urolitin

Urolitin is a name given to a group of phenolic metabolites produced in the human gut from ellagitannins, a class of polyphenols found in certain fruits and nuts. The best studied members are urolitin A and urolitin B, with others such as C and D described less extensively. These compounds are typically formed when gut microbiota metabolize ellagic acid derived from ellagitannins, including punicalagin from pomegranate and ellagitannins in berries and nuts. There is substantial interindividual variation in urolitin production, leading to distinct urolitin metabotypes that influence the amount and type of metabolites generated.

In humans and animal models, urolitins are investigated for their antioxidant and anti-inflammatory properties, as well as potential effects on cellular pathways related to cancer and aging. A notable area of interest is urolitin A’s ability to induce mitophagy, a process that helps maintain mitochondrial quality, which could have implications for age-related decline in muscle and metabolic function. However, the evidence from human studies remains preliminary, with small sample sizes and mixed results, and findings from animal studies do not always translate to clinical benefits.

Pharmacokinetics and safety data are limited. Urolitins are absorbed mainly as conjugates (such as glucuronides and sulfates) and are excreted in urine and feces. They are not approved as medicines; they appear in some dietary supplements as metabolites of ellagitannins, but product contents can vary.

Research continues to clarify the human relevance of urolitins, their health effects, and potential therapeutic applications, particularly in aging and metabolic health.