In vivo comparison of the bioavailability of (+)-catechin, (-)-epicatechin and their mixture in orally administered rats.
We compared levels of (+)-catechin, (-)-epicatechin, and their metabolites in rat plasma and urine after oral administration. Rats were divided into four groups and given (+)-catechin (CA group), (-)-epicatechin (EC group), a mixture of the two (MIX group) or deionized water. Blood samples were collected before administration and at designated time intervals thereafter. Urine samples were collected 0-24 h postadministration. (+)-Catechin, (-)-epicatechin and their metabolites in plasma and urine were analyzed by HPLC-mass spectrometry after treatment with beta-glucuronidase and/or sulfatase. After administration, absorbed (+)-catechin and (-)-epicatechin were mainly present in plasma as metabolites, such as nonmethylated or 3'-O-methylated conjugates. In the CA and MIX groups, the primary metabolite of (+)-catechin in plasma was glucuronide in the nonmethylated form. In the EC and MIX groups, in contrast, the primary metabolites of (-)-epicatechin in plasma were glucuronide and sulfoglucuronide in nonmethylated forms, and sulfate in the 3'-O-methylated forms. Urinary excretion of the total amount of (-)-epicatechin metabolites in the EC group was significantly higher than the amount of (+)-catechin metabolites in the CA group. The sum of (+)-catechin metabolites in the urine was significantly lower in the MIX group than in the CA group, and the sum of (-)-epicatechin metabolites in the MIX group was also significantly lower than in the EC group. These results suggest that the bioavailability of (-)-epicatechin is higher than that of (+)-catechin in rats, and that, in combination, (+)-catechin and (-)-epicatechin might be absorbed competitively in the gastrointestinal tract of rats.
Baba
S
S
Functional Foods R&D Laboratories, Meiji Seika Kaisha, Ltd., Sakado 350-0289, Japan. seigo_baba@meiji.co.jp
Osakabe
N
N
Natsume
M
M
Muto
Y
Y
Takizawa
T
T
Terao
J
J
D000284:Administration, Oral; D000818:Animals; D019540:Area Under Curve; D001682:Biological Availability; D002392:Catechin / Q000378:metabolism / Q000493:pharmacokinetics* / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D007408:Intestinal Absorption; D008297:Male; D008745:Methylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013237:Stereoisomerism
D002392:Catechin