Effects of selenylation modification on the antioxidative and immunoregulatory activities of polysaccharides from the pulp of Rose laevigata Michx fruit

Selenylation modification has been widely utilized to improve the activity of polysaccharides and to develop novel sources of selenium (Se) supplements. A purified pulp polysaccharide of Rose laevigata Michx fruit (PPRLMF-2) was selenized into Se-PPRLMF-2 in this study. PPRLMF-2 + Se was formulated by Na2SeO3 according to the Se content of Se-PPRLMF-2. To investigate the effects of selenylation modification on the structure and functions of PPRLMF-2, the characteristics, antioxidative and immunoregulatory activities of PPRLMF-2 before and after selenylation were compared. The results showed that compared with PPRLMF-2, Se-PPRLMF-2 became an irregular fibrous network, and its Mw decreased and C-6 substitution predominated in 13C NMR spectra. Se-PPRLMF-2 significantly increased chemical antioxidant activity and reduced the oxidative damage of erythrocytes, which was not due to Se alone. Se-PPRLMF-2 significantly increased immunomodulatory activity on macrophages, which was related to Se alone. Se-PPRLMF-2 could be a good potential source of antioxidants, immune enhancers and dietary Se supplements.