.BETA.-Glucans in the Water-insoluble Residue of Hericium erinaceum

Abstract

Fruiting bodies of Basidiomycetes mushrooms have been attracted increasing attention of pharmaceutical and functional food industry because of their health promotion and disease alleviation effects on human health. 1) On account of bioactive and medicinal activities, immune stimulation, anti inflammatory antimicrobial, antitumoral, hepatoprotective, cholesterol lowering properties are representative as well as antifibrotic, antidiabetic and hypoglycemic activities.2 6) The origin of these effects are best known to be derived from polysaccharides belonging to β glucans. Recently, the importance of β glucans contained in the mushrooms was reviewed by several authors. 1,7)The fruiting body of Hericium erinaceum called Yamabushitake in Japan is growing much attention as a source of β glucans based on recent success of commercial availability. Mizuno et al . reported that β glucan from H. erinaceum had antitumor activity. 8) We are, therefore, interested about β glucans in H. erinaceum and previously reported about extractability of β glucans from its pulverized fruiting body by using microwave heating in water.9) The results showed that only 22.0% of β glucans were extracted by this treatment. The reason of this low extractability of β glucans may be due to their complex distribution in cell wall.In the case of Schizophyllum commune, three types of glucan were present in the multi layered cell walls; (1 3) β D glucan with branches of single glucose units attached by (1 6) linkages in the outer layer, (1 3) α D glucan in the middle layer and covalently linked chitin (1 3;1 6) β D glucan complex in the inner layer. 12) Our previous results further showed the presence of water soluble (1 3;1 6) β D glucan extractable by microwave irradiation in water 9) and alkali soluble (1 3;1 6) β D glucan having (1 6) linked branch points at every five (1 3) linked glucose residues.13) Use of alkali was shown to be effective for extraction of glucans amounting to 42.3% of the total quantity in H. erinaceum. However, since substantial amount (35.7%) of glucan is still remained in the alkali extracted residue, development of method for extraction of whole β glucans and characterization of their chemical structures are necessary for utilization of H. erinaceum as an origin of β glucans in future.In this study, an effective procedure to extract β glucan from the residue given after microwave irradiation in water was developed by stepwise treatments with alkali, enzyme microwave irradiation followed by re extraction with alkali, taking the multi layered cell wall structure into consideration.In addition, since alkali split hydrogen bonds connecting mainly hydroxyl groups in the cell wall of H. erinaceum to solubilize β glucans, urea which was known as a strong hydrogen bond disrupting reagent 14) could be used as an extraction reagent alternative to alkali. Therefore we tried to use 8 M urea as an extraction solvent for β glucan and structure of the extracted material was compared to that of alkali extracted materia1, in order to get in...

Hesperidin from citrus peel waste: extraction and its health implications

“…Also, during microwave heating, disruption of weak hydrogen bonds occurs due to dipolar rotation of molecules. It accelerates the rupture of cells leading to a sudden rise in temperature and buildup of internal pressure inside the cell walls of plant tissue (Ahmad and Langrish, 2012;Ookushi et al, 2006Ookushi et al, , 2008aOokushi et al, , 2008bTsubaki et al, 2009Tsubaki et al, , 2010Xiao et al, 2009). Sun et al (2007) have employed a MAE process for extracting hesperidin from Pericarpium citri reticulate (dried pericarp of the ripe fruit of C. reticulate) using 70% aqueous methanol as a solvent and the results showed that MAE is an efficient, fast, and energysaving method.…”

Antioxidant Activities and Prebiotic Activities of Water-Soluble, Alkali-Soluble Polysaccharides Extracted from the Fruiting Bodies of the Fungus Hericium erinaceus

“…Due to different preparation methods, the structure, molecular weight, and other properties of the resulting Hericium erinaceus polysaccharides can also vary greatly. In terms of solubility, are they mainly water-soluble and alkali-soluble, in terms of molecular weight, their order of magnitude is in the range of 105-106, and in terms of structure, they mainly consist of β-(1→3) and β-(1→6)-glycosidic bonds, in which the molar ratio of the two types of glycosidic bonds differs greatly [22][23][24][25][26]. The significant structural differences in the β-glucan of Hericium erinaceus can be used as an ideal representative of the β-glucan of edible bacteria, providing a good model for studying the effect of different preparation methods and different structures on the regulation of the species structure of human fecal intestinal flora.…”