Preparation, characterization and cytotoxic activity of selenium nanoparticles stabilized with a heteropolysaccharide isolated from Sanghuangporus vaninii residue.

Selenium nanoparticles (SeNPs) possess unique features with excellent bioavailability and bioactivity, but the poor stability limits its application. A combination of polysaccharides and SeNPs is an effective strategy to overcome the limitation. Herein, a heteropolysaccharide (SVL-3) with an average molecular weight of 2.428 × 10 Da was purified from the fruiting body residue of Sanghuangporus vaninii after soaking in sorghum wine, which was composed of fucose, galactose, glucose, fructose and 3-O-methyl-galactose. The main chain of SVL-3 was composed of →6)-α-3-MeO-Galp-(1→, →4)-α-D-Galp-(1→, →2,6)-β-D-Glcp-(1 → and →3)-α-D-Glcp-(1→, and the branched chain was composed of →4)-α-D-Xylp-(1 → and α-L-Fucp-(1→. For enhancing bioactivity of SVL-3 and stability of SeNPs, SVL-3-functionalized SeNPs (SVL-3-SeNPs) was prepared, which contained 45.31 % polysaccharide and 48.49 % selenium. SVL-3-SeNPs maintained an emphatic stability over 28 days at 4 °C and pH 6-8, and exhibited a higher cytotoxic effect on MCF-7 cells than SVL-3 and SeNPs. The inhibitory effect of SVL-3-SeNPs on the cancer cells may be associated with the mechanisms by inducing S-phase arrest, triggering apoptosis and elevating the protein levels of Cytochrome c, Caspases and cleaved caspases 3 and 9. These results indicated that SeNPs modified by S. vaninii polysaccharides can be utilized as a potential material for targeted antitumor drugs.