Urolithins: microbial biosynthesis, metabolic pathways and health benefits for functional food and cosmeceutical applications.

UNLABELLED: The gut microbiota profoundly influences host health by producing bioactive metabolites from dietary substrates. Among these, urolithins derived from ellagitannins in pomegranates, nuts and berries have attracted major scientific interest. Urolithin A (UroA), in particular, is noted for enhancing mitochondrial function through mitophagy, alongside its anti-inflammatory, antioxidant and anticancer activities. Structurally, urolithins share a tricyclic lactone backbone, with variations in hydroxylation accounting for their diversity. Their bioavailability and physiological effects, however, depend on factors such as gastrointestinal pH, solubility and the individual's gut microbiota composition. This review explores the origins, microbial metabolic pathways, chemical structures and biological activities of urolithins, emphasizing their therapeutic potential in metabolic, neurodegenerative and dermatological health. Furthermore, it highlights the roles of microbial enzymes and biosynthetic routes, offering perspectives on strategies to optimize urolithin production and application in functional foods, pharmaceuticals and cosmeceuticals. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-026-02136-6.