Purification, characterization and in vitro anticoagulant activity of polysaccharides from Gentiana scabra Bunge roots.

Three water-soluble polysaccharide fractions (GSP-1, GSP-2 and GSP-3) were obtained from Gentiana scabra Bunge roots by DEAE-Sepharose CL-6B and Sepharose CL-6B column chromatography. Their chemical characterizations were determined by high performance gel permeation chromatography (HPGPC), high performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD) and Fourier transform infrared (FT-IR) spectrometer. Moreover, their in vitro anticoagulant activities were evaluated by activated partial thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT) assays. GSP-1 and GSP-2 were composed of rhamnose, arabinose, galactose, glucose and galacturonic acid, while GSP-3 consisted of rhamnose, arabinose, galactose and galacturonic acid with a weight-average molecular weight of 5.8×10(4)Da. In comparison with the control group (saline), GSP, GSP-1, GSP-2 and GSP-3 could prolong APTT and TT, but not PT. Overall, GSP-3 exhibited potent anticoagulant activity and would be expected to be a potential source of anticoagulant.

Purification, characterization and anticoagulant activity of the polysaccharides from green tea.

The crude tea polysaccharides were extracted from the leaves of Camellia sinensis using deionized water. The tea polysaccharides (TPS) were further separated and purified by anion exchange chromatograph on DEAE sepharose CL-6B column to afford TPS-1, TPS-2, TPS-3 and TPS-4. The high performance gel permeation chromatograph analysis showed that the average molecular weight of polysaccharides (TPS-1, TPS-2 and TPS-3) were 20,760, 24,230 and 250,643, respectively. TPS-4 was 689, 113 and 4150, suggesting it was heterogeneous. Monosaccharide analysis detected fucose, glucosamine, rhamnose, arabinose, galactosamine, galactose, glucose, xylose, mannose, ribose, galacturonic acid and glucuronic acid in the four polysaccharide fractions. Anticoagulant activities in vitro tests showed TPS-4 could significantly prolong APTT and TT, but not PT. The result indicated TPS-4 in the regulation of coagulation initiated via the intrinsic pathway. With current findings TPS-4 should be explored as a natural potential anticoagulant.

Infrared and Raman spectroscopic characterization of structural changes in albumin, globulin, glutelin, and prolamin during rice aging.

Structural changes in albumin, globulin, glutelin, and prolamin from fresh and aged rice were characterized in this study. Infrared and Raman spectroscopies revealed changes in interactions between protein and starch, and the occurrence of structural changes involving secondary and tertiary structures of protein induced by rice aging. The α-helical structure was reduced, and aliphatic amino-acid side chains became more buried in albumin after rice aging. Oxidation of the sulfhydryl group in globulin was evident. The unordered coil in glutelin decreased, and a characteristic frequency of the free sulfhydryl group appeared. The antiparallel ß-sheet in prolamin increased, the conformation of disulfide bonds changed, and tyrosine residues became exposed to a polar environment. The association between globulin and starch strengthened, whereas that between glutelin and starch diminished. These differences in structure and interactions with starch might be responsible for the dissimilar pasting properties between fresh and aged rice.