Tea Polysaccharides Inhibit Colitis-Associated Colorectal Cancer via Interleukin-6/STAT3 Pathway.

The interleukin-6 (IL-6)/signal transducer and activator of transcription (STAT)-3 signaling pathway regulates proliferation and survival of intestinal epithelial cells and has profound impact on the tumorigenesis of colitis-associated cancer (CAC). Tea polysaccharides (TPS) are the major nutraceutical component isolated from tea-leaves and are known to possess antioxidant, anti-inflammatory, and antitumor bioactivities. Here, we investigated the antitumor activities of TPS on CAC using the azoxymethane/dextran sulfate sodium (AOM/DSS) mouse model and IL-6-induced colorectal cancer cell line (CT26) and determined whether TPS exerted its antitumor effects through the IL-6/STAT3 pathway. Results demonstrated that TPS significantly decreased the tumor incidence, tumor size, and markedly inhibited the infiltration of pro-inflammatory cells and the secretion of pro-inflammatory cytokines via balancing cellular microenvironment. Furthermore, we found that TPS suppressed the activation of STAT3 and transcriptionally regulated the expressions of downstream genes including MMP2, cyclin Dl, survivin, and VEGF both in vivo and in vitro. Thus, it was concluded that TPS attenuated the progress of CAC via suppressing IL-6/STAT3 pathway and downstream genes' expressions, which indicated that TPS may be a hopeful antitumor agent for the prevention and treatment of colon cancer.

Tea Polysaccharide Prevents Colitis-Associated Carcinogenesis in Mice by Inhibiting the Proliferation and Invasion of Tumor Cells.

The imbalance between cell proliferation and apoptosis can lead to tumor progression, causing oncogenic transformation, abnormal cell proliferation and cell apoptosis suppression. Tea polysaccharide (TPS) is the major bioactive component in green tea, it has showed antioxidant, antitumor and anti-inflammatory bioactivities. In this study, the chemoprophylaxis effects of TPS on colitis-associated colon carcinogenesis, especially the cell apoptosis activation and inhibition effects on cell proliferation and invasion were analyzed. The azoxymethane/dextran sulfate sodium (AOM/DSS) was used to induce the colorectal carcinogenesis in mice. Results showed that the tumor incidence was reduced in TPS-treated AOM/DSS mice compared to AOM/DSS mice. TUNEL staining and Ki-67 immunohistochemistry staining showed that the TPS treatment increased significantly the cell apoptosis and decreased cell proliferation among AOM/DSS mice. Furthermore, TPS reduced the expression levels of the cell cycle protein cyclin D1, matrix metalloproteinase (MMP)-2, and MMP-9. In addition, in vitro studies showed that TPS, suppressed the proliferation and invasion of the mouse colon cancer cells. Overall, our findings demonstrated that TPS could be a potential agent in the treatment and/or prevention of colon tumor, which promoted the apoptosis and suppressed the proliferation and invasion of the mouse colon cancer cells via arresting cell cycle progression.

Carboxymethylation of polysaccharide from Cyclocarya paliurus and their characterization and antioxidant properties evaluation.

In this study, three chemically carboxymethyl polysaccharides (CM-CPs) were derived from Cyclocarya paliurus polysaccharides. The physicochemical properties and antioxidant activity in vitro of carboxymethyl derivatives were determined. The results of degree of substitution and FT-IR analysis showed the carboxymethylation of polysaccharides were successful. Compared with unmodified polysaccharides, the contents of carbohydrate and protein were decreased while CM-CP3 with highest DS value had more uronic acid. The carboxymethyl derivatives was mainly composed of Ara, Gal, Glc, Man, GalA, with a molecular weight (Mw) of 1.03-1.08 × 10(6)Da. Compared with the native polysaccharide, the CM-CP3 with highest DS and Mw exhibited the highest antioxidant activity in ß-carotene-linoleic acid assay. However, the superoxide radical and hydroxyl radical scavenging activity were decreased by CM-CPs. These results demonstrated appropriate carboxymethylation modification could enhance the potential of C. paliurus polysaccharide as oxidation inhibitor.

Preparation, characterization and antioxidant activities of acetylated polysaccharides from Cyclocarya paliurus leaves.

In this study, polysaccharides extracted from Cyclocarya paliurus leaves were modified to obtain its three acetylated derivatives, Ac-CP1, Ac-CP2, and Ac-CP3. The physicochemical characteristics and antioxidant activities of acetylated derivatives were investigated. The results of chemical and FT-IR spectrum analysis showed differences between acetylated derivatives and native C. paliurus polysaccharide, which revealed that the acetylation were successful. Relative to unmodified polysaccharide, the protein contents of acetylated derivatives decreased, while carbohydrate values increased. The molecular weight (Mw) of acetylated derivatives were approximately 1.05-1.09×10(6)Da and were mainly composed of Ara, Gal, Glc, Man, GalA. Ac-CP1 with relatively low degree of substitution (0.13±0.01) exhibited excellent antioxidant activity in DPPH radical assay (95.21±0.89%), and also had strong chelating activity on ß-carotene-linoleic acid assay (34.64±2.07%) at 0.5mg/ml. In addition, scanning electron microscope (SEM) observations suggested that acetylation could change the morphology and structure of polysaccharides from C. paliurus leaves.

Sulfated polysaccharides from Cyclocarya paliurus reduce H2O2-induced oxidative stress in RAW264.7 cells.

In this study, two sulfated polysaccharides (S-CP1-4 and S-CP1-8) from Cyclocarya paliurus were produced by chlorosulfonic acid-pyridine method. Hydrogen peroxide (H2O2) was used to develop an oxidative stress model in the mouse macrophage cell line RAW264.7. Effects of the two sulfated polysaccharides on H2O2-induced oxidative stress were investigated. The results showed that S-CP(1-8) improved the viability of the H2O2-induced stressed RAW264.7 cells, as well as inhibited the lipid oxidation as determined by the level of malondialdehyde (MDA). Meanwhile, treatment with S-CP(1-4) increased superoxide dismutase (SOD) activity in these cells. The sulfated polysaccharides were found to have a better protective effect against H2O2-induced oxidative stress as compared to the native polysaccharide. Scanning electron microscopy also showed a significant change in the surface morphology of sulfated polysaccharides, but the degradation of main chain of polysaccharides was unconspicuous according to the results of monosaccharide composition. In addition, the sulfated polysaccharides had noticeable DPPH radical scavenging activity. In summary, our results demonstrated that H2O2 was able to induce oxidative stress in RAW264.7 cells, and sulfated group might play an important role in resistance to H2O2-induced oxidative damage.

Extraction, chemical composition and antioxidant activity of flavonoids from Cyclocarya paliurus (Batal.) Iljinskaja leaves.

Microwave-assisted extraction of flavonoids from Cyclocarya paliurus (Batal.) Iljinskaja leaves, its chemical composition and antioxidant activity were investigated in this study. The influences of parameters including temperature, extraction time, ratio of material to solvent and solvents on the yield of flavonoids were studied. The optimal conditions were determined and the quadratic response surfaces were drawn from the mathematical models. The maximum extraction yield of 15.64 mg/g was achieved at temperature of 76.8 °C, extraction time of 15 min, alcohol concentration of 63.2% and ratio of solvent to material of 21.4:1. Five main constituents in the extract including quercetin-3-O-ß-D-glucuronide, quercetin, kaempferol-3-O-ß-D-glucuronide, kaempferol-7-O-α-L-rhamnoside and kaempferol were identified by LC-MS. In vitro antioxidant assays showed that the extract exhibited a strong DPPH radical-scavenging ability with IC50 value of 0.146 mg/mL. Results indicated that MAE was a suitable approach for the selective extraction of flavonoids from C. paliurus (Batal.) Iljinskaja leaves.

Separation of water-soluble polysaccharides from Cyclocarya paliurus by ultrafiltration process.

In this study, ultrafiltration membrane process was employed to separate polysaccharides from Cyclocarya paliurus (Batal.) Iljinskaja (C. paliurus) to simulate industrial production. Meanwhile, the molecular weight distribution of C. paliurus polysaccharides was investigated by gel permeation chromatography. Four fractions were obtained and named as CPPS-A, CPPS-B, CPPS-C and CPPS-D, respectively. CPPS-A and CPPS-B contained approximately 69.5% and 12.7% of polysaccharides, whose molecular weight were in the range of 100-300 kDa and 120 kDa, respectively. CPPS-C was comprised of two polysaccharides with average molecular weight of 40 kDa and 15 kDa. Results showed that ultrafiltration resulted in the removal of parts of small molecule weight polysaccharides, the increase of proportion of high molecule weight ones and the obvious improvement of quality of products. Compared with ethanol precipitation and gel permeation chromatography techniques, ultrafiltration showed many advantages, and also provided theoretical support for industrial manufacturing of C. paliurus polysaccharides in separation.

Analysis of monosaccharide composition of Cyclocarya paliurus polysaccharide with anion exchange chromatography.

A simple, rapid and sensitive analytical method for the determination of monosaccharide composition in Cyclocarya paliurus polysaccharide was developed and validated. This method was based on hydrolysis of the polysaccharides followed by high-performance anion-exchange chromatography analysis. The effects of sodium hydroxide concentration and column temperature on retention and separation of the monosaccharide were investigated with Carbo PAC™ PA10 analytical column. The established method was validated and the results showed that this method had good linearity (R(2), 0.9987-0.9999), adequate accuracy (98.53-102.13% recovery), high precision (relative standard deviation <3.8%) and sensitive detection limits (2.57-7.86 nM), with a simple preparation of the samples (no need to derivatize the samples) and short run time (20 min). The results showed that the C. paliurus polysaccharide consisted of rhamnose, arabinose, galactose, glucose, mannose and xylose in the molar ratio of 1.00:1.85:3.26:3.12:0.85:0.29.

Simultaneous analysis of 18 mineral elements in Cyclocarya paliurus polysaccharide by ICP-AES.

The contents of 18 kinds of mineral elements in Cyclocarya paliurus polysaccharide samples were determined by ICP-AES. The limits of detection (LOD) of the method for 18 elements were in the range of 0.01-3.80 mg/kg. The average recoveries obtained by the standard addition method were found between 94.34% and 105.69% (RSD, 1.01-4.23%). The results showed that C. paliurus polysaccharides were abundant in major and trace elements which are healthy for human body. The contents of Ca, Al, Mg, K, Fe, Mn and P were very high, ranging from 274.5±10.3 to 5980.0±102.7 mg/kg, while the contents of Zn, Na, Se, Cr, Pb, Cu and As ranged from 0.9±0.1 to 37.1±4.2 mg/kg. Finally, the levels of Ni, Cd, V and Co were not detected in the samples. ICP-AES is a simple, precise and efficient method for the determination of many mineral elements in polysaccharide samples simultaneously.

Purification, physicochemical characterisation and anticancer activity of a polysaccharide from Cyclocarya paliurus leaves.

A Cyclocarya paliurus (Batal.) Iljinskaja polysaccharide (CPP) was isolated and purified by hot water extraction, ethanol precipitation, deproteinisation and anion-exchange chromatography. Its physicochemical properties were characterised by gel permeation chromatography (GPC), gas chromatography-mass spectrometry (GC-MS), thermal gravimetric analysis (TGA), Fourier transform infrared spectrometry (FTIR), UV-visible spectrophotometry, dynamic light scattering (DLS) and viscometry analysis. The anticancer effect of CPP in human gastric cancer HeLa cells was also evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results showed that the molecular weight of CPP was 900 kDa, and it contained 64.8% total sugar, 23.5% uronic acid, 9.26% protein, and six kinds of monosaccharides, including glucose, rhamnose, arabinose, xylose, mannose and galactose, with molar percentages of 32.7%, 9.33%, 30.6%, 3.48%, 10.4%, and 13.5%, respectively. Furthermore, the results showed that CPP exhibited a strong inhibition effect on the growth of human gastric cancer HeLa cells.

Ultrasonic-assisted extraction, antimicrobial and antioxidant activities of Cyclocarya paliurus (Batal.) Iljinskaja polysaccharides.

Recently, renewed interest has grown in the use of ultrasonic-assisted extraction as an alternative approach to the traditional extraction methods. In this study, this novel extraction method was used to isolate polysaccharides from Cyclocarya paliurus (Batal.) Iljinskaja, and response surface methodology (RSM) was employed to optimize the extraction conditions. The optimal conditions for the extraction of polysaccharides were determined to be the ratio of liquid to solid of 8, extraction time of 59 min and extraction temperature of 58 °C. Under these optimal conditions, the yield of polysaccharides obtained was 4.91 ± 0.11%, which was well matched with the value predicted by the model. In vitro antioxidant assays showed that the polysaccharides exhibited strong DPPH radicals (92.09% at 0.25 mg/ml) and self-oxidation of 1,2,3-phentriol (37.22% at 1 mg/ml) scavenging activities, moderate hydroxyl radicals (43.18% at 1 mg/ml) scavenging activity and lipid peroxidation inhibitory effect (31.66% at 1 mg/ml). In addition, the polysaccharides showed moderate antimicrobial activity.

Optimisation of microwave-assisted extraction of polysaccharides from Cyclocarya paliurus (Batal.) Iljinskaja using response surface methodology.

BACKGROUND: Cyclocarya paliurus (Batal.) Iljinskaja is a well-known edible and medicinal plant in China and is commonly called the 'sweet tea tree'. It has been reported to have a broad range of therapeutic and nutritional values in lowering blood sugar, blood lipids and blood pressure. However, much of the annual C. paliurus production is wasted. Recent reports have suggested that polysaccharides are the main active ingredients responsible for the observed bioactivities of C. paliurus. In this study, response surface methodology was used to determine the optimal conditions for microwave-assisted extraction (MAE) of polysaccharides from C. paliurus. RESULTS: The optimal conditions for MAE of polysaccharides were a duration of microwave radiation of 20.8 min, a temperature of 100.9 degrees C and a water/material ratio of 22.1:1. Under these conditions the yield of polysaccharides was up to 5.04 +/- 0.09%. Compared with conventional heat reflux extraction and ultrasound-assisted extraction, MAE of polysaccharides from C. paliurus (Batal.) Iljinskaja saved a lot of time and gave the highest yield. CONCLUSION: The present study suggests that MAE is a good alternative method for the extraction of polysaccharides from C. paliurus (Batal.) Iljinskaja.

Simultaneous determination of organophosphorus pesticides in Chinese herbal medicines by microwave-assisted extraction coupled with dispersive-solid phase extraction and gas chromatography.

A reliable, rapid and nontoxic analytical method was proposed for the simultaneous determination of 16 organophosphorus pesticides in Chinese herbal medicines. The pesticides were extracted by ethanol and the experimental variables, such as temperature, extraction time and volume of ethanol, were optimized through orthogonal array experimental design. Cleanup of extracts was performed with dispersive-solid phase extraction using primary secondary amine as the sorbent. The determination of pesticides in the final extracts was carried out by gas chromatography-flame photometric detection. Under optimized conditions the obtained recoveries, except for isocarbophos, were in the range 73.8-123%, with relative standard deviations equal to or lower than 15.2% and limits of detection ranging from 0.001 to 0.009 mg/kg.