Novel polysaccharide and polysaccharide-peptide conjugate from Rosa rugosa Thunb. pseudofruit – Structural characterisation and nutraceutical potential

A novel bioactive polysaccharopeptide (C1) and polysaccharide (C2) with an average molecular weight of 180 kDa and 70 kDa were isolated from R. rugosa pseudofruit. The composition of the macromolecules was established using 1H NMR, FT-IR, GC–MS, SDS-PAGE coupled with enzymatic cleavage, and proteomic analyses (LC-MS). C1 was found to contain 60.56 ± 1.82 % of sugars and 21.17 ± 0.47 % of uronic acids. Its main neutral monosaccharides were arabinose, rhamnose, galactose, glucose, fucose, and mannose. C1 was found to be a polysaccharopeptide containing pectinesterase-like protein. C2 was composed of 32.85 ± 0.97 % of sugars and 48.77 ± 1.15 % of uronic acids. Its main neutral monosaccharides were galactose, glucose, rhamnose, arabinose, and mannose. A promising nutraceutical value of the polysaccharides was revealed. Assays showed strong α-glucosidase inhibitory activity of both macromolecules and considerable antiradical potential and moderate lipoxygenase inhibitory activity of the crude polysaccharide. Moreover, antiproliferative activity of C2 was observed.