Identification, Nutrient Composition, and Evaluation of a Wild Pleurotus citrinopileatus Strain (X21156) from Tibet for Antioxidant and Cytotoxic Activities

A fungal strain (X21156) collected in Tibet was used as the material, identified based on its morphological characteristics and internal transcribed spacer (ITS) sequence; its optimal culture conditions were analyzed by single-factor experiments; artificial domestication and cultivation were carried out; its nutrient composition was determined; and the bioactivities of its polysaccharides were detected using chemical antioxidant assays and MTT assays. The results showed that the strain was Pleurotus citrinopileatus Sing. Its optimal culture conditions were a pH of 7, a temperature of 25 °C, glucose (20 g·L−1) as the carbon source, and yeast powder (20 g·L−1) as the nitrogen source. The fresh weight of a single domesticated fruiting body was 41.16 g. The strain had high protein (28.5%), high fiber (34%), and low fat (1.4%) contents, with high proportions of fresh and sweet amino acids. Polysaccharides had good scavenging ability on ABTS+, DPPH, and OH free radicals (EC50 0.06 mg/mL, 1.21 mg/mL, and 3.62 mg/mL, respectively), and the cytotoxicity of polysaccharides to hepatocellular carcinoma cells (HepG2) (IC50: 1.69 mg/mL) was higher than that of triple-negative breast cancer cells (MDA-MB-468) (IC50: 1.76 mg/mL). In conclusion, the study provides a reference on the optimal culture conditions, domestication and cultivation, and dietary and medicinal values of wild P. citrinopileatus Sing.