Fucoidans from brown algae Laminaria longipes and Saccharina cichorioides: Structural characteristics, anticancer and radiosensitizing activity in vitro.

• Fucoidan LlF from L. longipes was α-L-fucan with unusual structure. • LlF consisted of 1,2-, 1,3- and 1,4-linked α-L-Fuc residues. • Fucans LlF and ScF had anticancer effect on melanoma and colon cancer cells. • Fucans LlF and ScF possessed comparable radiosensitizing activity. The sulfated α- l -fucans ScF and LlF were obtained from brown algae of the Laminariaceae family (Saccharina cichorioides and Laminaria longipes). According to spectroscopy NMR, the LlF fucan predominantly contained the →3)-α- l -Fuc p- (2SO 3 –)-(1→4)-α- l -Fuc p -(1→2)-α- l -Fuc p- (4SO 3 –)-(1→ repeating units, with small amounts of disaccharide 1,4-linked fragments and 3-sulfated fucose residues. Mass spectrometric analysis revealed the presence of the following fragments in the fucan structure: α- l -Fuc p- (2SO 3 –)-(1→4)-α- l -Fuc p -(2SO 3 –)-(1→3)-α- l -Fuc p -(4SO 3 –); α- l -Fuc p- (2,4SO 3 –)-(1→3)-α- l -Fuc p -(1→3)-α- l -Fuc p- (4SO 3 –); α- l -Fuc p- (2SO 3 –)-(1→2)-α- l -Fuc p ; α- l -Fuc p- (2SO 3 –)-(1→2)-α- l -Fuc p- (4SO 3 –); α- l -Fuc p- (2SO 3 –)-(1→3)-α- l -Fuc p ; α- l -Fuc p- (2,4SO 3 –)-(1→3)-α- l -Fuc p ; α- l -Fuc p- (4SO 3 –)-(1→4)-α- l -Fuc p ; and α- l -Fuc p -(4SO 3 –)-(1→4)-α- l -Fuc p -(2SO 3 –). Both ScF and LlF fucoidans inhibited colony formation and growth of melanoma and colon cancer cells and sensitize-tested cancer cells to X-ray radiation to a comparable degree. [ABSTRACT FROM AUTHOR]