Chemical characterization of fucoidan from commercially cultured Nemacystus decipiens (Itomozuku)

Fucoidan was isolated from Nemacystus decipiens KUCKUCK which is commercial ly cultured at the rate of about 2,000 t/year in fields of the Okinawa Isla nds, in Japan. The yield of fucoidan extracted by 0.1 M HCl was 0.5% (W/W) based on the wet algae, The total carbohydrate, sulfuric acid, ash, and moi sture in fucoidan was 65.8, 30.8, 22.3, and 3.8%, respectively. Fucose and galactose were identified by liquid chromatography. The molar ratio of the sugar residues in the fucoidan was estimated to be L-fucose:D-galactose:sul furic acid = 1.0:0.05:1.0. The optical rotation of the fucoidan (0.4%) show ed a value of -0.315 degrees at 60 degrees C, then it decreased a little wi th decreasing temperature. The infrared spectrum of isolated fucoidan is in agreement with that of standard fucoidan. The molecular mass of fucoidan w as estimated to be 2.4 x 10(5). The H-1- and C-13-NMR spectral data suggest that fucoidan is mainly composed of L-fucopyranose, 2-mono-O-sulfo-L-fucop yranose, 4-mono-O-sulfo-L-fucopyranose, and 2,4-di-O-sulfo-L-fucopyranose.