The Fate of trans-Caftaric Acid Administered into the Rat Stomach

Abstract

trans-Caftaric acid is the most abundant nonflavonoid phenolic compound in grapes and wines. It occurs in chicory and is one of the bioactive components of Echinacea purpurea. In order to fill the gap of knowledge about its bioavailability in mammals, we investigated its absorption, tissue distribution, and metabolism in rats. Assuming that the stomach is a relevant site of absorption of dietary polyphenols, a solution of trans-caftaric acid was maintained in the ligated stomach of anaesthetized rats for 20 min. Intact trans-caftaric acid was detected in rat plasma at both 10 and 20 min (293 +/- 45 and 334 +/- 49 ng/mL, respectively), along with its O-methylated derivative trans-fertaric acid, whose concentration rose over time (from 92 +/- 12 to 185 +/- 24 ng/mL). At 20 min, both trans-caftaric acid and trans-fertaric acid were detected in the kidney (443 +/- 78 and 2506 +/- 514 ng/g, respectively) but not in the liver. Only trans-fertaric acid was found in the urine (33.3 +/- 12.8 microg/mL). In some rats, trans-caftaric acid was detected in the brain (180 +/- 20 ng/g).

The Evolution of Polyphenols from Grapes to Wines

“…Caftaric and fertaric acids exist in their trans form, mainly localized in the grape pulp and, during the grape pressing, being quickly released into the juice, while a negligible fraction of the cis isomer has been found for p-coutaric acid. Contrary to this, the trans and cis isomers of p-coutaric acid are less extractable since they are mostly localized in the grape skin, being partially responsible for the astringent properties of both grapes and wines [14]. Although the white wines have a lower concentration of phenolic compounds compared to the red ones, they contain, in turn, a high quantity of caftaric acid.…”

“…Although the white wines have a lower concentration of phenolic compounds compared to the red ones, they contain, in turn, a high quantity of caftaric acid. Hydroxycinnamic acids and their tartaric esters constitute the main class of nonflavonoid phenolics in red wines and the main class of phenolic compounds in white wines [14]. During the fermentation process, these esters are partially hydrolyzed, resulting free hydroxycinnamic acids, transformed then into ethyl coumarate and ethyl caffeate [15].…”

Bioavailability of phenolic acids

“…1), ester of caffeic acid and tartaric acid, only absorption from the stomach and microbial metabolism were studied. It appeared that it was absorbed from the stomach, and was found under its intact form and under transfertaric acid form in the plasma, excreted in urine only under trans-fertaric acid form (Vanzo et al 2007). Incubation with active faecal flora showed that in the caecum, caftaric acid could be metabolized in two main metabolites, 3-hydroxyphenylpropionic and benzoic acids (Gonthier et al 2006).…”

Echinacea increases arginase activity and has anti-inflammatory properties in RAW 264.7 macrophage cells, indicative of alternative macrophage activation

“…Pharmacokinetic studies demonstrate that natural or synthesized caffeic acid derivatives (e.g. caftaric acid, chlorogenic acid and echinacoside) are quickly absorbed in the rat stomach, but rapidly eliminated from circulation (Jia et al, 2006; Lafay et al, 2006; Vanzo et al, 2007). Matthias et al (2004) suggests a low bioavailability for caffeic acid derivatives of Echinacea based on their poor permeability through Caco-2 monolayers, a model for the intestinal epithelial barrier.…”