The Research Of Quality Control Of Soluble Yeast Glucan

Soluble yeast glucan,a kind of biomacromolecule,displays numerous biological activities including immuno-enhancement,antioxidant,growth promotion and so on,and it was widely used in drug discovery and development.In this study,alkaliinsoluble yeast glucan was extracted by the acid-alkali treatment for the first time In order to obtain better solubility of the alkali-insoluble yeast glucan and enhance its therapeutic effect in vivo,chemical modification of the alkali-insoluble yeast glucan was optimized with orthogonal test.It was very important to define for us that what the specified range of molecular weight responsible for the strongest biological activity was.Then,the content of soluble yeast glucan distributed in the range was monitored to warrant quality control of the soluble yeast glucan.Based on the above strategy,a rapid and reliable analytical method was established for determining relative molecular weight and degree of dispersion of the soluble yeast glucan using GPC technology in the present study.This approach proved good accuracy,repeatability and stability.Meanwhile,the standard curve of content determination was established by adopting sample polysaccharide composed of the similar monosaccharide and approximate average molecular weight to the soluble yeast glucan as standard samples.It was found that,compared with phenol-vitrolic colorimetry method,the GPC technology has obvious advantage in determining the content of the soluble yeast glucan with specified range of molecular weight.To confirm standards of quality control of soluble yeast glucan,the scavenging rate of DPPH free radicals,superoxide radicals and hydroxyl radical was assumed as the index of antioxidant activities.Among some different samples prepared with different extraction process,the comparative analysis of antioxidant activities and the corresponding molecular weight was performed..It was apparently observed that.antioxidant activity was closely associate with molecular weight of the soluble yeast glucan.Further investigations indicated that the weight-average molecular weight(about 30000),the number-average molecular weight(about 12000),the peak value molecular weight(about 26000)and the degree of dispersion(less than 2.5)of soluble yeast glucan were the prerequisites for guaranteeing the high biological activity.In conclusion,quality control of soluble yeast glucan was achieved by means of monitoring the content of its dissolved glucan distributed in a specified range of molecular weight and dominated the best antioxidant activity.