Abstract
Population aging has increased interest in food-based strategies to support healthy aging. Phyllanthus emblica L. (P. emblica) is an edible fruit widely used in functional food products; however, the nutritional characteristics, safety, and functional differentiation of its distinct fruit parts generated during processing remain unclear. In this study, four anatomical parts of P. emblica (the whole fruit, P), juice powder (PJP), pomace (PP), and seed-containing core (PC) were systematically evaluated for nutritional composition, antioxidant activity, safety, and anti-aging potential using a D-galactose-induced aging mouse model. Results show that the P. emblica juice powder (PJP) retained the most favorable nutritional characteristics and exhibited superior antioxidant capacity. A clear efficacy gradient was observed (PJP > P > PP > PC), with PJP showing the most pronounced improvements in aging-associated functional outcomes and redox and inflammatory status. Given the role of the gut-brain axis in aging-related regulation, gut microbiota composition and short-chain fatty acids (SCFAs) production were further analyzed. PJP selectively enriched beneficial bacteria, including Akkermansia and Alistipes, and increased SCFA levels, particularly propionic acid and isovaleric acid. In contrast, the seed-containing core raised safety concerns, characterized by hepatotoxicity and elevated serum aminotransferases. Overall, this study establishes a clear hierarchy of efficacy and safety among P. emblica fruit parts and supports the rational selection of juice powder for functional food development targeting healthy aging.