Abstract: Objective: To evaluate and compare the antioxidant and antimicrobial capacity of polysaccharides from Auricularia cornea var. Li, Auriculari auricula, Auricularia polytricha, was determined. Methods: The polysaccharides were obtained by water extraction followed by ethanol precipitation and the polysaccharide content was determined. The total antioxidant capacity and the scavenging activity against hydroxyl, superoxide anion, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals and nitrite of the three polysaccharides were measured by spectrophotometry. Besides, the minimum inhibitory concentration (MIC) method was employed to compare the antimicrobial activity of the polysaccharides against Escherichia coli, Staphylococcus aureus and Bacillus subtilis. Results: Under the same conditions, the extraction yields of crude polysaccharides from Auricularia cornea var. Li, Auricularia auricula and Auricularia polytricha were 13.87%, 11.26% and 7.91%, respectively, and the purities of the obtained polysaccharides were 49.22%, 41.50% and 37.97%, respectively. Among these, Auricularia polytricha polysaccharides had the highest total antioxidant capacity, while the antioxidant activities of the two other polysaccharides were lower and similar to each other. The hydroxyl radical scavenging capacity of Auricularia cornea var. Li polysaccharides was slightly stronger than that of Auricularia auricula, although both of them showed similar superoxide anion radical scavenging activity, which was stronger than that of Auricularia polytricha polysaccharides. Moreover, all three polysaccharides exhibited potent DPPH radical scavenging capacity with an inhibition percentage of 80% with Auricularia cornea var. Li polysaccharides being the most effective. Auriculari auricular polysaccharides had slightly higher nitrite scavenging capacity than the other polysaccharides. All these polysaccharides had an inhibitory effect on Escherichia coli, but Auricularia polytricha and Auricularia auricula showed weak inhibitory effect on Staphylococcus aureus or Bacillus subtilis. Only Auricularia cornea var. Li. polysaccharides presented a marked inhibitory effect on both Staphylococcus aureus and Bacillus subtilis. Conclusion: The polysaccharides from three Auricularia species have significant differences in antioxidant and antibacterial capacity.

Key words: Auricularia cornea var. Li polysaccharides, Auricularia auricula polysaccharides, Auricularia polytricha polysaccharides, antioxidant activity, antimicrobial activity