title: Binding affinity of tea catechins for HSA: characterization by high-performance affinity chromatography with immobilized albumin column.
abstract: Catechins are the major polyphenols in green tea leaves. Recent studies have suggested that the catechins form complexes with HSA for transport in human blood, and their binding affinity for albumin is believed to modulate their bioavailability. In this study, the binding affinities of catechins and their analogs were evaluated and the relationship between the chemical structure of each catechin and its binding property were investigated. Comparing these catechins by HPLC analysis with the HSA column, we showed that galloylated catechins have higher binding affinities with HSA than non-galloylated catechins. In addition, pyrogallol-type catechins have a high affinity compared to catechol-type catechins. Furthermore, the binding affinity of the catechin with 2,3-trans structure was higher than those of the catechin with 2,3-cis structure. The importance of the hydroxyl group on the galloyl group and B-ring was confirmed using methylated catechins. These results indicate that the most important structural element contributing to HSA binding of tea catechins is the galloyl group, followed by the number of hydroxyl groups on the B-ring and the galloyl group or the configuration at C-2. Our findings provide fundamental information on the relationship between the chemical structure of tea catechins and its biological activity.
authors.affiliation: Department of Food and Nutritional Sciences, and Global COE Program, University of Shizuoka, 52-1 Yada, Suruga-ku Shizuoka, Japan. ishii_t@u-shizuoka-ken.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ishii
authors.forename: Kanako
authors.initials: K
authors.lastname: Minoda
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Bae
authors.forename: Taiki
authors.initials: T
authors.lastname: Mori
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Uekusa
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Aihara
authors.forename: Takumi
authors.initials: T
authors.lastname: Furuta
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Wakimoto
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kan
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakayama
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000378:metabolism; D002846:Chromatography, Affinity; D006801:Humans; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D012709:Serum Albumin; D002392:Catechin; C062669:epicatechin gallate; C045651:epigallocatechin gallate; C057580:gallocatechol