Polyphenols of the Mediterranean Diet and Their Metabolites in the Prevention of Colorectal Cancer

Abstract

The Mediterranean diet is a central element of a healthy lifestyle, where polyphenols play a key role due to their anti-oxidant properties, and for some of them, as nutripharmacological compounds capable of preventing a number of diseases, including cancer. Due to the high prevalence of intestinal cancer (ranking second in causing morbidity and mortality), this review is focused on the beneficial effects of selected dietary phytophenols, largely present in Mediterranean cooking: apigenin, curcumin, epigallocatechin gallate, quercetin-rutine, and resveratrol. The role of the Mediterranean diet in the prevention of colorectal cancer and future perspectives are discussed in terms of food polyphenol content, the effectiveness, the plasma level, and the importance of other factors, such as the polyphenol metabolites and the influence of the microbiome. Perspectives are discussed in terms of microbiome-dependency of the brain-second brain axis. The emergence of polyphenol formulations may strengthen the efficiency of the Mediterranean diet in the prevention of cancer.

Mechanisms Mediating the Regulation of Peroxisomal Fatty Acid Beta-Oxidation by PPARα

“…Resveratrol, or 3,4 ,5-trihydroxystilbene, is a natural polyphenol present in large amounts in Japanese knotweed (Polygonum cuspidatum) root. This phytoalexin is produced by a wide variety of plants, some of which are edible for humans, such as grapes, blackberries, blackcurrants, blueberries, and cranberries, to name but a few [224]. However, in the last two decades, the effect of resveratrol on animal models related to several disorders, such as autism spectrum disorder, mitochondrial myopathies, type 2 diabetic nephropathy, or renal lipotoxicity has been increasingly reported.…”

“…Quercetin (2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one) is a flavonoid polyphenol found in plants and a variety of other natural sources-red grape, onion, broccoli, tomatoes and lettuce [224]. PPARα is significantly upregulated and enhances β-oxidation by mulberry-leaf powder containing quercetin [230].…”

“…Epigallocatechin-3-gallate (EGCG) is catechin conjugated with gallic acid. It belongs to the flavonol class and is found abundantly in green tea [232] and cocoa, which have the highest content of catechins, followed by prune juice, broad bean pods, and argan oil [224].…”

“…Curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-hepta-1,6-diene-3,5-dione) belongs to a chemical class of polyphenols that is extracted from the rhizomes of the turmeric plant (Curcuma longa) [224]. Tetrahydro-curcumin improves oleic acid-induced hepatic steatosis and ameliorates insulin resistance in HepG2 cells, likely through downregulation of the expression of the lipogenic proteins, SREBP-1c and PPARγ, and the stimulation of lipolysis by upregulating PPARα and CPT-1a, which are involved in fatty acid β-oxidation [235].…”

New Mechanisms of Action of Natural Antioxidants in Health and Disease II

“…Natural antioxidants such as polyphenols demonstrate low bioavailability because of different factors: interaction with the food matrix, intestine uptake, microbiota interaction, and endogenous transformation by phase I and phase II metabolism [ 16 ]. On the other hand, many of the activities exerted by natural antioxidants may be mediated by their metabolites, which are produced in vivo [ 17 , 18 ].…”