title: [Study of stereochemical structures of complex of tea catechins and caffeine].
abstract: Two crystals of a complex of (-)-gallocatechin-3-O-gallate (GCg) with caffeine and crystals of the complexes of (+)-catechin (CA) and (-)-catechin-3-O-gallate (Cg) with caffeine were prepared, and their stereochemical structures and intermolecular interactions were determined in X-ray crystallographic analysis. GCg formed 1:2 and 2:2 complexes with caffeine, and π-π interactions formed between the aromatic rings of GCg and caffeine in both complexes. In addition, CA of nongalloylated catechins formed a 1:1 complex with caffeine through intermolecular hydrogen bonds, whereas Cg of galloylated catechins formed a 1:2 complex with caffeine, which was formed by face-to-face and offset π-π interactions and intermolecular hydrogen bonds.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima, Japan. tsutsumi@fupharm.fukuyama-u.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsutsumi
mesh_terms: D002110:Caffeine / Q000032:analysis / Q000737:chemistry*; D002392:Catechin / Q000032:analysis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D013662:Tea / Q000737:chemistry*
chemical_list: D013662:Tea; D002110:Caffeine; D002392:Catechin