The inhibitory effects of selenium nanoparticles modified by fructose-enriched polysaccharide from Codonopsis pilosula on HepG2 cells

Ethanol volume fraction of 80% was widely applied for polysaccharides precipitation from Codonopsis pilosula water-leach liquor, while few researches focused on the dissolved components in 80% alcohol solution. Selenium nanoparticles presented strong biological activities with low toxicity, but the poor stability limited the practical applications. This study isolated a C. pilosula polysaccharide from the supernate after 80% ethanol precipitation, which was used as surface decorator for nano-composites preparation, and then the structural performance, storage stability and inhibitory mechanism on HepG2 cells were investigated. Results showed that the C. pilosula polysaccharide was mainly composed of fructose and glucose (molar ratio of 2.68:1.00) with average molecular weight of 3.21 × 103 Da. Additionally, the nano-composites were successfully prepared under Na2SeO3 to polysaccharide (2.0 mg/mL) ratio (w:w) of 1:20, and exhibited homogeneous distribution with an average particle size of ~ 75 nm and superior stability at 4 °C for at least 35 days. Besides, the nano-composites effectively inhibited HepG2 cells proliferation dose-dependently, and induced the mitochondrial dysfunction via improving Bax expressions and descending Bcl-2 expressions, resulting in the release of mitochondrial cytochrome c to cytoplasm and the activation of caspase-9 / − 3, thereby promoting cells apoptosis. These results would effectively improve utilization rate of C. pilosula and provide theoretical foundation for clinical applications of the composite in hepatoma-bearing patients.