Mangrove Resilience in the Gulf: Phytochemical Insights into Avicennia marina Under Extreme Environmental Conditions

Mangroves are salt-tolerant woody plants that grow in intertidal regions. Avicennia marina is the dominant mangrove species along the Gulf Coast, where it contributes significantly to the health and biodiversity of aquatic ecosystems. Increasing pressures from climate change make the resilience of A. marina crucial to sustainable environmental management. A. marina shows remarkable resilience to extreme environmental conditions, and this ability has led researchers to study its phytochemical profile and therapeutic potential. However, in the Gulf, where it faces high temperature and high salinity waters, studies on the phytochemistry of this species are limited. Since the chemical composition of plants is influenced by geographical, environmental and climatic conditions, A. marina could produce unique secondary metabolites to cope with these stresses. This study aimed to analyse the phytochemical profile of the leaves, roots, and seeds of A. marina. Samples collected from the Al Zorah mangrove forest were extracted with a hydroalcoholic solution and qualitative analyses of the extracts were performed by electrospray ionisation-coupled liquid chromatography and high-resolution mass spectrometry. The molecules identified, some never before characterised in mangroves, include flavonoids, iridoid glycosides, and triterpene saponins. These molecules aid A. marina's response to abiotic stresses such as salinity fluctuations, high temperatures, and high UV radiation. Furthermore, from a bioprospecting perspective, the plant extracts were tested for antioxidant and anti-cancer activity, with the root extracts showing the most promising results. This highlights the need to preserve these mangroves, also because of their role as a source of promising natural compounds. By extending this phytochemical work to the analysis of differences between healthy and stressed mangroves, potential stress indicators can be identified. This knowledge would be very valuable for practical applications in plant management and conservation strategies, directly contributing to the resilience and health of aquatic ecosystems in the context of climate change.