- Ulvan is a unique, water-soluble sulfated polysaccharide extracted mainly from the cell walls of green macroalgae belonging to the genus Ulva (commonly known as sea lettuce).
- It is one of the principal structural components of these algae, accounting for 8–29% of their dry weight, depending on the species and environmental conditions. Structurally, ulvan is highly complex and heterogeneous, composed of repeating disaccharide units containing rhamnose, xylose, glucuronic acid, iduronic acid, and significant amounts of sulfate groups. Its backbone contains unusual sugar residues such as sulfated rhamnose and uronic acids, which are rare in terrestrial plant polysaccharides, giving ulvan distinctive physicochemical and biological properties.
- In the algal cell wall, ulvan contributes to mechanical strength, hydration, and protection against environmental stressors such as salinity, desiccation, and microbial attack. Its sulfate groups play a key role in ion exchange and water retention, helping algae adapt to fluctuating marine environments. Because of its structural similarity to glycosaminoglycans (GAGs) found in animal connective tissues, ulvan has drawn considerable interest for biomedical applications. This resemblance is particularly evident in its uronic acid and sulfate content, which mimic features of chondroitin sulfate and heparan sulfate.
- From a biological and health perspective, ulvan has been investigated for a wide range of bioactivities. In vitro and in vivo studies have demonstrated antioxidant, anticoagulant, antiviral, antibacterial, immunomodulatory, and antitumor properties. Its anticoagulant activity, though weaker than that of heparin, suggests potential as a natural blood-thinning agent with fewer side effects. The prebiotic potential of ulvan has also been explored, as it can be fermented by gut microbiota, leading to the production of short-chain fatty acids (SCFAs) that promote intestinal and systemic health. Moreover, ulvan and its oligosaccharides may stimulate immune responses, positioning them as promising nutraceuticals.
- In food and nutraceutical industries, ulvan is valued as a dietary fiber and functional ingredient. Its ability to form gels, films, and emulsions has applications as a thickener, stabilizer, and edible coating. As interest in seaweed-derived ingredients grows, ulvan offers a sustainable source of bioactive polysaccharides for functional foods and supplements aimed at cardiovascular, digestive, and immune health. Additionally, its biocompatibility and biodegradability make it attractive for inclusion in vegan and sustainable food formulations.
- Beyond nutrition, ulvan has significant pharmaceutical, biomedical, and industrial applications. In drug delivery, its sulfate groups and gel-forming ability make it suitable for controlled release systems and bioactive compound encapsulation. In tissue engineering, ulvan-based hydrogels and scaffolds are being investigated for cartilage and bone regeneration, owing to their GAG-like structure. In agriculture, ulvan has been studied as a biostimulant that can enhance plant growth and stress tolerance. Environmentally, ulvan extracted from seaweed biomass offers potential for developing biodegradable films, coatings, and packaging materials, contributing to sustainable alternatives to plastics.
