Bioactive Compounds in Marine Algae

Marine algae encompass a vast assemblage of brown, red and green seaweeds that synthesise structurally diverse bioactive metabolites. Key families include sulphated polysaccharides such as fucoidan, carrageenan and ulvan, whose degrees of sulphation and molecular weight govern antioxidant, anticoagulant, immunomodulatory and antiviral effects. Phenolic polymers known as phlorotannins in brown algae exhibit potent free-radical scavenging and antimicrobial activity, while halogenated terpenoids, alkaloids and fatty acids provide additional antimicrobial, anti-inflammatory and anticancer potential. Pigments such as chlorophylls and carotenoids contribute both to photoprotection and bioactivity, and lectins offer targeted binding to cell-surface carbohydrates. Extraction and purification techniques—from enzymatic digestion to subcritical water methods—play a decisive role in preserving structural motifs that underpin biological function. The global significance of these compounds spans nutraceuticals, functional foods, pharmaceuticals, cosmetics and biomaterials. Advances in structure-function analysis are elucidating precise modes of action and guiding sustainable harvesting and biorefinery processes to unlock the full potential of marine algae in health and industry.

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Bioactive Compounds in Marine Algae publication trend

The graph below shows the total number of articles in bioactive compounds in marine algae across all publications each year (not limited to Nature Index journals).

Technical terms

Fucoidan: A sulphated fucose-rich polysaccharide found predominantly in brown macroalgae, noted for antioxidant, anticoagulant and immunomodulatory properties.

Carrageenan: A group of sulphated galactans extracted from red algae, used as gelling agents and recognised for antiviral and antitumour effects.

Ulvan: A sulphated heteropolysaccharide from green algae, exhibiting immunomodulatory and antioxidant activities linked to its rhamnose-rich backbone.

Phlorotannins: Polyphenolic compounds unique to brown algae, formed by polymerisation of phloroglucinol units, with strong free-radical scavenging and antimicrobial effects.

Subcritical water extraction: A process utilising pressurised water at elevated temperatures below its critical point to solubilise and recover heat-stable bioactive compounds efficiently.

References

1. Marine fucoidans: Structural, extraction, biological activities and their applications in the food industry. Food Hydrocolloids (2023).
2. Alkaline subcritical water extraction of bioactive compounds and antioxidants from beach-cast brown algae (Ascophyllum Nodosum). Chemical Engineering Journal (2024).
3. Biological Activities of Fucoidan and the Factors Mediating Its Therapeutic Effects: A Review of Recent Studies. Marine Drugs (2019).
4. Fucoidans from brown seaweeds: an update on structures, extraction techniques and use of enzymes as tools for structural elucidation. RSC Advances (2013).