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 sidechains. Sulphation with SO3-pyridine gave a product with DS 0.40. According to 13C 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.