Chlorogenic acids (CGA) are cinnamic acid derivatives with biological effects mostly related to their antioxidant and antiinflammatory activities. Caffeoylquinic acids (CQA) and dicaffeoylquinic acids (diCQA) are the main CGA found in nature. Because green coffee is a major source of CGA, it has been used for production of nutraceuticals. However, data on the bioavailability of CGA from green coffee in humans are inexistent. The present study evaluated the pharmacokinetic profile and apparent bioavailability of CGA in plasma and urine of 10 healthy adults for 8 h after the consumption of a decaffeinated green coffee extract containing 170 mg of CGA. Three CQA, 3 diCQA, and caffeic, ferulic, isoferulic, and p-coumaric acids were identified in plasma by HPLC-Diode Array Detector-MS after treatment. Over 30% (33.1 +/- 23.1%) of the ingested cinnamic acid moieties were recovered in plasma, including metabolites, with peak levels from 0.5 to 8 h after treatment. CGA and metabolites identified in urine after treatment were 4-CQA, 5-CQA, and sinapic, p-hydroxybenzoic, gallic, vanillic, dihydrocaffeic, caffeic, ferulic, isoferulic, and p-coumaric acids, totaling 5.5 +/- 10.6% urinary recovery of the ingested cinnamic and quinic acid moiteties. This study shows that the major CGA compounds present in green coffee are highly absorbed and metabolized in humans.

The bioavailability of chlorogenic acid, a major polyphenol of the human diet that is particularly abundant in coffee and various fruits, was explored in rats. To identify the form under which it is absorbed through the gut mucosa and the site of absorption along the gastrointestinal tract, rats were fed a diet supplemented with chlorogenic acid (0.25%, wt:wt). Chlorogenic acid and its metabolites were estimated in the stomach, small intestine and cecal contents as well as in bladder urine and plasma by HPLC with coulometric detection at several time points (1.5, 3, 4.5, and 7 h) after the beginning of the meal. Minor hydrolysis of chlorogenic acid (<1%) occurred in the stomach and small intestine contents, whereas 15-32% of ingested chlorogenic acid was hydrolyzed into caffeic acid in the cecum. Chlorogenic acid and caffeic acid appeared early (at 1.5 h) in plasma and urine, suggesting an absorption of chlorogenic acid into the upper part of the gastrointestinal tract. Gastric absorption of chlorogenic acid was further examined by infusing chlorogenic acid in the ligated stomach of food-deprived rats. After 30 min of infusion, intact chlorogenic acid was found in the gastric vein and aorta. No other metabolites could be detected by HPLC-electrospray ionization-MS-MS. These results show for the first time that chlorogenic acid is quickly absorbed in the rat stomach in its intact form.

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The absorption and metabolism in the small intestine of chlorogenic acid (5-O-caffeoylquinic acid), the main phenolic acid in the human diet, and of caffeic acid were studied in rats in order to determine whether chlorogenic acid is directly absorbed or hydrolysed in the small intestine. Chlorogenic and caffeic acids were perfused into a segment of ileum plus jejunum during 45 min (50 microm, 0.75 ml/min) using an in situ intestinal perfusion rat model with cannulation of the biliary duct, and were quantified together with their metabolites in perfusion effluent, bile and plasma. The net absorption (influent flux minus effluent flux of phenolic acids and their metabolites) accounted for 19.5 % and 8 % of the perfused caffeic and chlorogenic acids, respectively. A minor fraction of the perfused caffeic acid was metabolized in the intestinal wall and secreted back into the gut lumen in the form of ferulic acid (0.5 % of the perfused flux). Part of the chlorogenic acid (1.2 % of the perfused flux) was recovered in the gut effluent as caffeic acid, showing the presence of trace esterase activity in the gut mucosa. No chlorogenic acid was detected in either plasma or bile, and only low amounts of phenolic acids (less than 0.4 %) were secreted in the bile. The present results show that chlorogenic acid is absorbed and hydrolysed in the small intestine. In contrast to numerous flavonoids, absorbed phenolic acids are poorly excreted in the bile or gut lumen. Their bioavailability therefore appears to be governed largely by their uptake into the gut mucosa.

Cardiovascular disease (CVD) mortality rates are lower in Asian countries where dietary patterns are very different from Western diet. A number of studies have linked these lower rates to the inclusion of soy products as a staple food in those countries. Soy is the richest dietary source of isoflavones, a type of phytoestrogen associated with many potentially beneficial effects. Isoflavone-containing soy protein consumption has been linked to reduced levels of LDL cholesterol in hypercholesterolemic patients. This effect is increased with the concomitant administration of isoflavones, and seems to be also complemented by the isoflavone capacity to restore the endothelial function in patients with weak and moderated endothelial dysfunction. The effects are variable depending on individuals� � � metabolism and in particular to their ability to convert daidzein to equol that seems to be restricted to approximately 1/3 of the population. Equol production has been indeed linked to a decreased arterial stiffness and antiatherosclerotic effects via NO production. Because the relevance of isoflavones consumption on the modulation of cardiovascular risk still remains unclear, this paper aims to review the existing knowledge on the biological activity of the isoflavones on the human cardiovascular system from an epidemiological, clinical and -omics point of view.