Chemical characterization of acetyl fucoidan and alginate from commercially cultured Cladosiphon okamuranus

An acetyl fucoidan was isolated from Cladosiphon okamuranus which is commer cially cultured, at 18,500 t/year off Okinawa Islands, Japan. The yield of acetyl fucoidan was 2.3% (W/W/) based on the wet algae. The total carbohydr ates, D-glucuronic acid, sulphuric acid, ash, and moisture of the fucoidan was 69.0%, 13.5%, 13.6%, 23.0%, and 3.2%, respectively. The L-fucose, D-xyl ose and D-glucuronic acid residues were identified by liquid chromatography . The infrared spectrum and optical rotation of the fucoidan was in agreeme nt with that of standard fucoidan (Sigma Co., Ltd.). The acetyl residue was identified by H-1-NMR and C-13-NMR spectroscopy, respectively. The molar r atio of the sugar residues of the acetyl fucoidan was estimated to be L-fuc ose:D-xylose; D-glucuronic acid: acetic acid: sulfuric acid, 4.0:0.03:1.0:2 .0:2.0. An alginate was also isolated from Cladosiphon okamuranus. The yield of the alginate was estimated as 0.1% (W/W) based on the wet algae. The total car bohydrate, uronic acid, ash, and moisture of the alginate was 87.6%, 87.9%, 10.0%, and 2.3%, respectively. The infrared spectrum and optical rotation of the alginate was in agreement with that of standard alginate. The D-mann uronic acid and L-guluronic acid were identified by H-1- and C-13-NMR spect roscopy, the molar ratio of both sugar residues was estimated to be 0.20.1. 00. The acetyl fucoidan could be produced simply from artificially cultured Cladosiphon okamuranus.