Boletus aereus polysaccharide-stabilized selenium nanoparticles: Structural characterization and in vitro antioxidant, anti-inflammatory, and antiproliferative activities.

Boletus aereus polysaccharides (BLPs) are important bioactive macromolecules with potential antioxidant, anti-inflammatory, and antiproliferative activities. In this study, BLPs were isolated and structurally characterized, and then used as natural stabilizing macromolecules for the preparation of selenium nanoparticles (BLPs-SeNPs). The purified BLPs (Mw = 16.689 kDa) were identified as highly branched heteropolysaccharides mainly composed of glucose, galactose, mannose, and fucose. BLPs-SeNPs displayed a uniform hydrodynamic size (~182 nm), a negative zeta potential (-11.79 mV), and good colloidal stability in different media. Compared with BLPs alone, BLPs-SeNPs exhibited enhanced radical-scavenging, antioxidant, anti-inflammatory, and antiproliferative activities in vitro. In hydrogen peroxide (H2O2)-challenged HepG2 cells, BLPs-SeNPs alleviated oxidative damage and regulated the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) pathway. In lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, they reduced nitric oxide (NO) production and the release of pro-inflammatory cytokines. In addition, BLPs-SeNPs showed stronger inhibitory and pro-apoptotic effects on tumor cells than BLPs alone. Overall, these results indicate that BLPs can serve as effective natural stabilizers for selenium nanoparticles and that the resulting BLPs-SeNPs possess promising in vitro bioactivities.