NMR spectra and structures of oridonin derivatives complexes with β‐cyclodextrin |
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Authors: | Wei Liu Bing Zhao Yin‐Chao Li Hong‐Min Liu |
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Institution: | New Drug Research and Development Center, School of Pharmaceutical Science, Zhengzhou University, Zhengzhou 450001, P. R. China |
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Abstract: | Complexations between three oridonin derivatives and β‐cyclodextrin (βCD) were studied by nuclear magnetic resonance (NMR) method. Job's plots for complexes were depicted by 1H NMR spectra chemical shifts, which proved the 1:1 stoichiometry inclusion complex formation between each derivative and βCD. Two‐dimensional rotating frame overhauser effect spectroscopy (2D ROESY) support the above conclusion and also proved that ring A of each oridonin derivative deeply enters into hydrophobic cavity from the wider rim and the other parts are outside the cavity. Apparent formation constants (Ka) of complexes between three oridonin derivatives and two CDs are calculated according to Scott's equation. Copyright © 2011 John Wiley & Sons, Ltd. |
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Keywords: | NMR 1H ROESY oridonin derivative β ‐cyclodextrin host‐guest complex 3D geometry |
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