Comparative Study on the Structural Characterization and Biological Activity of Polysaccharides from the Rosa rugosa Thunb. and Its Residues

In order to achieve the efficient utilization of Rose rugosa resources, this article took Rose rugosa and its residues after the production of rose essential oil as the research object, aimed to explore whether the rose residue retained the original bioactive ingredients of Rose rugosa. Rose rugosa polysaccharides (RP) and Rose rugosa residue polysaccharides (RRP) were obtained through extraction and purification using water extraction and ethanol precipitation, macroporous adsorption resin, and anion exchange column chromatography. The structures and biological activities of the polysaccharides were comparatively studied. The results showed that both RP and RRP contained one neutral and two acidic polysaccharide fractions. The contents of neutral sugar, uronic acid, and protein in the different polysaccharides ranged from 12.25% to 41.75%, 19.63% to 66.21%, and 1.01% to 33.84%, respectively. RP and RRP were composed of different molar ratios of rhamnose, arabinose, xylose, mannose, glucose, and galactose. The molecular weight detection results showed that RP-Ⅱ and RRP-Ⅱ had higher purity, with molecular weights of 15.47 kDa and 9.61 kDa, respectively. Scanning electron microscopy and Congo red staining revealed different surface morphologies and conformational structure of the polysaccharides. The biological activity results showed that both RP and RRP had certain antioxidant activity, among which RP-Ⅰ had a strong ability to scavenge 1,1-diphenyl-2-trinitrophenylhydrazine free radicals with a half inhibition concentration (IC₅₀) of 9.59×10⁻² mg/mL; RP-Ⅱ and RP-Ⅲ had strong hydroxyl radical scavenging abilities, with IC₅₀ values of 1.11 and 1.35 mg/mL, respectively. Meanwhile, all polysaccharides could promote the proliferation of macrophages, and RP-Ⅲ and RRP-Ⅱ significantly promoted the secretion of IL-1β and TNF-α by macrophages (P<0.05). The results indicated that both Rose rugosa and Rose rugosa residue were rich in functional polysaccharides, which could be applied to foods, pharmaceuticals, and cosmetics industry. Simultaneously, it would provide a theoretical basis for the further development and utilization of Rose rugosa resources.