Structural analysis and biological effects of a neutral polysaccharide from the fruits of Rosa laevigata

A neutral water-soluble polysaccharide (RLP50-2) was extracted and purified from the fruits of Rosa laevigata. The absolute molecular weight was determined as 1.26 × 10⁴ g/mol. Monosaccharide composition analysis showed that RLP50-2 mainly consisted of glucose, arabinose, and galactose. Structural analysis revealed that RLP50-2 consisted of →5)-α-L-Araf-(1→, →2,5)-α-L-Araf-(1→, →3,5)-α-L-Araf-(1→, →4)-α-D-Glcp-(1→, →6)-α-D-Glcp-(1→, →3,6)-β-D-Glcp-(1→, →4)-α-D-Galp-(1→, →6)-β-D-Galp-(1→, →2)-β-D-Xylp-(1→, terminal α-L-arabinose, and terminal β-D-mannose. Biological assays showed that RLP50-2 had immunomodulatory activities using cell and zebrafish models. Moreover, RLP50-2 showed significantly antitumor activities by inhibiting tumor cell proliferation and migration and blocking angiogenesis. These results suggested that RLP50-2 could be developed as a potential immunomodulatory agent or antitumor candidate drug in biomedicine field.