Abstract
Procyanidins are important biologically active compounds, but the pathway and extent of absorption and metabolism are controversial. We conducted a mass balance study to evaluate the total radioactivity excreted in urine and feces after oral administration of [14C]procyanidin B2 to male rats (n = 5). Urine and feces were collected daily from 0 to 96 h. Absolute bioavailability of 14C from [14C]procyanidin B2 was calculated as ∼82% using the values for total urinary 14C. A pharmacokinetic study measured total radioactivity in the blood (n = 9). Blood samples were collected at designated time intervals (0.5–24 h) after administration. Three treatments were used: 1) intravenous, 2) oral higher dose (21 mg/kg b.wt.), and 3) oral lower dose (10.5 mg/kg). Blood concentration of total 14C reached a maximum at ∼6 h after ingestion of [14C]procyanidin B2 (groups II and III), and area under the curve (AUC) was dependent on oral dose. After intravenous or oral administration the terminal half-lives were similar, whereas 8-fold larger values were obtained after oral dosing for total clearance and the apparent volumes of distribution. These pharmacokinetic differences explain the apparently lower 14C bioavailability (8–11%) for [14C]procyanidin calculated from blood [AUC(0–24)] values. After oral administration of [14C]procyanidin B2, 63% was excreted via urine within 4 days. The data suggest that much of the parent compound administered orally is degraded by the gut microflora before absorption and that these microbial metabolites have a different distribution from the compounds circulating after the intravenous dose.
Footnotes
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This work was funded by the European Union 6th framework project FLAVO.
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Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
doi:10.1124/dmd.109.030304
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- Clp
- total clearance
- Vd
- apparent volumes of distribution
- AUC
- area under the curve.
- Received September 19, 2009.
- Accepted November 5, 2009.
- Copyright © 2010 by The American Society for Pharmacology and Experimental Therapeutics
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