Structure and intramolecular flexibility of beta-cyclodextrin complex with (-)-epigallocatechin gallate in aqueous solvent.
The probable structure of the inclusion complex of beta-cyclodextrin (beta-CD) and (-)-epigallocatechin gallate (EGCg) in D2O was investigated using several NMR techniques. EGCg formed a 1:1 complex with beta-CD, in which the A ring and a portion of the C ring of EGCg were included at the head of the phenolic hydroxyl group attached to C7 of EGCg in the beta-CD cavity from the wide secondary hydroxyl group side. In the 1:1 complex with beta-CD, EGCg maintained the conformation in which the B and B' rings of EGCg took pseudoequatorial and pseudoaxial positions with respect to the C ring, respectively. The structure of the inclusion complexes of beta-CD and EGCg obtained from NMR experiments supported those determined from AM1 semiempirical SCF MO calculations well.
Ishizu
Takashi
T
Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Sanzo Gakuen-cho 1, Fukuyama, Hiroshima 729-0292, Japan. ishizu@fupharm.fukuyama-u.ac.jp
Hirata
Chikako
C
Yamamoto
Hideji
H
Harano
Kazunobu
K
D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015394:Molecular Structure; D012997:Solvents; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry*
D012997:Solvents; D047392:beta-Cyclodextrins; D014867:Water; D002392:Catechin; C045651:epigallocatechin gallate; C031215:betadex