Abstract: Optimization of the extraction of polysaccharide from Tanyang Congou black tea for higher polysaccharide yield was carried out using one-factor-at-a-time method and response surface methodology. The optimal conditions that provided maximum polysaccharide yield (10.52%) were found as follows: temperature, 60 ℃; extraction time, 70 min; and solvent-to-solid ratio, 30:1 (mL/g). The purified polysaccharide (76% purity) contained uronic acid and pyranose rings, and consisted of arabinose (34%), galacturonic acid (30%), glucose (14%), galactose (13%), fucose (5%), and rhamnose (4%). Furthermore, the polysaccharide showed a remarkable inhibitory effect on the growth of solid tumors in H22-bearing BALB/c mice and protected spleen and thymus against tumor damage. These results provide an experimental basis for the extraction and antitumor activity evaluation of polysaccharide from black tea.

Key words: black tea polysaccharide, extraction, antitumor activity