Comparison of structural characteristics and anti-tumor activity of two alkali extracted peach gum arabinogalactan.

Two polysaccharides, PGP-90 and PGP-100 (molecular weights of 7.59 × 102 kDa and 10.48 × 102 kDa, respectively), were isolated from Peach gum using alkaline electrolyte water as an extraction solution. Structural characterization showed that PGP-90 and PGP-100 are AG-II arabinogalactans with ß-D-(1 â†’ 6)-Galp as the main chain and 1 â†’ 3 Araf and 1 â†’ 5 Araf branched chains at O-3 and O-4 positions. Animal experiments showed that PGP-90 and PGP-100 significantly improved immune function, enhance the proliferative capacity of lymphocytes and phagocytosis of peritoneal macrophages, and regulated the ratio of lymphocyte subpopulations in S180 tumor-bearing mice. Meanwhile, PGP-90 and PGP-100 promoted the secretion of cytokines (TNF-α, IFN-γ, and IL-2) by activated macrophages and blocked apoptosis at the G1 phase, resulting in tumor suppression rates of 40.80 % and 46.30 % (100 mg/kg), respectively, with PGP-100 demonstrating stronger in vivo anti-tumor activity. The above experimental results indicate that Peach gum polysaccharides have the potential to be functional anti-tumor agents.

Structural characteristics and anti-tumor activity of alcohol-precipitated polysaccharides from Cordyceps militaris under different ethanol concentrations.

Six Cordyceps militaris polysaccharides (named CMP-1, CMP-2, CMP-3, CMP-4, CMP-9, and CMP-A) were obtained by fractional alcohol precipitation. The experimental results showed that the six Cordyceps militaris polysaccharides had similar chemical composition and spectral features, and different molecular weights, monosaccharide compositions and anti-tumor activities. Purification of CMP-9 yielded the small molecule polysaccharide LMW-CMP (3.06 kDa). Structural experiments showed that LMW-CMP is an α-glucan with (1 â†’ 4)-α-D-Glcp as the main chain and a glucose branched chain attached at the O-6 position. The results of cell experiments showed that LMW-CMP could effectively inhibit the growth and proliferation of HepG2 cells, activate the downstream NF-κB signaling pathway through the MAPK pathway to induce apoptosis of HepG2 cells, and block apoptosis at the G1 phase. Animal experiments showed that LMW-CMP inhibited the proliferation of tumor cells in H22 tumor-bearing mice by improving the state of immune organs, increasing the activity of immune cells and cytokine levels in the body, and regulating the distribution of lymphocyte subpopulations, with a tumor inhibition rate of 45.70 % (200 mg/kg).

Selenochemical modification of low molecular weight polysaccharides from Grifola frondosa and the mechanism of their inhibitory effects on gastric cancer cells.

An important micronutrient involved in immune response and antitumor is selenium. LMW-GFP, a polysaccharide extracted from Grifola frondosa seed bodies, has a relatively weak antitumor effect on BGC-823 and MFC cells in vitro, whereas selenium binding to LMW-GFP can significantly increase the in vitro antitumor activity of LMW-GFP. In this study, Se-LMW-GFP was prepared by the HNO3-Na2SeO3 method, and the structures of LMW-GFP and Se-LMW-GFP were characterized by UV-visible spectroscopy of absorption, FTIR spectroscopy, and electron scanning microscopy, and these structural analyses showed that selenium was successfully complexed to LMW-GFP. The selenium content of Se-LMW-GFP was measured to be 2.08 % ± 0.08 % by ICP-MS. The anti-tumor activity of LMW-GFP before and after selenium modification was compared by cellular experiments, and the findings indicated that the anti-tumor activity of Se-LMW-GFP was considerably improved over that of LMW-GFP, and inhibited the proliferation of BGC-823 cells and MFC cells through a combination of the Fas/FasL-mediated exogenous death receptor pathway as well as the endogenous mitochondrial pathway. Our results suggest that Se-LMW-GFP not only has great potential for natural health food and anti-gastric cancer drug development but is also a good selenium supplement.

Structural characteristics of a low molecular weight velvet antler protein and the anti-tumor activity on S180 tumor-bearing mice.

Velvet antler is a traditional Chinese medicine with various pharmacological values, which is an important raw material for traditional Chinese medicinal wine. Nevertheless, the chemical compositions and bioactivities of velvet antler residue used for making medicinal wine are rarely reported, leading to a waste of resources. In this study, a velvet antler protein (VA-pro) was extracted from velvet antler residue by simulating the gastrointestinal digestion, and its composition, structural characteristics and in vivo anti-tumor activities were determined and investigated. VA-pro possessed high purity with a relatively low molecular weight as 22.589 kDa under HPLC, one- and two-dimensional electrophoresis, and it contained high contents of Pro, Gly, Glu and Ala. Besides, the secondary structure of VA-pro was dominated by ß-turn and ß-sheet, and VA-pro possessed similar protein sequence, isoelectric point and amino acid compositions to hypothetical protein G4228_020061. The in vivo results substantiated that VA-pro could improve the body weights and immune organ indices, increase the expressions of sera cytokines and regulate the distributions of T and B lymphocytes subsets in peripheral blood of S180 tumor-bearing mice. Furthermore, VA-pro could effectively inhibit solid S180 tumors growth by inducing S phase cell cycle arrest mediated through mitochondria. To summarize, our study provided theoretical support that VA-pro had the potential to be used as an immunopotentiator in immunocompromised or cancer-bearing hosts.

Preparation, Antioxidant and Immunoregulatory Activities of a Macromolecular Glycoprotein from Salvia miltiorrhiza.

Salvia miltiorrhiza has exhibited various bioactive functions due to the existence of polysaccharides, hydrophilic phenolic acids, diterpenoid quinones, and essential oils. However, little research has reported the glycoprotein preparation and corresponding bioactivities. In this study, the water-soluble glycoprotein from S. miltiorrhiza roots was firstly isolated with the extraction process optimized by response surface methodology, and then, the preliminary structural properties, and the antioxidant and immunoregulatory activities were investigated. Results showed that the extraction conditions for higher extraction yields were identified as follows: ultrasonic power of 220 W, ultrasonic time of 2.0 h, extraction temperature of 60 °C, liquid/solid ratio of 20 mL/g, and the glycoprotein yields of 1.63 ± 0.04%. Structural analysis showed that the glycoprotein comprised protein and polysaccharide (contents of 76.96% and 20.62%, respectively), with an average molecular weight of 1.55 × 105 Da. Besides, bioactivities analysis showed that the glycoprotein presented strong scavenging effects on multiple free radicals, and effectively enhanced the antioxidant enzyme activities and immunological indicators in cyclophosphamide-induced immunocompromised mice dose-dependently. These data demonstrated that S. miltiorrhiza glycoprotein presented the potential to be a novel edible functional compound, and could be practically applied in the food industry.

Structural characterization of a low molecular weight Bletilla striata polysaccharide and antitumor activity on H22 tumor-bearing mice.

In this study, a novel low molecular weight polysaccharide (named LMW-BSP) was extracted from Bletilla striata at 4 °C. The results of structural characteristics analysis showed that LMW-BSP was a 23 kDa neutral polysaccharide contained glucose and mannose at a molar ratio of 1.00:1.26. Structural investigations of the periodate oxidation studies, Smith-degradation as well as methylation were performed, and combined with 1D and 2D NMR spectroscopy, the main chain residues sequence of LMW-BSP was concluded to be: α-D-Manp-(1 â†’ 3)-ß-D-Manp-(1 â†’ [4)-ß-D-Glcp-(1]2 â†’ 4)-ß-D-Manp-(1 â†’ 3)-ß-D-Manp-(1→. Moreover, the antitumor activity of LMW-BSP was evaluated in H22 tumor-bearing mice. And the results suggested that LMW-BSP could effectively improve immune cells activities and lymphocytes subsets proportions dose-dependently in tumor-bearing mice, leading to the apoptosis of H22 cells via G1 phase arrested. LMW-BSP inhibited tumor growth and exhibited antitumor effects in vivo. And it supported considering the novel polysaccharide as a potential drug component in hepatocellular carcinoma treatment.

The immunosuppressive effects of low molecular weight chitosan on thymopentin-activated mice bearing H22 solid tumors.

In the present study, the low molecular weight of chitosan (CS) was prepared and its activity on thymopentin-activated mice bearing H22 solid tumors was further researched. The purity and molecular weight of CS were determined by UV and HPGPC spectra, and its immunosuppressive effects on H22 tumor-bearing mice were evaluated through determination on immune organs, cells and cytokines. Results showed that CS contained little impurities with the average molecular weight of 1.20 × 104 Da. The in vivo antitumor experiments demonstrated that CS facilitated to destroy immune organs (thymuses and spleens), suppress immune cells (lymphocytes, macrophages and NK cells) activities and reduce immune-related cytokines (TNF-α, IFN-γ, IL-2 and IL-4) expressions of H22 tumor-bearing mice even with simultaneous TP5 stimulation. Our data suggested that CS could not be applied to improve immune response in cancer-bearing patients, but might be employed for treatments on autoimmune diseases or organ transplant patients.