Phlorotannins have gained significant attention as functional supplements because of their potential bioactive and functional properties. Phlorotannins are, however, highly sensitive to gastrointestinal digestion, which limits their bioavailability and, consequently, their in vivo efficacy. This study addressed such limitation by resorting to cyclodextins as extraction-assisting hosts. Various concentrations of γ- and β-cyclodextrins were tested in combination with the aqueous microwave-assisted extraction of phlorotannins from Fucus vesiculosus (bladderwrack seaweed), evaluating yields and stability of the extracts using an in vitro gastrointestinal digestion protocol. The increase of cyclodextrin concentrations resulted in increasing extraction yields, up to 8% more.
An important finding in this work is that β- and γ-CDs, when used for assisted extraction at high doses (15 × and 30 ×), markedly improved phlorotannin stability across the different stages of gastrointestinal digestion. Specifically, β-CD exhibited the highest protective effect, preventing phlorotannin degradation almost completely in both oral and gastric phases, and retaining approximately 35% of the initial content at the end of the intestinal phase. In another experiment, β-CD was mixed with the extracts a posteriori; this method turned out to be less effective, because post-extraction addition of β-CD demonstrated weaker capacity to prevent gastrointestinal degradation of phlorotannins in our tests.
The take-home message of this study is that the use of β-CD during microwave-assisted aqueous extraction offers a clear improvement in resistance and residence time of phlorotannins in the intestinal lumen, opening way for applications in nutrition and wellbeing.
Sofia F. Reis, Marcelo D. Catarino, Susana S. Braga, Manuel A. Coimbra, Artur M. S. Silva, Susana M. Cardoso (2026) Improving in vitro Gastrointestinal Stability of Phlorotannins From Food Grade Fucus vesiculosus Extracts Using Cyclodextrins. Journal of Food Science 91:e70830
https://doi.org/10.1111/1750-3841.70830