Microwave-Assisted Extraction Optimization, Solubility, and Bioactivity Evaluation of Polysaccharides from Broken Lingzhi or Reishi Medicinal Mushroom Ganoderma lucidum (Agaricomycetes) Spore Powder

One of the main active components of broken Ganoderma lucidum spore powder was polysaccharide (BGSPP), but the extraction time was long, and the yield was low at present. Therefore, the extraction and activity of BGSPP were studied in this paper. Microwave-assisted extraction of BGSPP was designed by single factor experiment combined with a response surface methodology. Scanning electron microscopy and the 2020 edition of the Pharmacopoeia of the People's Republic of China method were used to examine the morphological characteristics and solubility of BGSPP, respectively. The monosaccharide composition of BGSPP was analyzed by high-performance liquid chromatography (HPLC). Its activities were antioxidant and hypouricemic in vitro. The results of the optimum conditions of BGSPP were temperature of 90°C, power of 400 W, time of 16 min, liquid-solid ratio of 20:1 mL/g, and extracted twice. The extraction yield, purity, and solubility were 2.57 ± 0.03%, 59.63 ± 0.11%, and 37.13 ± 0.20 mg/mL, respectively. The BGSPP extracted by the two methods had the same composition, but the molar percentages of its composition differed. The IC50 values of DPPH, ABTS+ and hydroxyl radicals were 1.31 ± 0.02 mg/mL, 0.75 ± 0.01 mg/mL and 5.30 ± 0.08 mg/mL, respectively. The IC50 value of hypouricemic activity was 14.05 ± 0.11 mg/mL. The extraction yield, solubility and activities were better than those of hot reflux extraction. In conclusion, the extraction process is stable and efficient has been found to have a hypouricemic activity, which provides a scientific basis for the development and utilization of BGSPP.