Daoyuan Ren

Purification, characterization and antioxidant activities of polysaccharides from thinned-young apple

Purification, characterization and antioxidant activities of polysaccharides from thinned-young apple (TYA) were investigated in the study. A water-soluble polysaccharide (TYAP) was obtained with hot water extraction, which was further purified by chromatography of Cellulose DEAE-52 and Sephadex G-150 to get three purified fractions of TYAP-1, TYAP-2 and TYAP-3. HPLC analysis showed that the three fractions were mainly composed of galactose and arabinose with the average molecular weights of 115 kDa, 479 kDa and 403 kDa, respectively and the monosaccharide compositions of TYAP-2 and TYAP-3 were more complicated than that of TYAP-1. Moreover, TYAP fractions of three had no absorptions at 260 nm and 280 nm in the UV spectrum, indicating the absence of protein and nucleic acid. Their structure properties were further confirmed by FT-IR. In vitro antioxidant activities of three fractions were characterized by DPPH(•), HO(•), O2(•-) and ferric-reducing antioxidant power systems. The results indicated that TYAP-1, TYAP-2 and TYAP-3 possessed significant antioxidant effects in a concentration-dependant manner in the tested concentration range of 0.25-5.0mg/mL. Among the fractions tested, TYAP-3 showed significantly higher antioxidant activity than that of TYAP-1 and TYAP-2. All of these findings provide a scientific basis for the further use of polysaccharides from thinned-young apple.

Hypoglycemic and hepatoprotective effects of polysaccharides from Artemisia sphaerocephala Krasch seeds.

Intake of dietary high fructose (HF) exerts a number of adverse metabolic effects. The present study was to investigate whether Artemisia sphaerocephala Krasch seed polysaccharides (ASKP) alleviated hyperglycemia, hepatic steatosis and oxidative injury in mice fed HF water. After 8 weeks of the experiment, administration of ASKP at 400 and 800mg/kgbw significantly reduced the fasting serum glucose, insulin concentrations and the homeostasis model assessment of basal insulin resistance (HOMA-IR) of the mice fed 20% HF water. In the oral glucose tolerance test, the administration of ASKP at 400 and 800mg/kgbw had a reduced plasma glucose concentrations after 15min of glucose loading in HF-fed mice, indicating that ASKP improved glucose intolerance. ASKP also remarkably ameliorated the HF-induced elevation of liver lipid contents and oxidative injury in mice, and caused the reduction of liver lipid peroxidation and the elevation of hepatic antioxidant system. Histopathology of the liver by conventional H&E and Oil Red O staining confirmed the liver steatosis and oxidative injury induced by HF diet and the hepatoprotective effect of ASKP. This is the first report showing that ASKP can ameliorate the high fructose-induced hyperglycemia, hepatic steatosis and oxidative injury.

Optimization for ultrasound-assisted extraction of polysaccharides with chemical composition and antioxidant activity from the Artemisia sphaerocephala Krasch seeds.

Artemisia sphaerocephala Krasch seeds polysaccharides have been reported to have a variety of important biological activities. However, effective extraction of Artemisia sphaerocephala Krasch seeds polysaccharides is still an unsolved issue. In this study, the orthogonal rotatable central composite design was employed to optimize ultrasound-assisted extraction conditions of Artemisia sphaerocephala Krasch seeds polysaccharides. Based on a single-factor analysis method, ultrasonic power, extraction time, solid-liquid ratio and extraction temperature were shown to significantly affect the yield of polysaccharides extracted from the A. sphaerocephala Krasch seeds. The optimal conditions for extraction of Artemisia sphaerocephala Krasch seeds polysaccharides were determined as following: ultrasonic power 243W, extraction time 125min, solid-liquid ratio 64:1 and extraction temperature 64°C, where the experimental yield was 14.78%, which was well matched with the predicted value of 14.81%. Furthermore, ASKP was identified as a typical heteropolysaccharide with d-galacturonic acid (38.8%) d-galactose (20.2%) and d-xylose (15.5%) being the main constitutive monosaccharides. Moreover, Artemisia sphaerocephala Krasch seeds polysaccharides exhibited high total reducing power and considerable scavenging activities on DPPH, hydroxyl and superoxide radicals, in a concentration-dependent manner in vitro.

Chemical characterization of Pleurotus eryngii polysaccharide and its tumor-inhibitory effects against human hepatoblastoma HepG-2 cells.

This study was designed to investigate the chemical characterization and antitumor effects of Pleurotus eryngii polysaccharides (PEP). The crude PEP was fractionated into two fractions, namely PEP-1 and PEP-2. HPLC analysis showed that PEP-1 and PEP-2 were heteropolysaccharides mainly composed of glucose with the average molecular weights of 2.54×10(4)Da (PEP-1) and 4.63×10(5)Da (PEP-2), respectively. High molecular mass PEP-2 was shown to exhibit stronger growth inhibition against human hepatoblastoma HepG-2 cells in comparison with PEP-1. Flow cytometric analysis showed that PEP-2 exerted a stimulatory effect on apoptosis of HepG-2 cells, and induced the cell-cycle arrest at the S-phase, with the observation of intracellular ROS production. These findings suggest that the polysaccharides, especially PEP-2, are very important nutritional ingredients responsible for the anticancer health benefits of P. eryngii.

Antioxidant and antitumor effects of polysaccharides from the fungus Pleurotus abalonus

Dietary supplement of edible Pleurotus abalonus (P. abalonus) rich in fungal polysaccharides is associated with anticancer health benefit. We here isolated the polysaccharides (PAP) from the fruiting bodies of P. abalonus, and evaluated the antiproliferative activity of the polysaccharides in human colorectal carcinoma LoVo cells. HPLC analysis showed that PAP consisted of D-mannose, D-ribose, l-rhamnose, D-glucuronic acid, D-glucose and D-galactose, and their corresponding mole percentages were 3.4%, 1.1%, 1.9%, 1.4%, 87.9% and 4.4%, respectively. PAP was shown to exert a high antioxidant activity in vitro and a dose-dependent antiproliferative effect against LoVo cancer cells. Flow cytometry analysis demonstrated that PAP exhibited a stimulatory effect on apoptosis of LoVo cells, and induced the cell-cycle arrest at the S phase. We also found that PAP could increase the generation of intracellular ROS which was a critical mediator in PAP-induced cell growth inhibition. These findings suggest that PAP may serve as a potential novel dietary agent for human colon cancer chemoprevention.

Differential effects of baicalein and its sulfated derivatives in inhibiting proliferation of human breast cancer MCF-7 cells.

This study was to investigate the anticancer effects of baicalein (Bai) and its two sulfated derivatives, namely baicalein-7-O-sulfate (BoS) and baicalein-8-sodium sulfonate (BcS). BcS was shown to exhibit stronger growth inhibition against human breast cancer MCF-7 cells, compared with structurally related Bai and BoS, where IC50 values of BoS, Bai and BcS were 97.7, 68.3 and 30.4μM, respectively. BoS, Bai and BcS were further shown to mediate the cell-cycle arrest principally in G0/G1-phase within 12h of treatment with MCF-7 cells, and after 12h, they arrested principally in S-phase. It was also found that 17.7%, 44.9% and 70.5% of MCF-7 cells entered the early phase of apoptosis when treated with 200μM BoS, Bai and BcS for 24h, followed by an intracellular ROS generation. BcS displays strong antitumor effect through ROS-dependent apoptosis pathway in MCF-7 cells, and has promising potential to be developed as an antitumor compound.

Isoorientin Prevents Hyperlipidemia and Liver Injury by Regulating Lipid Metabolism, Antioxidant Capability, and Inflammatory Cytokine Release in High-Fructose-Fed Mice

Isoorientin (ISO), a natural flavonoid, has been found to have multiple biological properties. In the present study, obese mice with high-fructose (HF)-induced liver injury were used to investigate the hepatoprotective effects of ISO. The results showed that ISO significantly reduced the serum lipid parameters in mice fed 20% HF water. Meanwhile, ISO appeared to alleviate HF-induced lipid metabolic disorders by increasing the serum levels of apo-A1 and decreasing the serum apoB levels, apoB/apo-A1 ratio, and FAS activity in the liver. ISO also remarkably ameliorated HF-induced hepatic oxidative injury and inflammation by decreasing ALT, AST, and ALP levels; enhancing antioxidant enzyme activities; and inhibiting inflammatory cytokine (TNF-α, IL-1, IL-6) release. Histopathology of liver stained by H&E and Oil Red O showed the liver steatosis and oxidative injury after HF treatment and the protective effect of ISO. Furthermore, aortic pathology observation found that ISO had a protective effect on the vascular endothelium. This is the first report that ISO efficiently inhibited HF-induced hyperlipidemia and liver injury by ameliorating lipid metabolism, enhancing the antioxidant defensedefense system, and regulating the secretion of inflammatory cytokines.

Hepatoprotective effects of phloretin against CCl4-induced liver injury in mice

ABSTRACT This study was designed to characterize the protective capacity of phloretin against acute liver oxidative injury induced by CCl4 in mice. Administration of phloretin at 100, 200 and 500 mg/kg·bw orally daily in mice for 21 consecutive days, prior to intraperitoneal injection of 0.5% CCl4/peanut oil (ip, 0.3 mL), significantly reduced the CCl4-induced inhibition of serum alanine aminotransferase, aspartate aminotransferase and lactic dehydrogenase activities. Furthermore, phloretin elevated glutathione and superoxide dismutase activities and reduced formation of malonaldehyde in the liver of mice, when compared with CCl4-intoxication mice. Moreover, phloretin also prevented the CCl4-caused liver histological alteration, as indicated by histopathological evaluation. These data collectively demonstrated the potential prospect of phloretin as functional ingredient to prevent liver injury.