCCC及HPLC分析浸膏成分,紫外法测定表观包合常数,研磨法制备包合物,以溶解性及稳定性指标考察包合效果.结果:色谱分析表明,叶黄素浸膏为成分复杂的混合物;叶黄素浸膏与环糊精存在较强的包合作用,且混合环糊精优于单一环糊精;单一环糊精的包合改进效果各异,p一环糊精的增溶效果较差,但稳定性好于羟丙基-β-环糊精;混合环糊精包舍的改进效果明显,尤以β-环糊精/羟丙基-β-环糊精9:1的混合包合性能效果最佳.结论:混合环糊精包合成分复杂的叶黄素浸膏可弥补单一环糊精的不足,包舍物的溶解度和稳定性均能得到明显改善.     

High Relative Humidity In‐Package of Fresh‐Cut Fruits and Vegetables: Advantage or Disadvantage Considering Microbiological Problems and Antimicrobial Delivering Systems?

ABSTRACT:  This hypothesis article states that the high relative humidity (RH) of packaged fresh-cut fruits or vegetables that is associated with spoilage can be used as an advantageous way to deliver antimicrobial compounds using cyclodextrins (CDs) as carriers. CDs can function as antimicrobial delivery systems as they can release antioxidant and antimicrobial compounds (guest molecules) as the humidity levels increase in the headspace. Hydrophobic antimicrobial guests can be complexed with CDs due to the amphiphatic nature of the host. Then, at high RH values, due to the water–CDs interaction, host–guest interactions are weakened; consequently, the antimicrobial molecule is released and should protect the product against the microbial growth. Potential antimicrobial compounds capable of forming complexes with CDs are discussed, as well as possible applications to preserve fresh-cut produce and future research in this area.     

Cyclodextrins and Antioxidants

In recent years, the growth of the functional foods industry has increased research into new compounds with high added value for use in the fortification of traditional products. One of the most promising functional food groups is those enriched in antioxidant compounds of a lipophilic nature. In spite of the numerous advantages reported for such antioxidant molecules, they may also have disadvantages that impede their use in functional foods, although these problems may well avoided by the use of encapsulant agents such as cyclodextrins. This explains the recent increase in the number of research papers dealing with the complexation of different guest molecules possesing important antioxidant properties using natural and modified cyclodextrins. This paper presents a review of the most recent studies on the complexes formed between several important types of antioxidant compounds and cyclodextrins, focusing on the contradictory data reported in the literature concerning to the antioxidant activity of the host/guest molecule complexes, the different complexation constants reported for identical complexes, the bioavailability of the antioxidant compound in the presence of cyclodextrins and recommendation concerning the use of natural or modified cyclodextrins. Moreover, the use of cyclodextrins as antibrowning agents to prevent enzymatic browning in different foods is revised. Finally, we look at studies which suggest that cyclodextrins act as ‘‘secondary antioxidants,” enhancing the ability of traditional antioxidants to prevent enzymatic browning.     

An investigation into the supramolecular structure,solubility, stability and antioxidant activity of rutin/cyclodextrin inclusion complex

The formation of supramolecular inclusion complexes between rutin and four cyclodextrins, namely β-cyclodextrin (β-CD), (2-hydroxypropyl)-α-cyclodextrin (HP-α-CD), (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD) and (2-hydroxypropyl)-γ-cyclodextrin (HP-γ-CD), and the effects of the complexation on the stability and antioxidant activity of rutin were investigated. Results from phase-solubility studies showed that rutin formed 1:1 stoichiometric inclusion complexes with HP-α-CD, β-CD, HP-β-CD and HP-γ-CD; the complexes formed with HP-γ-CD and HP-β-CD had the greatest stability constants, followed by β-CD and HP-α-CD. Thermodynamic studies demonstrate that the inclusion of rutin into HP-β-CD was an exothermic process which occurred spontaneously. Two-dimensional rotating-frame nuclear Overhauser effect spectroscopy (2D ROESY) ¹H NMR analyses show that the A ring of rutin was the part of the molecule that most likely inserted into the cavity of HP-β-CD, thus forming a supramolecular inclusion complex. Formation of such an inclusion complex conferred moderate degrees of protection to rutin from degradation by heat and UV radiation during storage, and significantly enhanced its antioxidant capacity as determined by three different procedures.     

Phase solubility studies and stability of cholesterol/β-cyclodextrin inclusion complexes

BACKGROUND: Cyclodextrins (CDs) are able to enhance the solubility, stability and bioavailability of several bioactive hydrophobic compounds by complex formation. They can also be used for removal of undesired components (such as cholesterol, off‐flavors or bitter components) present in foods. Although many patents account for the use of cyclodextrins for removal of cholesterol from dairy foods, there is no available information on the effect of water on encapsulation efficiency and on the stability of sterols in CDs. The aim of this work was to study the inclusion properties and the factors affecting the encapsulation and stability of cholesterol in β‐cyclodextrin (BCD). The optimum encapsulation conditions (ligand–CD molar ratio, stirring time and temperature), and stability of the complexes as a function of storage time and water content were analyzed. RESULTS: Phase solubility study pointed out the formation of 1:1 stoichiometric complexes between cholesterol and β‐cyclodextrin, which was influenced by temperature variations. The process was shown to be exothermic and energetically favored. The presence of cholesterol greatly modified the BCD water sorption curves, being the amount of adsorbed water smaller in the combined systems. The principal ‘driving force’ for complex formation is the substitution of the high‐enthalpy water molecules by an appropriate hydrophobic ligand. The freeze‐dried complexes probed to be stable at different storage conditions. CONCLUSION: The phase solubility and stability data obtained could be essential for selecting the most suitable conditions when CDs are employed either for removing cholesterol or to incorporate functional ingredients (i.e. sitosterol) in the development of innovative food products. Copyright © 2011 Society of Chemical Industry