Thermodynamic study on the effects of β-cyclodextrin inclusion with berberine
Thermodynamic study on the effects of β-cyclodextrin inclusion with berberine
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DOI：
10.1016/s1386-1425(01)00536-4
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发表时间：
2002-01-15
影响因子：
4.4
通讯作者：
Zhao, CC
中科院分区：
文献类型：
--
作者：
Yu, JS;Wei, FD;Zhao, CC
研究了小檗碱（Berb）与β-环糊精（β-CD）络合后的荧光增强效应.在20 ℃、pH7.20的水溶液中，α-CD和β-CD与Berb的缔合常数分别为60和137 M ~（-1）.用荧光滴定法研究了温度对β-环糊精与小檗碱形成包合物的影响。由荧光数据计算的焓和熵值为-33.7kJ（.）mol（-1）和74.3J（.）mol（-1.）K（-1）。发现β-CD腔的介电常数约为24，与无水乙醇粗略类比。结果表明，β-环糊精包合反应的主要动力是“高能水”分子从β-环糊精空腔中的挤出和包合物形成时的疏水作用。研究了pH对β-CD与Berb结合的影响.通过吸收光谱和核磁共振谱的测定，进一步研究了β-CD与Berb的包结机理.结果表明，β-CD与Berb形成1：1的包合物. (C)2002 Elsevier Science B. V.保留所有权利。
The fluorescence enhancement of berberine (Berb) as a result of complex with beta -cyclodextrin (beta -CD) is investigated. The association constants of alpha -CD and beta -CD with Berb are 60 and 137 M-1 at 20 degreesC in pH 7.20 aqueous solution. Effects of temperature on the forming inclusion complexes of beta -CD with Berb have been examined through using fluorescence titration. Enthalpy and entropy values calculated from fluorescence data are -33.7 kJ(.)mol(-1) and 74.3 J(.)mol(-1.)K(-1), respectively. It was found that the dielectric constant of beta -CD cavity is about 24 in a rough analogy with absolute alcohol. These results suggest that the extrusion of 'high energy water' molecules from the cavity of beta -CD and hydrophobic interaction upon the inclusion complex formation are the main forces of the inclusion reaction. Effect of pH on the association of beta -CD with Berb was also studied. Mechanism of the inclusion of beta -CD with Berb is further studied by absorption and NMR measurements. Results show that beta -CD forms a 1:1 inclusion complex with Berb. (C) 2002 Elsevier Science B.V. All rights reserved.