Food Ellagitannins: Structure, Metabolomic Fate, and Biological Properties

Abstract

Food sources of ellagitannins (ETs) are numerous, and dietary intake of these compounds is estimated up to 12 mg/day in some countries, even though ETs have been considered in the past as not bioavailable like other tannins and were mostly neglected by nutritionists. Nonetheless, new insights show that ETs are bioconverted by microbiota in the gut into metabolites called urolithins, which are bioavailable and can reach relatively high physiological concentration in the body up to 7 days after ingestion. According to the initial structure of ETs in the food source, the extent of bioconversion into urolithins may differ but all urolithins are susceptible to exert potential health benefits. Nonetheless, due to the intervention of microbiota, the production and excretion of urolithins are highly variable according to individuals, which have led to the classification of consumers into metabotype. According to metabotype, the potential health benefits of ellagitannins may differ among consumers. In in vitro, cellular and animal studies, numerous health benefits of ellagitannins and urolithins are reported mainly for the chemoprevention of hormone-dependent cancer and cardiovascular disease. Nonetheless, ellagitannins deserve closer attention from the scientific community to unravel more biological properties of this particular compound.

Pomegranate peel extract protects against the development of diabetic cardiomyopathy in rats by inhibiting pyroptosis and downregulating LncRNA-MALAT1

“…In our study, punicalagin, pedunculagin, valoneic acid dilactone, HHDPG, and ellagic acid are the ellagitannins detected, whereas cyanidin-3- O -glucoside and delphinidin-3- O -glucoside were the major anthocyanins. Ellagitannins are metabolized to ellagic acid and then to urolithin compounds, which are considered responsible for the biological activities of ellagitannins ( Villalba et al, 2019 ). Punicalagin demonstrated a cardioprotective effect in diabetic conditions where it significantly decreased elevated cTn-1 to normal levels, attenuated IL-1b, IL-6, and TNF-α, and ameliorated the lipid profile in a streptozotocin-induced diabetic model ( El-Missiry et al, 2015 ).…”

Urolithins and Their Precursors Ellagic Acid and Ellagitannins: Natural Sources, Extraction and Methods for Their Determination

“…More than 1000 ETs have been detected to occur in many plants; nevertheless, few of them are fit for human consumption. Fruits including strawberries, berries, pomegranate, and nuts and seeds are rich in edible ETs, within which raspberries and cloudberries are the most abundant sources, as are processed foods, including fruit-derived beverages, jams and cakes (Table 1) [1,3,17]. In general, fruits of the genus Rubus are the most studied for their content in ETs and EA.…”

“…Therefore, obviously, the rational use of these by-products may lead the pharmaceutical, nutraceutical and cosmetic industries to the development of valuable products for human health. Furthermore, many scientific papers discuss various plant species for their significant amount in ETs and EA [1][2][3]17]. Plant families, such as Myrtaceae, Rosaceae, Asteraceae and Fagaceae, are reported to include several plant genera, which produce ETs and EA [33,34].…”

A Review of the Dietary Intake, Bioavailability and Health Benefits of Ellagic Acid (EA) with a Primary Focus on Its Anti-Cancer Properties

“…Studies have shown that urolithins are much more readily bioavailable and appear in human systemic circulation within a few hours of pomegranate ingestion reaching maximum concentrations between 24 and 48 hours. They were found to exist in both free and conjugated forms in the plasma and urine [ 8 , 9 ]. In view of this they are considered the bioactive forms of ETs.…”