Phytochemical Composition and Antioxidant Activities of Sonneratia caseolaris (L.) Engl. Leaves and Roots: Insights Into a Promising Mangrove Species

Mangroves thrive in extreme environments and produce secondary metabolites with significant pharmacological potential, making them a rich reservoir of bioactive natural products for the development of new therapeutic agents. Sonneratia caseolaris (mangrove apple) has long been utilized in traditional medicine for its antioxidant, antimicrobial, and antifungal activities, although comprehensive investigations of its phytochemistry and biological activities remain limited. In this context, the present study provides the first comprehensive profiling of the chemical constituents and antioxidant capacity of S. caseolaris leaves and roots collected in the Maldives. Ethanol 50% extracts of leaves and roots were analyzed using ultraperformance liquid chromatography-electrospray ionization-high resolution mass spectrometry (UPLC-ESI/HRMS) operated in positive and negative ionization modes and antioxidant potential was evaluated by spectrophotometric ABTS, DPPH, and ORAC assays. A total of 45 molecules were detected, predominantly polyphenols, including phenolic acids, flavonoids, and tannins. Flavonoid glycosides and gallotannins were the major groups, with several compounds not previously documented in this species or among mangroves. Both extracts exhibited strong antioxidant responses, yielding IC50 values comparable to or lower than ascorbic acid. These findings expand the phytochemical knowledge of S. caseolaris, underscore its antioxidant activity and highlight its pharmacological and nutraceutical potential.