Phytochemical Diversity of Punica granatum L. and Its Multi-Target Biological Functions

L. is a nutritionally relevant fruit with a complex phytochemical profile that varies across its anatomical fractions, including peel, arils, juice, seeds, and seed oil. Although pomegranate is widely recognized for its health-promoting potential, the nutritional significance of its matrix-dependent composition, bioavailability, and gut microbiota-mediated metabolism remains insufficiently integrated. This review aimed to critically evaluate the phytochemical diversity of pomegranate and its nutrition-related multi-target biological functions, with particular emphasis on food matrices, bioaccessibility, and translational relevance. A structured review of peer-reviewed studies indexed in major scientific databases from 2000 to January 2026 was conducted. Eligible reports included analytical, preclinical, and clinical studies addressing the composition of pomegranate-derived materials and their biological effects, with attention to extraction matrix, processing, bioavailability, microbial biotransformation, and mechanisms of action. Pomegranate exhibits marked matrix-specific phytochemical diversity. Peel is particularly rich in ellagitannins, especially punicalagin and punicalin; arils and juices are enriched in anthocyanins and flavonols; and seed oil contains high levels of punicic acid. Reported biological activities include antioxidant, anti-inflammatory, antimicrobial, metabolic, anti-aging, and anticancer effects. These actions appear to result from synergistic interactions among multiple bioactive compounds rather than from a single dominant constituent. Importantly, gut microbiota-driven conversion of ellagitannins and ellagic acid into urolithins is a major determinant of systemic bioactivity and may contribute to interindividual variability in response. The health effects of pomegranate should be interpreted within a nutrition-focused, matrix-dependent framework integrating composition, processing, bioavailability, and microbiota-derived metabolism.