Qingsheng Zhao

Extraction, purification and antioxidant activities of the polysaccharides from maca (Lepidium meyenii)

Water-soluble polysaccharides were separated from maca (Lepidium meyenii) aqueous extract (MAE). The crude polysaccharides were deproteinized by Sevag method. During the preparation process of maca polysaccharides, amylase and glucoamylase effectively removed starch in maca polysaccharides. Four Lepidium meyenii polysaccharides (LMPs) were obtained by changing the concentration of ethanol in the process of polysaccharide precipitation. All of the LMPs were composed of rhamnose, arabinose, glucose and galactose. Antioxidant activity tests revealed that LMP-60 showed good capability of scavenging hydroxyl free radical and superoxide radical at 2.0mg/mL, the scavenging rate was 52.9% and 85.8%, respectively. Therefore, the results showed that maca polysaccharides had a high antioxidant activity and could be explored as the source of bioactive compounds.

Optimization of ultrasonic circulating extraction of polysaccharides from Asparagus officinalis using response surface methodology

Polysaccharides were extracted from Asparagus officinalis. A novel ultrasonic circulating extraction (UCE) technology was applied for the polysaccharide extraction. Three-factor-three-level Box-Behnken design was employed to optimize ultrasonic power, extraction time and the liquid-solid ratio to obtain a high polysaccharide yield. The optimal extraction conditions were as follows: ultrasonic power was 600 W, extraction time was 46 min, the liquid-solid ratio was 35 mL/g. Under these conditions, the experimental yield of polysaccharides was 3.134%, which was agreed closely to the predicted value. The average molecular weight of A. officinalis polysaccharide was about 6.18×10(4) Da. The polysaccharides were composed of glucose, fucose, arabinose, galactose and rhamnose in a ratio of 2.18:1.86:1.50:0.98:1.53. Compared with hot water extraction (HWE), UCE showed time-saving, higher yield and no influence on the structure of asparagus polysaccharides. The results indicated that ultrasonic circulating extraction technology could be an effective and advisable technique for the large scale production of plant polysaccharides.

Effect of drying methods on physicochemical properties and antioxidant activities of wolfberry (Lycium barbarum) polysaccharide.

In this study, an efficient drying process of Lycium barbarum L. polysaccharide (LBP) suitable for industrial production was developed and optimized. Three drying methods, including hot air drying (40-80°C), vacuum drying (40-60°C) and spray drying were test and compared. Hot air drying and vacuum drying cost long time and produced a brown product which needs further process due to the agglomeration or alveolation form. The condition of spray drying (without any excipient) was optimized by orthogonal experiment, which gave different optimum conditions based on LBP recovery rate (LBP solution concentration 1.06 g/mL, inlet air temperature 170°C, sample flow rate 15 mL/min and air speed 4.2m(3)/min) or LBP transparency (LBP solution concentration 1.04 g/mL, inlet air temperature 170°C, sample flow rate 20 mL/min and air speed 2.8m(3)/min). Pilot scale experiments showed preferable stability of LBP product quality and process parameters. Sample of spray drying (SD) had the highest scavenging free radical effects, the best appearance (LBP transparency), and uniform morphology with hollow sphere which are important properties for the reconstitution of the powder product. Considering the product appearance and product activity, the spray drying was selected to apply in industrial production.

Physicochemical characteristics of ultrasonic extracted polysaccharides from cordyceps cephalosporium mycelia.

Ultrasonic extraction (USE) of polysaccharide from cordyceps cephalosporium mycelia was introduced and compared with hot water extraction. Crude polysaccharides were investigated for morphological and thermodynamic properties. Two major fractions (USEP40-1, USEP70-1) were purified and investigated for IR spectra, molecular weights, monosaccharide compositions and antioxidant activities. The results suggested that USE gained higher extraction efficiency due to its intense extraction process. USE caused a more compact arrangement in crude polysaccharides. IR spectra of USEP40-1 and USEP70-1 were different at around 1746 cm(-1). The molecular weights of USEP40-1 and USEP70-1 were 61.4 kDa and 25.1 kDa. USEP40-1 and USEP70-1 were composed of D-mannose, D-glucose, D-galactose, L-rhamnose, and L-arabinose with molar ratio of 11.52:5.54:8.75:2.45:2.59 and 11.50:6.74:5.75:4.46:2.39, respectively. Different ABTS and hydroxyl radical scavenging activities were observed in USEP40-1 and USEP70-1.

Protective effect of polysaccharide from maca (Lepidium meyenii) on Hep-G2 cells and alcoholic liver oxidative injury in mice

To study the characterization and hepatoprotective activity of polysaccharide from maca (Lepidium meyenii), the main polysaccharide from maca (MP-1) was obtained by DEAE-52 cellulose column. The average molecular weight of MP-1 was 1067.3kDa and the polysaccharide purity was 91.63%. In order to assess the antioxidant activities of MP-1, four kinds of methods were used, including scavenging hydroxyl radical, DPPH, superoxide anion radical, and FRAP, and the results indicated high antioxidant activities. Furthermore, hepatoprotective activity of MP-1 was studied both in vitro and vivo. In vitro, the alcohol induced Hep-G2 cells model was established to evaluate the protective effect of MP-1, which demonstrated MP-1 can alleviate alcohol damage in Hep-G2 cells. In vivo, the Institute　of　Cancer　Researcch (ICR) mice were used to evaluate hepatoprotecive effects of MP-1 on alcoholic liver disease (ALD). Supplement with MP-1 supressed the triglyceride level both in serum and in hepatic tissue. In addition, MP-1 ameliorated serous transaminases increase induced by alcohol, including aspartate transaminase, alanine aminotransferase, and γ-glutamyl transpeptidase. Moreover, MP-1 also dramatically increased the superoxide dismutase, glutathione peroxidase, and glutathione s-transferase levels in alcoholic mice. Meantime, histopathologic results MP-1 lighten inflammation induced by alcohol. These results indicate that MP-1 possesses hepatoprotective activity against hepatic injury induced by alcohol.

Composition and antioxidant activity of the polysaccharides from cultivated Saussurea involucrata

Polysaccharides from cultivated Saussurea involucrata (CSIP) were purified, two major fractions (CSIP1-2 and CSIP2-3) were investigated for their molecular weights, monosaccharide compositions and in vitro antioxidant activities. The results suggested that the molecular weights of CSIP1-2 and CSIP2-3 were approximately 163.5 kDa and 88.6 kDa, respectively. CSIP1-2 was composed of glucose, galactose, xylose, rhamnose, arabinose and galacturonic acid with a molar ratio of 1.651:0.39:0.062:8.331:1.759:40.426. CSIP2-3 was composed of glucose, galactose, xylose, rhamnose, arabinose and galacturonic acid with a molar ratio of 0.762:0.657:0.112:5.587:0.318:44.655. Different scavenging activities on superoxide radical, DPPH radical and hydroxyl radical were observed in CSIP1-2 and CSIP2-3 at tested concentrations.

Physicochemical and functional properties of dietary fiber from maca (Lepidium meyenii Walp.) liquor residue

Using maca (Lepidium meyenii) liquor residue as the raw material, dietary fiber (DF) was prepared by chemical (MCDF) and enzymatic (MEDF) methods, respectively, of which the physicochemical and functional properties were comparatively studied. High contents of DF were found in MCDF (55.63%) and MEDF (81.10%). Both fibers showed good functional properties, including swelling capacity, water holding capacity, oil holding capacity, glucose adsorption capacity and glucose retardation index. MEDF showed better functional properties, which could be attributed to its higher content of DF, more irregular surface and more abundant monosaccharide composition. The results herein suggest that maca DF prepared by enzymatic method from liquor residue is a good functional ingredient in food products.

Enrichment and separation of chlorogenic acid from the extract of Eupatorium adenophorum Spreng by macroporous resin

A simple and efficient chromatographic method for separation of chlorogenic acid from Eupatorium adenophorum Spreng extract was developed. The adsorption properties of nine macroporous resins were evaluated. NKA-II resin showed much better adsorption/desorption properties. The adsorption of chlorogenic acid on NKA-II resin at 25°C was well fitted to Langmuir isotherm model and pseudo-second-order kinetic model. The dynamic adsorption and desorption experiments were carried out on columns packed with NKA-II resin to optimize the separation process. The content of chlorogenic acid in the product increased to 22.17%, with a recovery yield of 82.41%.

Preliminary characterizations, antioxidant and hepatoprotective activity of polysaccharide from Cistanche deserticola

To research the preliminary characterizations, antioxidant and hepatoprotective activity of polysaccharides from Cistanche deserticola (CDPs), three polysaccharide fractions, CDP-A, CDP-B and CDP-C, were obtained by successively membrane filtration (microfiltration, ultrafiltration and nanofiltration). Molecular weights, monosaccharide compositions, purities and IR spectra of the three fractions were analyzed. Results showed that CDP-C contained higher proportion of galacturonic acid (GalUA) than CDP-B and CDP-A. Antioxidant activities were also analyzed and the results revealed that CDP-C possessed the highest activity. Thus, hepatoprotective activity of CDP-C was studied further. In vitro research, CDP-C promoted viability of HepG2 cells. In vivo research, CDP-C ameliorated the alterations induced by alcohol, including serological indexes (alanine transaminase, acid phosphatase, γ-glutamyl transpeptidase and triglyceride) and hepatic indicators (superoxide dismutase, malondialdehyde, glutathione S-transferase and triglyceride) in model animals. The prominent microvesicular steatosis and mild necrosis in hepatic histopathology of model animals were also attenuated by CDP-C administration. These findings indicated that CDP-C possessed hepatoprotective activity against chronic hepatic injury induced by alcohol. The underlying mechanism might be that CDP-C can reduce the contents of MDA and TG, and modulate the activities of the relative enzyme. This property might associate with GalUA in CDP-C.

Identification of maca (Lepidium meyenii Walp.) and its adulterants by a DNA-barcoding approach based on the ITS sequence

Maca (Lepidium meyenii) is an herbaceous plant that grows in high plateaus and has been used as both food and folk medicine for centuries because of its benefits to human health. In the present study, ITS (internal transcribed spacer) sequences of forty-three maca samples, collected from different regions or vendors, were amplified and analyzed. The ITS sequences of nineteen potential adulterants of maca were also collected and analyzed. The results indicated that the ITS sequence of maca was consistent in all samples and unique when compared with its adulterants. Therefore, this DNA-barcoding approach based on the ITS sequence can be used for the molecular identification of maca and its adulterants.