Effect of extraction method on structure and antioxidant activity of Hohenbuehelia serotina polysaccharides.

The impacts of four extraction methods (hot water, enzyme assistance, ultrasonic assistance and ultrasonic-enzyme assistance) on the extraction yields, preliminary structure and antioxidant activities of the Hohenbuehelia serotina polysaccharides (HW-HSP, EA-HSP, UA-HSP and UEA-HSP) were systematically investigated. The yield of the polysaccharides (20.70±0.17%) obtained by ultrasonic-enzyme assistance was higher than the polysaccharides by other methods'. Four kinds of polysaccharides possessed the different preliminary structural characteristics including molecular weight distributions, monosaccharide compositions, crystallization and spiral structures, while different surface morphology. Through the measurements of antioxidant activities in vitro, UEA-HSP exhibited the most significant scavenging capacities on non-physiological ABTS free radicals and physiological hydroxyl radicals. These data showed that ultrasonic-enzyme assistance was more beneficial to enhance the extraction yields of the polysaccharides, and obtain higher bioactive polysaccharides. The results also suggested that H. serotina polysaccharides possessed potential healthcare application in food field due to their antioxidant activities.

Li X ，Wang L 《-》

Synthesis, characterization and antioxidant activity of selenium modified polysaccharides from Hohenbuehelia serotina.

In order to search the optimal pathway to supplement organic selenium and solve the water-solubility of polysaccharides, selenylation was preformed to modify the polysaccharides isolated from Hohenbuehelia serotina (Se-HSP). The physicochemical properties and morphology of Se-HSP were investigated by UV-visible spectrometry, Fourier transform infrared spectrometry (FT-IR), X-ray diffraction spectroscopy (XRD), Circular dichroism spectroscopy (CD), scanning electron microscope (SEM) and atomic force microscope (AFM), respectively. The results suggested that selenium was successfully bound to HSP by esterification reaction. Se-HSP was a non-crystalline substance with the lump structure and smooth and dense surface. The height of Se-HSP was distributed in the range of 35-106 nm. In vitro antioxidant determinations found that Se-HSP possessed the similar/more significant scavenging capacities on ABTS, hydroxyl and superoxide anion radicals as/than the ability of HSP. The present data indicated that selenylation modification could not change the antioxidant activities of HSP in vitro, which also suggested that Se-HSP could serve as a potential antioxidant agent to be used as selenium-complementary nutraceutical.

Wang L ，Li X ，Wang B 《-》

Ultrasonic-assisted extraction of polysaccharides from Hohenbuehelia serotina by response surface methodology.

An ultrasonic-assisted procedure for the extraction of polysaccharides from the fruiting body of Hohenbuehelia serotina was investigated using response surface methodology. The effects of four factors on the yield of polysaccharides were studied. The optimized conditions were extraction temperature 94 °C, extraction time 3.0 h, ratio of water to raw material 110:1 and ultrasonic power 480 W. Under these conditions, the experimental yield of polysaccharides was 17.45±0.18%, which was well matched with the predictive yield of 17.54%. The molecular weight of polysaccharide was ranged from 1.19 × 10³ to 1.55 × 10⁴ Da. The polysaccharides were composed of ribose, arabinose, mannose, glucose and galactose in a ratio of 0.65:0.69:9.35:14.24:5.47. Then, the structural features of untreated materials, hot water extraction residue and ultrasonic-assisted extraction residue were compared by SEM. Results indicated that ultrasonic-assisted extraction technology could be an effective and advisable technique.

Li X ，Wang Z ，Wang L ，Walid E ，Zhang H ... -  《-》

Effects of extraction methods on the antioxidant activities of polysaccharides from Agaricus blazei Murrill.

Five polysaccharides were obtained from Agaricus blazei Murrill (ABM) through different extraction methods including hot water extraction, single enzyme extraction (pectinase, cellulase or papain) and compound enzymes extraction (cellulase:pectinase:papain). Their characteristics such as the polysaccharide yield, polysaccharide content, protein content, infrared spectra were determined, and antioxidant activities were investigated on the basis of hydroxyl radical, DPPH free radical, ABTS free radical and reducing power. The results showed that five extracts exhibited antioxidant activities in a concentration-dependent manner. Compared with other methods, the compound enzymes extraction method was found to present the highest polysaccharides yield (17.44%). Moreover, compound enzymes extracts exhibited the strongest reducing power and highest scavenging rates on hydroxyl radicals, DPPH radicals and ABTS radicals. On the contrary, hot water extraction method had the lowest polysaccharides yield of 11.95%, whose extracts also exhibited the lowest antioxidant activities. Overall, the available data obtained in vitro models suggested that ABM extracts were natural antioxidants and compound enzymes extraction was an appropriate, mild and effective extracting method for obtaining the polysaccharide extracts from Agaricus blazei Murrill (ABM).

Jia S ，Li F ，Liu Y ，Ren H ，Gong G ，Wang Y ，Wu S ... -  《-》

Physicochemical properties and activities of comfrey polysaccharides extracted by different techniques.

The effects of extraction techniques on the physicochemical properties, antioxidant activity and antihyperglycemic activity of comfrey polysaccharides (CPs) were evaluated. Four techniques were used to extract CPs: hot water extraction (HW), ultrasonic-assisted extraction (UA), enzyme-assisted extraction (EA) and enzyme-ultrasonic-assisted extraction (EUA). Experimental results indicated that CPs extracted by the UA (UA-CPs) and EUA methods (EUA-CPs) had higher extraction yields. The four CPs showed the same monosaccharide composition but a significant difference in monosaccharide content. CPs showed antioxidant activities and antihyperglycemic activities in a concentration-dependent manner. UA-CPs exhibited better antioxidant capacity, which might have been related to its smaller molecular weight and higher uronic acid content. In addition, UA-CPs showed notable α-glucosidase inhibition activity. These results suggested that ultrasonic-assisted extraction technology was more beneficial to enhance the extraction yields of the polysaccharides, and obtain higher bioactive polysaccharides from comfrey.

Duan M ，Shang H ，Chen S ，Li R ，Wu H ... -  《-》