Abstract: The polysaccharides components of Olong tea were isolated and purified with DEAE-52 cellulose column chromatography. Sulfation, acetylation and carboxymethylation modification were separately selected to study on anticoagulant function in vitro of purified tea polysaccharides. The results showed that tea polysaccharides possess anticoagulant function, which could effectively prolonged APTT of human plasma, but had no obvious effect on PT and TT. Four polysaccharide components were separated by column, the component Ⅱ occupied 57.36% of total tea polysaccharides and it was relatively high anticoagulant activity. The anticoagulant function of tea polysaccharides component Ⅱ was further enhanced by sulfation,acetylation and carboxymethylation modification. The proportion between chemical modification reagents and polysaccharides, and modificating reaction time influenced on the modification degree of molecular structure of tea polysaccharides, and changed the anticoagulant activity accordingly.

Key words: tea polysaccharides, chemical modification, anticoagulant