| The extraction, purification and partical characterization of polysaccharides for leaves of Taxus mairei were studied. The structural analysis of the polysaccharides also been examined. The crude polysaccharids were extracted from leaves of Taxus with hot water. To establish the optimum extraction conditions, three factors in extraction were optimized, i.e. solid:liquid ration, extraction temperature and alcohol concentration according to orthogonal design. The results showed that the optimum condition to extraction is temperature is 100℃, solid:liquid ration is 1:10 alcohol concentration is 90%. For the further research, the polysaccharides should be decolonized. De-coloration of the polysaccharides with activated carbon ion exchange resin and absorption resin was studied. The effects of amount of activated carbon, pH and temperature on decoloration were also investigated. The optimum condition is pH5.0, 7% of activated carbon and 20℃. Anion exchange resin A500p and absorption resin XAD7HP represented good colorizing ability. Decolorizing experiments were carried out by considering the impact of absorption time,pH and temperature. The best conditions for decoloration were determined as follows:t=3hr,pH=6.4 and T=20℃. The absorption accords with Freundlich isotherm and the key process of mass transfer is in liquid membrane.Crude polysaccharides were fractionated by DEAE-Sepharose FF under the condition as the following: pH is 8.5, HCl-Tris buffer, NaCl elute. Three kinds of polysaccharides named PTM-1, PTM-2 and PTM-3 were got by DEAE-Sepharose FF ion exchanger. After purified by Sephacryl S-300 and desalted by Sephardex G-25, PTM-3 is a homogeneous pure polysaccharide confirmed by UV-spectrometer and gel permeation chromatograph, its average molecular weight (Mw) measured by gel permeation chromatograph is 12.3kD. PTM-3 is composed of Gal GlcVA Rha and Ara which was verified by TLC. PTM-3 is linked by β-(l, 3) linkage proved by infrared spectroscopy.
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