Purification, characterization and biological activities in vitro of polysaccharides extracted from tea seeds

Three polysaccharide fractions (NTSPS, ATSPS1-1 and ATSPS2) were isolated and purified from the water extract of tea (Camellia sinensis) seeds with yields of 32.74%, 25.22%, and 11.09%, respectively. The average molecular weight of NTSPS, ATSPS1-1 and ATSPS2 was determined by HPGPC system, with an Mw of 4.588, 500 and 100 kDa, respectively. Monosaccharide analysis by ion chromatography revealed they differed from each other in monosaccharide kinds and molar ratio. Furthermore, ATSPS1-1 and ATSPS2 were heteropolysaccharide bounded with protein (2.83% and 2.12%) and 17 general amino acids were detected in them on an ion-chromatographic analyzer. The IR spectrum of ATSPS1-1 and ATSPS2 revealed the typical characteristics of polysaccharides and protein. In addition, the antitumor and immunological activity of the three polysaccharide fractions in vitro were also evaluated. It was found inhibition activity of NTSPS, ATSPS1-1 and ATSPS2 on K562 cells increased with increasing sample concentration and the inhibition ratios of them at 400 μg/mL were beyond 30.13 ± 3.54%, 36.61 ± 2.75% and 32.33 ± 2.53%, respectively. They also exhibited strong ability in promoting proliferation of mice splenic lymphocyte. Results of these studies indicated the three purified polysaccharides had a potential application as natural antitumor drugs.