Pleurotus tuber-regium polysaccharide and extraction method thereof

The invention belongs to the fields of extraction, separation and purification of natural products and discloses pleurotus tuber-regium polysaccharide and an extraction method thereof. The method comprises the following steps: adding water into pleurotus tuber-regium dry powder for ultrasonic extraction for 2-4 hours; centrifuging; concentrating by using a rotary evaporator; hydrolyzing by using papain; deproteinizing by using a Sevag reagent; carrying out alcohol precipitation by using 95% ethanol in volume; re-dissolving polysaccharide in distilled water; ultra-filtering by using an ultrafiltration membrane and collecting components which are over 10000 Dalton; then, carrying out Sephadex G-100 column chromatography to obtain purified polysaccharide; and collecting the polysaccharide component and freeze-drying to obtain the pleurotus tuber-regium polysaccharide. By adopting the extraction method, the product is high in yield and good in purity; the yield of pleurotus tuber-regium polysaccharide is 1.8% and the purity of the polysaccharide is 91.2%; and the polysaccharide mainly comprises 44.2% by mass of glucose and 40.0% by mass of galactose.