Extraction and antioxidant activity of Ganoderma lucidum polysaccharides using electrolyzed oxidizing water

The fruiting body of Ganoderma lucidum (Ling Zhi) is a traditional medicinal mushroom for promoting health and life expectancy. G. lucidum polysaccharides (GLPs) has several biological activities, including antioxidant, antitumor, antimicrobial and increase the immunity. In order to extract GLPs, electrolyzed oxidizing water (EOW)was used to accelerate their dissolution from the cell walls. Compared to traditional extraction method, electrolyzed oxidizing water is an environment friendly and economically feasible method. The extraction conditions including time, temperature, pH and water-to-solid ratio were optimized by single factor experiments followed by an orthogonal experiment, for maximising total sugar content and antioxidant capacity. The optimal extraction time, temperature, EOW pH and water-to-solid ratio were 4 h, 100°C, pH 2.5 and 20 mL/g, respectively, which yielded 78.47 ± 2.95 mg/g of GLP. The extracted GLP exhibited strong antioxidant effects, including scavenging ofDPPH• and HO•, with IC₅₀ values of 0.55 mg/mL and 0.76 mg/mL, respectively.