Exploring the effects of phenolic compounds to reduce intestinal damage and improve the intestinal barrier integrity: A systematic review of in vivo animal studies

Background & aims: The integrity of the intestinal barrier in the diseased is key to prevent further complications and disease such as sepsis and death, whereas, the role of food bioactive molecules (i. e. phenolic compounds (PCs) on the intestinal barrier, is still unknown. The current aim was to explore the benefits of the oral PC administration on the intestinal barrier integrity in animals. Methods: The effects of PCs on the intestinal barrier integrity in in vivo animal models of intestinal inflammation were assessed up-to August 2020 from the PubMed, SCOPUS, and Cochrane Library da-tabases under the PRISMA methodology. The risk of bias was assessed from ARRAY and SCYRCLE tools. Results: From 1241 articles, 14 studies were included. In animals, oral resveratrol (n = 6) improves the intestinal barrier integrity and reduces intestinal damage. Additionally, grape seed extract (n = 2), cur-cumin (n = 1), genistein (n = 1), chlorogenic acid (n = 1), grape pomace (n = 1), olive leaf (n = 1) or cranberry extract (n = 1) improve the intestinal barrier integrity downregulating various inflammatory molecules (TNF-alpha, and other interleukins), and increasing the antioxidant enzymes in animals. Furthermore, resveratrol, quercetin, epigallocatechin, and other PCs improve the epithelial barrier integrity and pro-inflammatory molecule expression in the intestinal epithelia. Conclusions: The oral PC administration in animals improves the intestinal barrier integrity and function from three main mechanisms: 1) The reduction of pro-inflammatory molecules, 2) the improvement in tight-junction protein expression, and 3) the improvement of the antioxidant intracellular activity suggesting the potential use of PCs in the management of intestinal injury in humans, particularly for resveratrol, the most studied PC. (c) 2020 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Oral administration of phenolic compounds improves intestinal barrier integrity in animals by reducing inflammatory molecules, enhancing tight-junction protein expression, and boosting antioxidant activity.