Structure, anti-cancer properties, and potential mechanism of a biological active polysaccharide from Platycodon grandiflorum

Polysaccharides serve as a source of energy for organisms and play a crucial role in various life activities, exhibiting a wide array of biological functions. To develop bioactive polysaccharides for combating cancer, PGP40-2B, a homogeneous polysaccharide with a molecular weight of 7.05 × 103 g/mol, has been isolated from Platycodon grandiflorum, which is a traditional medicinal and edible plant with multiple functions. PGP40-2B was found to be mainly formed from several fragments including →2)-α-l-Araf-(1→, →5)-α-l-Araf-(1→, →3,4)-α-l-Rhap-(1→, →4)-α-d-GalpA-(1→, →6)-α-d-Glcp-(1→, and α-d-Galp-(1→. In addition to the structural characteristics characterized by various techniques, PGP40-2B was biologically assessed using zebrafish models and was found to exhibit in vivo antitumor effects. Subsequent mechanism studies suggested that the antitumor activity in vivo of PGP40-2B was not caused by cytotoxic mechanisms but was related to its targeting of vascular endothelial growth factor (VEGF) and programmed cell death protein 1 (PD-1) to inhibit angiogenesis and activate immunity. [Display omitted]