An active heparinoid obtained by sulphation of a galactomannan extracted from the endosperm of Senna macranthera seeds

A galactomannan was isolated from the endosperm of seeds of Senna macranthera. It contained mannose and galactose in a 3.0:1 ratio and consisted mainly of a (1 -->4)-linked beta -D-Manp main-chain partially substituted at O-6 with alpha -D-Galp side-chains. Sulphation with SO3-pyridine gave a product with DS 0.40. According to C-13 NMR analysis, the OH-6 groups of galactopyranosyl and mannopyranosyl units were preferentially substituted. The product had 45 IU/mg of anticoagulant activity, as shown by the in vitro activated partial thromboplastin time (APTT), compared with 183 IU/mg for a porcine intestinal mucosa heparin. Two fractions of the sulphated derivative were obtained differing in their affinity to AT III in gel. Only that with a high affinity (DS 1.4) showed a strong anticoagulant activity, as measured by APTT (321 IU/ mg) and Heptest. By analogy with heparin, the anticoagulant activity of the derivative could be expressed through binding of the polysaccharide to AT III. (C) 2001 Elsevier Science Ltd. All rights reserved.