Preliminary Structural Characterization of Selenium Nanoparticle Composites Modified by Astragalus Polysaccharide and the Cytotoxicity Mechanism on Liver Cancer Cells.

Astragalus alcohol soluble polysaccharide (AASP) could present superior water solubility and antitumor activity with high concentration. Selenium nanoparticles (SeNPs) have received growing attention in various fields, but their unstable property increases the application difficulties. In the present study, functionalized nano-composites (AASP-SeNPs) were synthesized through SeNPs using AASP (average molecular weight of 2.1 × 103 Da) as a surface modifier, and the preliminary structural characteristics and inhibitory mechanism on liver cancer (HepG2) cells were investigated. Results showed that AASP-SeNPs prepared under a sodium selenite/AASP mass ratio of 1/20 (w/w) were uniformly spherical with a mean grain size of 49.80 nm and exhibited superior dispersivity and stability in water solution. Moreover, the composites could dose-dependently inhibit HepG2 cell proliferation and induce apoptosis through effectively regulating mitochondria-relevant indicators including ΔΨm depletion stimulation, intracellular ROS accumulation, Bax/Bcl-2 ratio improvement, and Cytochrome c liberation promotion. These results provide scientific references for future applications in functional food and drug industries.

Synthesis of macromolecular Astragalus polysaccharide-nano selenium complex and the inhibitory effects on HepG2 cells.

In the present study, the previously obtained macromolecuar-weight Astragalus polysaccharide (average molecular weight of 1.61 × 106 Da) was used as a stabilizer and dispersing agent for nano-composites preparation by modifying selenium nanoparticles, and then the anti-hepatoma activity on HepG2 cells was investigated as well. Results showed that the nano-composites were obtained under polysaccharide concentration of 2 mg/mL and selenium/polysaccharide mass ratio of 1:15, and exhibited symmetrical spheroid with an average diameter of 62.3 nm, which has a good stability for 35 days at 4 °C. Furthermore, the in vitro anti-hepatoma experiments demonstrated that the composites could significantly inhibit the proliferation of HepG2 cells in a dose-dependent manner, and could induce the morphological changes, arrest the cell cycle in S phase, finally triggering HepG2 cells apoptosis through mitochondrial pathway. These data revealed that the composites had the potential to be a novel therapeutic drug or adjuvant for hepatoma-bearing patient treatments.

Ultrasonic-Assisted Extraction of Codonopsis pilosula Glucofructan: Optimization, Structure, and Immunoregulatory Activity.

In recent years, multiple edible polysaccharides from Codonopsis pilosula were mainly isolated with high average molecular weights and exhibited various bioactivities, but it was proven that low-molecular-weight polysaccharides could exert stronger activities due to the superior water solubility and permeability. In the present study, the water-soluble polysaccharide C. pilosula with low molecular weight was isolated under ultrasonic assistance at 30 °C, the extraction process was optimized via response surface method (RSM), and the structure and immunoregulatory activity were further investigated. The maximum yield (4.86%) for crude polysaccharides (cCPPs) was obtained under following parameters: ultrasonic power of 370 W, liquid/material ratio of 33 mL/g, ultrasonic time of 81 min. Subsequently, the cCPPs were further purified through dialysis and Sephadex G-25 column to acquire purified polysaccharide (CPPs). Structural analysis indicated that CPPs was a glucofructan (average molecular weight of 4.23 × 103 Da) with (2→1)-ß-D-Fruf and (1→)-α-D-Glcp as the backbone branched by (2→6)-ß-D-Fruf. Additionally, CPPs could enhance immunoregulatory function by stimulating NO production and cytokine (IL-6 and TNF-α) secretion of RAW264.7 macrophages dose-dependently, which presented no cytotoxic effects. These data suggest that CPPs have the potential to be used as a nutritional dietary compound and natural immunostimulant supplement in the food industry.

Antitumor and immunoregulatory activities of a novel polysaccharide from Astragalus membranaceus on S180 tumor-bearing mice.

The Astragalus membranaceus polysaccharide (APS4) with direct cytotoxicity on various cancer cells has been prepared in our previous study, while the underlying therapeutic role of APS4 on solid tumors in vivo hasn't been investigated yet. Therefore, in this paper, the lymphocytes-mediated antitumor and immunoregulatory activities of APS4 were researched by establishing S180 tumor-bearing mice model. Flow cytometry analysis revealed that APS4 could effectively regulate the percentages of CD3+, CD4+, CD8+ T cells and CD19+ B cells in thymus, peripheral blood and spleen of S180 tumor-bearing mice, dose-dependently. H&E staining and cell cycle determination of solid tumors manifested that APS4 treatment could significantly inhibit the growth of solid tumors by inducing cells apoptosis. Furthermore, two-dimensional electrophoresis and western blot analysis further demonstrated that APS4 could activate antitumor-related immune cells and promote anaerobic metabolism of tumor microenvironment, thereby causing the apoptosis of S180 tumor cells. These data implicated that APS4 could be used as a potential dietary supplement for immune enhancement.