期刊
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
卷 173, 期 3, 页码 230-237出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.jphotochem.2005.04.002
关键词
cyclodextrins; curcumin; fluorescence enhancement; host-guest inclusion
The effect of alpha-, beta-, and gamma-cyclodextrin (CD) and their hydroxygropylated (HP) derivatives on the solubility and fluorescence of the compound curcumin has been studied. Curcumin, the main constituent of the Indian spice turmeric, is of growing interest due to its wide-ranging pharmaceutical properties. All of these six cyclodextrins significantly increase the aqueous solubility of curcumin, with the greatest solubility observed in HP-gamma-CD. Curcumin forms 2:1 host-guest inclusion complexes with these cyclodextrins, with the strongest complexes formed in the case of HP-beta-CD. These 2:1 complexes are postulated to form when a cyclodextrin host encapsulates each of the two phenyl rings at the ends of the curcumin molecule. The equilibrium constant for encapsulation by the second cyclodextrin host is significantly smaller than that for the first in each case, probably a result of steric bulk of the first cyclodextrin, with deep inclusion of the curcumin molecule, hindering encapsulation by the second cyclodextrin host. In fact, in the case of beta-CD, a 1: 1 host:guest model fit the data just as well, or better than, the 2:1 model. In the case of gamma-CD and HP-gamma-CD, the initial 1:1 complex formed was found to be less fluorescent than the free curcumin; this is postulated to be a result of inclusion of a folded curcumin molecule, which breaks the conjugation along the length of the molecule and hence greatly reduces its fluorescence quantum yield. (c) 2005 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据