Structural characterization and anti-tumor activity in vitro of a water-soluble polysaccharide from dark brick tea

Recently, more and more attention has been paid to the structure and application of tea polysaccharides. Herein, a water-soluble homogeneous polysaccharide (DTP-1) from dark brick tea was purified, characterized, and investigated its anti-tumor activity in vitro. The DTP-1 with a molecular weight of 11,805 Da is mainly composed of glucose, galactose and arabinose. It has a backbone, which is composed of →4)-α-D-Glcp-(1→, →5)-α-L-Araf-(1→, →6)-β-D-Galp-(1→, →2)-α-L-Araf-(1→, →3)-β-D-Galp-(1→, with →4,6)-β-D-Galp-(1 → as branching point and →1)-β-D-Glcp as terminal. In addition, DTP-1 could significantly affect the viability of A549 and SMMC7721 cells with an inhibition rate of 31.71% and 33.38% (600 μg/mL, 24 h), respectively, by inducing apoptosis and inhibiting cell migration. Moreover, DTP-1 had no effect on corresponding normal cells. Therefore, DTP-1 showed great potential to become a functional food and an anti-tumor drug. •A novel water-soluble tea polysaccharide (DTP-1) was isolated from dark brick tea.•Structure features of DTP-1 were comprehensively elucidated.•DTP-1 possess inhibiting effect on A549 and SMMC7721 cells in vitro.•DTP-1 induced cancer cells apoptosis, and blocked their proliferation and migration.•DTP-1 has great potential as a low-toxicity anti-tumor drug candidate and dietary supplement.