Synthesis, characterization, and cytotoxicity analysis of selenium nanoparticles stabilized by Morchella sextelata polysaccharide.

Natural bioactive molecules have been widely used as stabilizers in the functional improvement of selenium nanoparticles (SeNPs) in recent years. In this study, Morchella sextelata polysaccharide (MSP) was introduced as a novel stabilizer for the synthesis of SeNPs based on the redox system of sodium selenite and ascorbic acid. The size, morphology, stability, and anti-cancer cell activities were respectively analyzed by various methods. The results showed that the synthesized SeNPs with MSP were 72.07 ± 0.53 nm in size, red in color, spherical in shape, and amorphous in nature. MSP-SeNPs showed high scavenging activity against DPPH and ABTS radicals. And, these MSP-SeNPs exhibited a significant anti-proliferation effect on human liver (HepG2) and cervical cancer (Hela) cells in vitro, while no significant cytotoxicity against normal human kidney cells (HK-2) was observed. Moreover, the mitochondria-dependent apoptosis pathway triggered by MSP-SeNPs in HepG2 cell was identified. The expression levels of p53, Bax, cytochrome c, caspase-3 and caspase-9 were all up-regulated in HepG2 cells after MSP-SeNPs treatment, while Bcl-2 expression was down-regulated. These results suggest that MSP-SeNPs have strong potential as the food supplement for application in cancer chemoprevention.

Purification, structural characterization and immunomodulatory activities of a polysaccharide from the fruiting body of Morchella sextelata.

A novel polysaccharide (MSP-1) was isolated from the fruiting body of Morchella sextelata and purified using DEAE-52 and Sephadex G-75. The molecular weight of MSP-1 was 1.17 × 104 Da, as detected by HPLC analysis. The monosaccharide composition of MSP-1 was mannose and glucose at a ratio of 1.00: 1.25. Methylation and NMR results revealed that the backbone of MSP-1 was composed of →4)-ß-D-Manp-(1→, →4)-ß-D-Glcp-(1→, →4)-α-D-Glcp-(1→, and →4, 6)-α-D-Glcp-(1→. SEM images of MSP-1 presented a dense network structure with porous characterizations. The immunomodulatory activities of MSP-1 were evaluated using RAW264.7 cells, and the results showed that MSP-1 promoted proliferative and phagocytic activity and increased the production of NO, TNF-α and IL-6. These results indicated that MSP-1 exhibited significant immunomodulatory activities.