Isolation, purification, structural characterization, and antitumor activity of Gynura divaricata polysaccharides

In this study, a water-soluble, homogeneous polysaccharide, GDPs-1, was isolated from Gynura divaricata and purified. It was subsequently subjected to structural characterization and biological activity assessment. Structural characterization revealed that GDPs-1 was mainly composed of glucose, galactose, and arabinose, with a molecular weight of 55.1 kDa. Its main structural backbone was →[4)-α-D-Glcp-(1]₂₂ → 4)-α-D-Glcp-(1 → 4)-α-D-Glcp-(1 → [4)-β-D-Galp-(1]₁₁→, with two additional branched structures. In vitro experiments demonstrated that GDPs-1 induced cancer cell apoptosis, caused cell cycle blockade, increased the Bax/Bcl-2 protein ratio, attenuated epithelial-mesenchymal transition, and activated caspase-3 protein in carcinoma cells, thereby exerting antitumor effects on tumor cells without affecting the growth of normal cells. Therefore, GDPs-1 may be further explored as a novel medicine to treat lung and liver cancer.