Green Extraction of Bioactive Compounds from Marine Macroalgae: Chemistry, Pharmacological Activities, and Biotechnological Applications

Did you know that Asia produces 97% of the world's seaweed—and that these humble marine plants are packed with compounds that could revolutionize medicine?

Marine macroalgae, or seaweeds, are more than just ocean floor decoration. They are renewable resources with enormous economic and environmental potential. This review dives into three major phyla—Chlorophyta, Heterokontophyta, and Rhodophyta—highlighting both breakthroughs and persistent hurdles. The numbers are striking: Asia dominates global production with 97%, and China leads the pack. But the real treasure lies within these organisms' cells. Seaweeds synthesize a dazzling array of bioactive compounds, from sulfated polysaccharides and phlorotannins to terpenoids, proteins, peptides, and pigments. Notably, brown algae are the richest source of both phlorotannins and polyunsaturated fatty acids. To unlock these compounds, scientists are turning to green extraction techniques like enzyme-assisted, microwave-assisted, and ultrasound-assisted methods, as well as supercritical fluid extraction and natural deep eutectic solvents. These approaches consistently outperform conventional methods in yield, speed, and environmental friendliness. The extracted compounds show validated pharmacological activities—immunomodulatory, anti-inflammatory, anti-diabetic, neuroprotective, antitumor, and antiviral—making them valuable for functional foods, biomedicine, cosmetics, agriculture, and beyond. Yet challenges remain: understanding structure–activity relationships, scaling up sustainable extraction, and moving toward clinical use. Future research will focus on discovering new bioactives, producing oligosaccharides enzymatically, purifying algal proteins, and scaling up industrial processes. The ocean's green gold is just beginning to reveal its potential.

Key Points

• Asia produces 97% of global seaweed; China dominates.
• Brown algae richest in phlorotannins and polyunsaturated fatty acids.
• Green extraction methods outperform conventional approaches in yield and sustainability.