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Albumin stabilizes (–)‐epigallocatechin gallate in human serum: Binding capacity and antioxidant property
Author(s) -
Bae MinJung,
Ishii Takeshi,
Minoda Kanako,
Kawada Yukiko,
Ichikawa Tatsuya,
Mori Taiki,
Kamihira Miya,
Nakayama Tsutomu
Publication year - 2009
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.200800274
Subject(s) - human serum albumin , chemistry , epigallocatechin gallate , gallate , antioxidant , serum albumin , biochemistry , bovine serum albumin , incubation , polyphenol , nuclear chemistry
(–)‐Epigallocatechin gallate (EGCg) is the major component of green tea and is known to show strong biological activity, although it can be easily oxidized under physiological conditions. In this study, we indicate that EGCg is stable in human serum and that human serum albumin (HSA) stabilizes EGCg under aerobic condition. Although EGCg is usually decomposed within 1 h in aqueous solution at neutral pH, EGCg in serum and phosphate buffer (pH 7.4) containing HSA was stable over 1 h, even at neutral and slightly alkaline pH. Under these conditions, EGCg binds to HSA non‐covalently. The sulfhydryl group acts as an antioxidant for EGCg oxidation. Incubation of EGCg with HSA is accompanied by the oxidation of a free sulfhydryl group in HSA. These results suggest that the antioxidant property and the binding capacity of HSA contribute to the stabilization of EGCg in human serum.