Contrasting Coastal Environments Are Associated With Ecotype-Specific Leaf Polyphenolic Profiles and Bioactivity in Corema album subsp. album.

Corema album subsp. album is an endemic coastal shrub adapted to the harsh Mediterranean-Atlantic interface, where populations experience strong microclimatic variation. Understanding how such environmental pressures contribute to shaping its metabolic profiles is key to supporting conservation and sustainable valorization strategies based on the responsible use of renewable plant biomass, while reducing pressure on wild populations. This study compared the phytochemical composition and bioactivities of leaf extracts from two ecotypes collected in southern Portugal. Leaves were selected as a renewable and understudied organ with antioxidant and pharmacological potential. Both ecotypes were rich in (poly)phenols, mainly flavonoids, along with phenolic acids, triterpenoids, and representatives of coumarin and anthraquinone, and exhibited strong antioxidant capacity. The Vila Real de Santo António ecotype (CL1), exposed to higher solar radiation and drought, accumulated more total (poly)phenolics, hydroxycinnamic acids, and flavonoids, displaying stronger copper-chelating and cytotoxic activities. Conversely, the Aljezur ecotype (CL2), from a cooler and more humid habitat, was richer in flavonols, hydroxybenzoic acids, and organic acids, supporting efficient redox-based antioxidant protection with lower cytotoxicity. These ecotypic differences reveal adaptive metabolic strategies that enhance stress resilience, highlighting C. album leaves as a promising renewable source of bioactive compounds for functional and sustainable health applications.