Extraction optimization and biological properties of a polysaccharide isolated from Gleoestereum incarnatum

Extraction was optimized of polysaccharides from Gleoestereum incarnatum (GIP). The three parameters, extraction temperature, extraction time and the ratio of water to raw material, were optimized using the Box-Behnken design. As a result, the optimal extraction conditions were: extraction temperature 87.5 °C, extraction time 1 h and the ratio of water to raw material of 39.7 mL/g, where the highest yield of polysaccharide (13.18%) was obtained. GIP-II was the main fraction purified form GIP. GIP-II was composed of galactose, glucose, xylose, and mannose, with glucose was the predominant monosaccharide. GIP-II exhibited strong scavenging activities against DPPH and hydroxyl radials in vitro, as well as a strong inhibitory effect on the growth of HepG2 cells. The overall findings indicated that GIP-II is worthy of further exploration for its potential applications in antitumor drugs or health foods.