Structural characteristics and inhibition of tumor cell growth in vitro of enzymatically and chemically extracted fucoidans from Saccharina latissima

Fucoidans are bioactive sulfated polysaccharides present in the cell walls of brown algae offering diverse health benefits. In this study, fucoidans from the brown alga Saccharina latissima were extracted using a green enzyme-assisted extraction technique and a mild acid extraction procedure, respectively, to compare their structural features and potential anticancer activities. The purified fucoidan fractions from the enzyme-assisted extraction were designated SlF2 and SlF3, and those from the mild chemical extraction were SlChF2 and SlChF3. SEC analysis revealed that the molecular weights of fucoidans from the enzyme-assisted extraction were significantly higher than those from the chemical extraction. Monosaccharide composition and NMR analysis indicated that fucoidan fractions were mixtures of sulfated fucans and galactofucans while SlChF3 mainly consisted of sulfated fucans. The potential inhibition of cancer cell growth in vitro of the fucoidans from S. latissima was investigated: All four fucoidan fractions were non-toxic to the small intestine adenocarcinoma cell line HuTu-80 and the human malignant melanoma cell line RPMI-7951. Interestingly, all four fucoidan fractions inhibited the growth of HuTu-80 cells, while only fractions SlF3 and SlChF3 were effective against RPMI-7951 cells at rates of 26% and 32%, respectively. These findings highlight the potential of S. latissima fucoidans as promising anticancer agents, and underlines the importance of the extraction method for attaining bioactive fucoidan molecules.