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

Abstract

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-Fucp-(2SO₃-)-(1→4)-α-l-Fucp-(1→2)-α-l-Fucp-(4SO₃-)-(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-Fucp-(2SO₃-)-(1→4)-α-l-Fucp-(2SO₃-)-(1→3)-α-l-Fucp-(4SO₃-); α-l-Fucp-(2,4SO₃-)-(1→3)-α-l-Fucp-(1→3)-α-l-Fucp-(4SO₃-); α-l-Fucp-(2SO₃-)-(1→2)-α-l-Fucp; α-l-Fucp-(2SO₃-)-(1→2)-α-l-Fucp-(4SO₃-); α-l-Fucp-(2SO₃-)-(1→3)-α-l-Fucp; α-l-Fucp-(2,4SO₃-)-(1→3)-α-l-Fucp; α-l-Fucp-(4SO₃-)-(1→4)-α-l-Fucp; and α-l-Fucp-(4SO₃-)-(1→4)-α-l-Fucp-(2SO₃-). 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.

Keywords: Anticancer activity; Fucoidan; Laminaria; Radiosensitizing effect; Saccharina.