QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Online Supplemental Material All Versions of this Article: 139/8/1469    most recent jn.109.106765v1 Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Appeldoorn, M. M. Articles by Hollman, P. C. H. PubMed PubMed Citation Articles by Appeldoorn, M. M. Articles by Hollman, P. C. H.

---

Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions

Procyanidin Dimers A1, A2, and B2 Are Absorbed without Conjugation or Methylation from the Small Intestine of Rats^1–3,

⁴ Laboratory of Food Chemistry, Wageningen University, Wageningen 6700 EV, The Netherlands; and ⁵ RIKILT-Institute of Food Safety, Wageningen 6700 AE, The Netherlands

Intervention studies with procyanidin (PC)-rich extracts and products such as cocoa and wine suggest protective effects of PC against cardiovascular diseases. However, there is no consensus on the absorption and metabolism of PC dimers. Interestingly, nothing is known about the absorption of A-type PC. In this study, the absorption and metabolism of purified PC dimers A1 [epicatechin-(2-O-7, 4–8)-catechin], A2 [epicatechin-(2-O-7, 4–8)-epicatechin], and B2 [epicatechin-(4–8)-epicatechin], A-type trimers, a mixture of A1, B2, and a tetrameric A-type, and monomeric epicatechin were compared by in situ perfusion of the small intestine of rats for 0–30 min. The rats had their bile duct, portal vein, and small intestine cannulated. Unmodified and methylated metabolites were distinguished from their conjugates by differential β-glucuronidase treatment. A1 and A2 dimers were absorbed from the small intestine of rats and they were better absorbed than dimer B2. Absorption of the A-type dimers was only 5–10% of that of monomeric epicatechin. Dimers were not conjugated or methylated in contrast to epicatechin, which was partly methylated and 100% conjugated. A-type trimers were not absorbed. Furthermore, the presence of tetrameric PC enhanced the absorption of B2 but not that of A1. Epicatechin, methylated epicatechin, and their conjugates were not found as metabolites of the PC tested. In conclusion, dimers A1, A2, and B2 are slightly absorbed but are not conjugated or methylated, thus conserving their biological activity after absorption. Because PC contents of foods are relatively high, dimers may contribute to systemic effects of PC.

^* To whom correspondence should be addressed. E-mail: peter.hollman{at}wur.nl.

Manuscript received 6 March 2009. Initial review completed 4 April 2009. Revision accepted 3 May 2009.

Published online 3 June 2009.