Marine Algae: A rich reservoir of bioactive compounds with nutritional and therapeutic potential

Marine algae represent an abundant and renewable biological resource with growing relevance in the fields of health and biomedicine due to their capacity to produce structurally diverse bioactive compounds. Both microalgae and macroalgae, including representatives of the red (Rhodophyta), green (Chlorophyta), and brown (Phaeophyta) algal groups, generate metabolites that support their ecological survival while also exhibiting notable pharmacological properties. This review consolidates current research findings across four major categories of biological activity: anti-inflammatory, antioxidant, anti-obesity, and anticoagulant effects. Polysaccharides such as fucoidans isolated from brown algae (e.g., Undaria pinnatifida and Macrocystis pyrifera), along with extracts derived from red algae (Kappaphycus alvarezii) and green algae (Ulva pertusa), have demonstrated significant immunomodulatory and enzyme-inhibitory activities. In addition, marine algae are important sources of antioxidant molecules, including polyphenols, carotenoids, and sulfated polysaccharides, identified in species such as Callophyllis japonica, Gracilaria tenuistipitata, Ulva lactuca, and Ulva reticulata. Certain algal metabolites—such as fucoxanthin, siphonoxanthin, and phlorotannin—exert anti-obesity effects through multiple metabolic pathways, while sulfated galactans and fucans provide promising alternatives to conventional anticoagulants. Beyond their bioactive potential, marine algae also offer a comprehensive nutritional profile, reinforcing their value as functional foods and as sources of biomedical compounds.