COMPARISON OF THE ANTICOAGULANT ACTION OF SULFATED AND PHOSPHORYLATEDPOLYSACCHARIDES

Oat spelts xylan (OSX), fucoidan, kappa carrageenan and chondroitin su lfates A and C were sulfated using chlorosulfonic acid-pyridine comple x while the first three were phosphorylated using methane sulfonic aci d-phosphorous pentoxide mixture. The compounds were isolated as the so dium salts and their in vitro anticoagulant properties were determined by measuring the concentration of each compound required to double pr othrombin time of pooled normal human plasma. The results of P-31-nmr spectroscopy showed that phosphorylation significantly increased the m olecular weights of the polysaccharides by forming phosphodiester and diphosphodiester bonds. In general the anticoagulant properties of the sulfated polysaccharides were related to the % sulfate while the phos phorylated polysaccharides showed increases in anticoagulant propertie s which were related to the increase in the molecular weight and inver sely related to the % phosphate. The mechanism of action of oat spelts xylan phosphate (OSXP) was studied using I-125-thrombin and normal hu man plasma. The results showed that at lower concentration of the OSXP , the complexation of I-125-thrombin with heparin cofactor-II(HC-II) w as enhanced, while at higher concentration of the compound, the comple xation with both antithrombin-III(AT-In) and HC-II was enhanced. (C) 1 997 Elsevier Science Ltd.