Extraction of Bioactive Compounds from Stems of Undaria pinnatifida

Stems of brown seaweed Undaria pinnatifida are not often used because they are too difficult to masticate. This study used conventional liquid solvent extraction methods and supercritical carbon dioxide (SC-CO2) fluid extraction to investigate the yields of various bioactive compounds in Undaria pinnatifida stems. The enzymatic (α-amylase and glucoamylase) inhibitor activities of the extracts were also examined. The SC-CO2 with ethanol extraction produced high amounts of phenolic and flavonoid compounds, fucoxanthin, epicatechin, and gallic acid. Also, the extracts obtained by SC-CO2 with ethanol exhibited the most potent inhibitor of α-amylase and glucoamylase among all the extracts studied, perhaps because of the high content of fucoxanthin. These results suggest that stems of Undaria pinnatifida could have value as a raw material to extract these bioactive substances.