Comparison of phenolics, antioxidant, and antiproliferative activities of two Hypsizygus marmoreus varieties

Phenolics, antioxidant activities, and antiproliferative properties of brown Hypsizygus marmoreus (brown HM) and white Hypsizygus marmoreus (white HM) were compared. The results showed that the contents of (+)-catechin, gallic acid, and protocatechuic acid of brown HM were higher than those of white HM. Moreover, brown HM had greater cellular antioxidant activity (CAA), peroxyl radical scavenging capacity (PSC), and oxygen radical absorbance capacity (ORAC) values than white HM, which demonstrated that brown HM presented a stronger antioxidant capacity. Both of brown HM and white HM showed remarkable antiproliferative activities against HepG2 cells and brown HM was proven to be the more effective. The flow cytometry results revealed that both of brown HM and white HM could induce G1 arrest and cell apoptotics in a dose-dependent manner. In addition, CyclinD1, CDK4, and Bcl-2 mRNA expression levels were downregulated with the treatment of brown HM or white HM. Taken together, our study revealed that brown HM afforded better antioxidant and antiproliferative activities than white HM and laid the foundation for potential application of Hypsizygus marmoreus as source of nutraceuticals and functional food products. PRACTICAL APPLICATION: A systematic assessment of the potential differences of phenolics, antioxidant, and antiproliferative activities between different Hypsizygus marmoreus varieties was carried out in the present study. Furthermore, our findings would present possible antiproliferative mechanism of extracts of different Hypsizygus marmoreus varieties, which may provide theoretical basis for further development and utilization of Hypsizygus marmoreus.

Efficient purification of antiproliferative polysaccharides from Hypsizigus marmoreus with radial flow chromatography

The increasing commercial significance of natural polysaccharides for use in medicinal products is stimulating the development of efficient and easy scale-up techniques for polysaccharide purification. In this research, the crude polysaccharides from submerged cultivation broth of Hypsizigus marmoreus were purified using radial flow chromatography (RFC), and the antiproliferative activity of the purified fractions was evaluated in vitro. DEAE Sepharose CL-6B was selected to be packed in the RFC column based on its good resolution, physical stability, and low cost. Compared with axial flow chromatography (AFC), an efficient chromatographic process with significantly less time and buffer consumption but yielding higher polysaccharide recovery and resolution was established in RFC, which could clearly purify the crude polysaccharides into different fractions. An acceptable linear scale-up effect of RFC from 100 to 500 mL was successfully achieved without loss of resolution and enhancement of time consumption. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays in cell cultures indicated that the purified polysaccharide fractions possess moderate antiproliferative activities in three different human cancer cell lines, but have significantly lower cytotoxicity in normal human cell lines in vitro. Among the polysaccharide fractions, the main purified acidic fraction W-I could be considered as a novel potential antitumor agent candidate for several tumors, especially for human alveolar epithelial tumors. This research confirmed for the first time that RFC would be a new fast and efficient tool for purification of polysaccharides into different fractions, both at laboratory and commercial scales.

Characterisation and immunomodulating activities of exo-polysaccharides from submerged cultivation of Hypsizigus marmoreus

Exo-polysaccharides were purified and characterized from the fermentation broth of Hypsizigus marmoreus, a popular edible mushroom consumed in Asia. Among them, B-I-I and B-II-I exhibited potent complement fixating activity, meanwhile, B-N-I, B-I-I, B-II-I and B-II-II exhibited significant macrophage stimulating activity. Molecular weights of the four exo-polysaccharides were determined to be 6.3, 120, 150 and 11 kDa respectively. Molecular characterisation showed that B-N-I is basically an α-1→4 glucan, with branches on C6; B-I-I is a heavily branched α-mannan with 1→2 linked main chain. B-II-I and B-II-II, have a backbone of rhamno-galacturonan with 1→2 linked l-rhamnose interspersed with 1→4 linked galacturonic acid. Structure-activity relationship analysis indicated that monosaccharide compositions, molecular weight, certain structural units (rhamno-galacturonan type I and arabinogalactan type II) are the principal factors responsible for potent complement fixating and macrophage-stimulating activities. Their immunomodulating activities may, at least partly, explain the health benefits of the mushroom.