Preparation, preliminary characterization and immunostimulatory activity of polysaccharide fractions from the peduncles of Hovenia dulcis.

The peduncles of Hovenia dulcis, containing abundant nutrients and having a taste like a combination of raisin, clove, cinnamon and sugar, have been consumed as fruits and used as traditional herbal medicine for a long time in China. Up to date, little information is available about the polysaccharides from peduncles of H. dulcis (HDPS) and their potential bioactivity. In this study, three purified fractions were prepared by sequential purification of crude HDPS through ion-exchange chromatography and gel-filtration chromatography. The three fractions of HDPS-1, HDPS-2 and HDPS-3 were found to be homogeneous heteropolysaccharides mainly composed of rhamnose, arabinose, galactose and galacturonic acid with an average molecular weight of 235, 70 and 53 kDa, respectively. HDPS-3 was quite different from HDPS-1 and HDPS-2, as it contained much higher content of galacturonic acid (40.5%). In vitro immunostimulatory activity evaluation revealed that all the three fractions could significantly stimulate the proliferation of splenocytes and enhance phagocytosis, nitric oxide production and acid phosphatase activity of peritoneal macrophages, which suggested that HDPS had a potent immunostimulatory activity and could be explored as a potential natural immunomodulatory agent.

Wang M ，Jiang C ，Ma L ，Zhang Z ，Cao L ，Liu J ，Zeng X ... -  《-》

Preliminary characterization, antioxidant activity in vitro and hepatoprotective effect on acute alcohol-induced liver injury in mice of polysaccharides from the peduncles of Hovenia dulcis.

The fresh fleshy peduncles of Hovenia dulcis have been used as a food supplement and traditional herbal medicine for the treatment of liver diseases and alcoholic poisoning for more than a millennium. The objectives of the present study, therefore, were to determine the antioxidant activity of polysaccharides from the peduncles of H. dulcis (HDPS) and to evaluate its hepatoprotective effect on acute alcohol-induced liver injury in mice. HDPS, prepared by hot water extraction, ethanol precipitation and treatment of macroporous resin, was found to be non-starch polysaccharide and mainly composed of galactose, arabinose, rhamnose and galacturonic acid. In in vitro antioxidant assay, HDPS exhibited high superoxide radical scavenging activity, strong inhibition effect on lipid peroxidation and a medium ferrous ion-chelating activity. For hepatoprotective activity in vivo, the administration of HDPS significantly decreased the serum levels of alanine aminotransferase and aspartate aminotransferase, significantly decreased the liver level of malondialdehyde and remarkably restored the liver activities of superoxide dismutase and glutathione peroxidase in alcohol-induced liver injury mice. The results suggested that HDPS had a significant protective effect against acute alcohol-induced liver injury possibly via its antioxidant activity to protect biological systems against the oxidative stress.

Wang M ，Zhu P ，Jiang C ，Ma L ，Zhang Z ，Zeng X ... -  《-》

Purification, characterization and immunostimulatory activity of polysaccharide from Cipangopaludina chinensis.

In this study, we investigated the purification, preliminary characterization and immunostimulatory activity in vivo of polysaccharide from Cipangopaludina chinensis (CCPS). Firstly, crude CCPS was prepared by hot water extraction. And the crude CCPS was sequentially purified by chromatography of DEAE-52 and Sephadex G-100, resulting in two purified fractions of CCPS-1 and CCPS-2. We found the two fractions were homogeneous heteropolysaccharides mainly composed of rhamnose and glucose with the average molecular weight of 226 and 235 kDa, respectively. CCPS-2 was quite different from CCPS-1. It had much higher content of uronic acid and sulfuric radical. For immunostimulatory activity in vivo, crude CCPS could significantly increase the thymus and spleen indices, enhance the macrophage function, and increase the level of serum hemolysin in cyclophosphamide-treated mice, suggesting CCPS had a potent immunostimulatory activity and could be explored as a potential natural immunomodulatory agent.

Xiong Q ，Jiao Y ，Zhao X ，Chen X ，Zhang Q ，Jiang C ... -  《-》

Optimization of ultrasonic extraction of polysaccharides from Hovenia dulcis peduncles and their antioxidant potential.

An ultrasonic-assisted extraction of polysaccharides from the ripe peduncles of Hovenia dulcis (HDPs) was investigated. Response surface methodology along with a Box-Behnken design based on single-factor experiments was employed to optimize and model the extraction conditions of HDPs, namely extraction temperature (40-60 °C), ultrasonic power (320-480 W) and extraction time (35-65 min). The optimized conditions were extraction temperature 60 °C, ultrasonic power 362 W and extraction time 65 min. Under these conditions, the maximal yield of crude HDPs was 25.12±0.145 mg/g DW, which is consistent with the predictive yield of 25.33 mg/g DW. The polysaccharides were graded by an ethanol precipitation method and three fractions (HDPs1, HDPs2 and HDPs3) were harvested. These had final ethanol concentrations of 40%, 60% and 80%, respectively and were acidic polysaccharides. The preliminary characterization was mainly composed of Ara, Rha, Glu and Gal, and exhibited an almost similar characteristic absorption peak by gas chromatograph and infrared spectra analysis. The antioxidant activity assays in vitro revealed that HDPs can be used as natural antioxidants in functional foods and pharmaceutical industries.

Liu Y ，Qiang M ，Sun Z ，Du Y ... -  《-》

Isolation, partial characterisation and immunomodulatory activities of polysaccharide from Morchella esculenta.

Polysaccharides extracted from fungi or algae have shown a variety of medical activities, and the exploitation of polysaccharides for application in pharmacy has been very promising. In this study, the immunomodulatory properties of polysaccharides from Morchella esculenta were investigated to identify immunostimulatory activity and potentially contribute to the therapeutic potential of Morchella esculenta. A water-soluble polysaccharide, MEP, was obtained from the fermentation broth of Morchella esculenta. Two fractions of this polysaccharide (MEP-I and MEP-II) were extracted and purified. High-performance gel permeation chromatography analysis showed the average molecular weights of two polysaccharides. Structural properties and compositions of these two fractions were examined by Fourier transform infrared and a high-performance liquid chromatography with an evaporative light scattering detector. Active experiments suggested that the MEP had typical immunostimulatory activity. These bioactivity tests showed that the polysaccharides from Morchella esculenta presented significant immune modulating activity, and this finding may offer the basis for the popular use of polysaccharides in functional foods or medicine.

Cui HL ，Chen Y ，Wang SS ，Kai GQ ，Fang YM ... -  《-》