Preparation and Biological Activities of Sulfated Derivatives of (1.RAR.3)-.BETA.-D-Glucans.

Abstract

Sulfated derivatives of (1----3)-beta-D-glucans with different degree of branching (DB) i.e., curdlan (linear, DB 0), grifolan (6-O-substituted by beta-D-glucose at every third residue of the main chain, DB 1/3), and SSG (6-O-substituted by beta-D-glucose at every second residue, DB 1/2) having DS value (degree of substitution) lower than 0.6 were prepared. Biological activities [clotting of plasma, alternative pathway of complement (APC), proliferative response of murine spleen cells (mitogenic activity), and activation of murine peritoneal macrophages in vitro] of these derivatives were examined. Clotting of plasma was inhibited by the derivatives having DS above 0.2 APC was inhibited by incubation with derivatives and was strongly dependent on substitution. Inhibition of APC was the most significant in sulfated SSG having DS 0.6 [SSG(3)]. Mitogenic activity was observed by most of the derivatives and the highest activity was shown by SSG(1) (DS 0.2). Macrophage was also activated but SSG(1) would lose the capability to recognize the receptor for (1----3)-beta-D-glucans. From these results, it appears that the biological activities of (1----3)-beta-D-glucans were significantly modulated by sulfation and the effect was dependent on both DS and DB.