Sulfated modification and biological activities of polysaccharides derived from Zizyphus jujuba cv. Jinchangzao

Abstract

Two polysaccharides JCS-1 and JCS-2 were successfully purified by DEAE-52 Cellulose chromatography from Zizyphus jujuba cv. Jinchangzao. Their structures were analyzed by high performance liquid chromatography (HPLC), high-performance gel permeation chromatography (HPGPC), nuclear magnetic resonance (NMR), and fourier transform infrared (FT-IR) spectroscopy. Further, eight sulfated derivatives are prepared by chlorosulfonic acid-pyridine (CSA-Pyr). Structural analysis revealed that both JCS-1 and JCS-2 were size uniform polysaccharides with the average molecular weight (Mw) of 71.75 kDa and 357.39 kDa, respectively. JCS-1 mainly has galacturonic acid (GalA) composition, and also contains a small amount of galactose (Gal) and arabinose (Ara), and their molar ratio is 39.04:1.26:1.39. JCS-2 was composed of GalA, mannose (Man), rhamnose (Rha), Ara and Gal, at a molar ratio of 19.87:2.07:1.77:1.65:1.16. Activity studies indicate that both natural polysaccharides and sulfated modified polysaccharides have immunomodulatory activity, while sulfated modified polysaccharides are stronger. Moreover, the sulfated polysaccharides significantly prolonged partial thromboplastin time (APTT) and thrombin time (TT) clotting times, but did not alter prothrombin time (PT) clotting time. The degree of substitution of polysaccharides seemed to be closely related to their biological characteristics. Sulfated modification represents an effective method of enhancing the immunomodulatory and anticoagulant activities of jujuba polysaccharides.