title: Size exclusion chromatographic analysis of polyphenol-serum albumin complexes.
abstract: Formation of water-soluble polyphenol-protein complexes was investigated by size-exclusion chromatography (SEC). The combination of (-)-epigallocatechin gallate (EGCG) and bovine serum albumin (BSA), which did not form a precipitate after the solutions were mixed, showed an SEC peak due to complex formation 2-24 h after mixing. Peak size of the complex varied with time, suggesting slow change of the conformation of the protein accompanied by complexation. Formation of the complex was substantiated by ultrafiltration of the mixture; the complex did not pass through a membrane with a 100,000 nominal molecular weight limit (NMWL). The SEC profile varied with the combination of compounds. The peaks due to the complexes showed that the apparent value of the number average molecular weight (M(n)) of the EGCG-BSA complex was 2.8x10(5), while that of a pentagalloylglucose (PGG)-BSA complex was 9.5x10(5) under the conditions used. Dimeric hydrolyzable tannins, oenothein B and cornusiin A, also caused changes in the SEC profile of BSA, although the combinations did not show peaks attributable to formation of such large complexes observed for EGCG and PGG. Procyanidin B3 and (+)-catechin did not cause changes in the SEC profile of BSA. With cytochrome c, EGCG did not show any chromatographic changes.
authors.affiliation: Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama 700-8530, Japan. hatano@pharm.okayama-u.ac.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hatano
authors.forename: Mami
authors.initials: M
authors.lastname: Hori
authors.forename: Richard W
authors.initials: RW
authors.lastname: Hemingway
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshida
mesh_terms: D044946:Biflavonoids; D002392:Catechin; D002850:Chromatography, Gel / Q000379:methods*; D005419:Flavonoids / Q000737:chemistry*; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry*; D059808:Polyphenols; D044945:Proanthocyanidins; D012709:Serum Albumin / Q000737:chemistry*
chemical_list: D044946:Biflavonoids; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D044945:Proanthocyanidins; D012709:Serum Albumin; C479581:procyanidin B3; D002392:Catechin