Structure and antitumor activity of a polysaccharide from Rosa roxburghii

It is well known that Rosa roxburghii, as a homology of both medicine and food, is rich in polysaccharides. To discover bioactive macromolecules for combating cancer, the polysaccharides in R. roxburghii were investigated, leading to the purification of a polysaccharide (RRTP80-1). RRTP80-1 was measured to have an average molecular weight of 8.65 × 10³ g/mol. Monosaccharide composition analysis revealed that RRTP80-1 was formed from three types of monosaccharides including arabinose, glucose, and galactose. Methylation and GC-MS analysis suggested that the backbone of RRTP80-1 consisted of →5)-α-l-Araf-(1→, →6)-α-d-Glcp-(1→, →2,5)-α-l-Araf-(1→, →4,6)-β-d-Galp-(1→, and →3)-α-l-Araf-(1→, with branch chains composed of α-l-Araf-(1→. In vivo studies indicated that RRTP80-1 exhibited inhibitory activity against the growth and proliferation of neoplasms in the zebrafish tumor xenograft model by suppressing angiogenesis. Additionally, RRTP80-1 was found to upregulate reactive oxygen species (ROS) and nitric oxide (NO) production levels in zebrafish models. All these studies suggest that RRTP80-1 activates the immune system to inhibit tumors. The potential role of the newly discovered homogeneous polysaccharide RRTP80-1 in cancer treatment was preliminarily clarified in this study.