Preparation, characterization and cytotoxicity assessment of a novel selenized polysaccharide from Morchella sextelata

Selenylation modification has been widely developed to improve the biological effects of natural polysaccharides. In this study, a purified new polysaccharide (MSP-4) was isolated from Morchella Sextelata, and selenized into SeMSP-4 using the HNO3-Na2SeO3 method. The selenium (Se) content of SeMSP-4 was 101.81 ± 9.90 mg/kg, and the molecular weight of SeMSP-4 was 1.23 × 105 Da. The FT-IR, XRD and AFM results showed that MSP-4 was successfully combined with the Se element. The structure characters of SeMSP-4 were analyzed by methylation analysis combined with 1D and 2D NMR spectroscopy. And, the radical scavenging test revealed that SeMSP-4 exhibited higher antioxidant capacities in vitro than MSP-4. The cytotoxicity analysis indicated that SeMSP-4 could dose-dependently inhibit the proliferation of HepG2 and HeLa cells, but did not show a cytotoxic effect on normal cells (HEK293). Furthermore, SeMSP-4 stimulation significantly increased the macrophage viability and enhanced NO production in macrophage cells. This study suggested that SeMSP-4 could be utilized as a potential selenium source with antioxidant, antitumor, and immunostimulatory activities.