Protection of Lipids from Oxidation by Epicatechin, trans-Resveratrol, and Gallic and Caffeic Acids in Intestinal Model Systems

• Published in: Journal of agricultural and food chemistry Vol. 54; no. 26; pp. 10288 - 10293
• Main Authors: Kerem, Zohar, Chetrit, David, Shoseyov, Oded, Regev-Shoshani, Gilly
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 27.12.2006
• Subjects: Animals; antioxidant activity; Antioxidants - pharmacology; Biological and medical sciences; Body Fluids - chemistry; caffeic acid; Caffeic Acids - pharmacology; Catechin - pharmacology; epicatechin; Food industries; Fundamental and applied biological sciences. Psychology; gallic acid; Gallic Acid - pharmacology; gastric juice; in vitro studies; intestinal fluid; Intestines - metabolism; linoleic acid; Linoleic Acids; Lipid Peroxidation - drug effects; Male; Models, Biological; oxidation; Rats; Rats, Sprague-Dawley; resveratrol; small intestine; Stilbenes - pharmacology; Flavanol; Gallic acid; Phenolic acid; Digestive system; Lipids; Partition coefficient; Gastrointestinal tract; Antioxidant; Gastrointestinal; Flavonoid; Caffeic acid; Polyphenol; Resveratrol; Phenols; dietary antioxidants; Models; Oxidation protection; phenolics
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf0621828

Consumption of polyphenols is associated with health promotion through diet, although many are poorly absorbed in animals and humans alike. Lipid peroxides may reach the intestine and initiate deleterious oxidation. Here we measured inhibition of the oxidation of linoleic acid (LA) in authentic fluid from rat small intestine (RIF) by two dietary polyphenols, a flavonoid, epicatechin (EC), and a stilbene, resveratrol (RV), and by gallic (GA) and caffeic (CA) acids, and their partition coefficients. Both polyphenols inhibited 80%, and CA inhibited 65%, of the production of hexanal. GA was the weakest antioxidant in this assay. Interestingly, measuring peroxides production in RIF showed that only epicatechin inhibited the first stage of oxidation. The oxidizing agent, the antioxidant comound, the solution pH and lipophilicity are known to affect the total antioxidative activity. We suggest that the mechanism of this activity changes in accord with the environment:  i.e., RV may act as a free radial scavenger, but here, in protecting lipids in intestinal fluid from oxidation, it acts as a hydrogen atom donor. Since the concentration of phenolics is much higher in the intestinal fluid than is ever achieved in plasma or other body tissues, it is suggested that their antioxidant activity could be exerted in the gastrointestinal tract (GIT), breaking the propagation of lipid peroxides oxidation and production of toxic compounds. Keywords: Gastrointestinal tract; dietary antioxidants; phenolics; partition coefficient