Antimicrobial and Antioxidant Activities of Extracts from Bulbs of Lycoris aurea

[Objectives] To explore the antimicrobial and antioxidant activities of flavonoid and polysaccharide extracts from bulbs of Lycoris aurea. [Methods] The disc diffusion method was used to evaluate the antimicrobial activity of flavonoid and polysaccharide extracts from the bulbs of L. aurea. The antioxidant activity was determined by scavenging of hydroxyl and 1,1-diphenyl-2-picrylhydrazine(DPPH) free radicals, and reducing ability. [Results] Flavonoids were effective on 7 microorganisms, but polysaccharides had no effect. Flavonoids had better hydroxyl free radical scavenging activity and reducing capacity than polysaccharides, but weaker than ascorbic acid. However, flavonoids had similar DPPH free radical activity to ascorbic acid. The strong antibacterial and antioxidant activities of flavonoids were mainly attributed to the high content of total phenols in the extract, which was(76.71±4.42) mg/g. [Conclusions] The study shows that flavonoids from bulbs of L. aurea could be regarded as a new potential source of natural bacterial inhibitors and antioxidants.