Structural determination and pro-angiogenic effect of polysaccharide from the pollen of Typha angustifolia L

Four fractions of polysaccharides (TPP-1, TPP-2, TPP-3, and TPP-4) were isolated and purified from the pollen of Typha angustifolia L., and the structure of TPP-3 was furtherly determined by HPGPC (High Performance Gel Permeation Chromatography), monosaccharide composition analysis, methylation analysis and NMR (Nuclear Magnetic Resonance). TPP-3 was found to be a homogeneous heteropolysaccharide with an average molecular weight of 5.5 × 10⁴ Da and composed of eight types of monosaccharides. The pro-angiogenic activities of TPP-3 were verified on HUVECs and VEGFR tyrosine kinase inhibitor II (VRI)-induced vascular defect zebrafish model. Furthermore, the underlying mechanism investigation showed that its pro-angiogenic activities were closely related with the activation of VEGF/PI3K/Akt signaling pathway.