Anti-HIV activity of sulfonated arabinofuranan and xylofuranan

In order to elucidate the relationship between the structure and anti-HIV activity of sulfonated polysaccharides, two anhydro-pentose monomers having different configurations of substituents at C2 and C3 positions from D-ribose, 1,4-anhydro-2,3-di-O-tert-butyldimethylsilyl-alpha -L-arabinofuranose and -D-xylofuranose, were polymerized, respectively, with PFS catalyst to give (1 --> 5)-alpha -L-arabinofuranan and (1 --> 5)-alpha -D-xylofuranan derivatives. After deprotection and subsequent sulfonation, sulfonated arabinofuranan and xylofuranan having Various molecular weights and degree of sulfonation were obtained. Commercially available xylan ((1 --> 4)-beta -D-xylopyranan) Was also sulfonated to give sulfonated xylan. These sulfonated pentosans having higher degrees of sulfonation of 1.4-1.9 (maximum, 2) were found to have potent anti-HIV activities in the EC50 of 0.1-0.6 mug/ml which were as high as those of sulfonated ribofuranans and ribopyranans reported previously, suggesting that the sulfonated pentofuranan-type polysaccharides having a high degree of sulfonation had potent anti-HIV activity. In addition, the sulfonated arabinofuranan and xylofuranan had higher blood anticoagulant activities, 36 and 28 unit/mg, respectively, than those of sulfonated xylan with six-membered pentopyranosidic unit, 14-15 unit/mg, suggesting that the flexible furanan-type backbone structure worked effectively in the high activity. (C) 2001 Elsevier Science Ltd. All rights reserved.