The Metabolic Fate of Apple Polyphenols in Humans

Gastrointestinal absorption and metabolism of apple polyphenols ex vivo by the pig intestinal mucosa in the Ussing chamber

“…During gastrointestinal passage, they undergo extensive metabo-lism similar to that shown for other compounds, such as epigallocatechin-3-O-gallate [5]. Free hydroxycinnamic acids and its esters with D-(-)-quinic acid, free aglyca of the ingested flavonoids, as well as glucuronides, sulfates, and other derivatives, such as methylated compounds, can be found in ileal fluid, plasma, and urine after the consumption of apple products [6]. For example, after the consumption of 1 L of cloudy apple juice, less than 1 to 80 µM of the ingested polyphenols were determined in the ileostomy effluents of volunteers, representing the amounts reaching the colon in healthy subjects [7,8].…”

Apple as a Source of Dietary Phytonutrients: Bioavailability and Evidence of Protective Effects against Human Cardiovascular Disease

“…DuPont et al [33] have also determined the uptake and excretion of low doses of polyphenols in six subjects who each consumed 1.1 L of an alcoholic cider beverage. No quercetin was found in urine or plasma, but 3'-methyl quercetin was detected in plasma suggesting that low doses of quercetin are extensively methylated in humans [28] [33].…”

“…This implies they have either not been absorbed through the gut barrier, absorbed and excreted in the bile or metabolized by the colonic microflora or our own tissues. Only very rare measurements of the intestinal absorption of polyphenols in humans are available [14] [27] [28]. Large uncertainties remain due to the lack of comprehensive data on the content of some of the main polyphenol classes in food.…”

Aryl Azide Based, Photochemical Patterning of Cyclic Olefin Copolymer Surfaces with Non‐Biofouling Poly[(3‐(methacryloylamino)propyl)dimethyl(3‐sulfopropyl)ammonium hydroxide]

“…During gastrointestinal passage, they undergo extensive metabolism similar to that shown for other compounds, such as epigallocatechin‐3‐ O ‐gallate [5]. Free hydroxycinnamic acids and its esters with D ‐(–)‐quinic acid, free aglyca of the ingested flavonoids, as well as glucuronides, sulfates, and other derivatives, such as methylated compounds, can be found in ileal fluid, plasma, and urine after the consumption of apple products [6]. For example, after the consumption of 1 L of cloudy apple juice, less than 1 to 80 μM of the ingested polyphenols were determined in the ileostomy effluents of volunteers, representing the amounts reaching the colon in healthy subjects [7, 8].…”