Structural Studies

Polysaccharides of Algae: 60. Fucoidan from the Pacific Brown Alga Analipus Japonicus (Harv.) Winne (Ectocarpales, Scytosiphonaceae)

M. I. Bilan1, A. N. Zakharova1, A. A. Grachev1, A. S. Shashkov1, N. E. Nifantiev1 and A. I. Usov1#

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1Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninskii pr. 47, Moscow, 119991, Russia

Received: April 16, 2006; in final form: May 30, 2006

Abstract. A fucoidan containing L-fucose, sulfate, and O-acetyl groups at a molar ratio 3:2:1, as well as minor amounts of xylose, galactose, and uronic acids was isolated from the brown alga Analipus japonicus collected in the Sea of Japan. The structures of the native polysaccharide and the products of its desulfation and deacetylation were studied by the methods of methylation, periodate oxidation, and NMR spectroscopy. It was shown that a polysaccharide molecule mainly consists of a linear carbohydrate chain of (1→3)-linked α-L-fucopyranose residues, which bears numerous branches in the form of single α-L-fucopyranose residues (three branches at position 4 and one branch at position 2 per each ten residues of the main chain). Sulfate groups occupy positions 2 and (to a lesser extent) 4, most of the terminal nonreducing fucose residues being sulfated twice. The acetyl groups are located predominantly at positions 4. The structural role of minor monosaccharides was not established.

Key words: Analipus japonicus, brown algae, fucoidan, NMR spectroscopy, sulfated polysaccharides

Russian Journal of Bioorganic Chemistry 2007, 33 (1): 38-46