Antioxidant activity of secondary metabolites and mycelium extracts of endophytic fungi isolated from Astragalus monadelphus

13 strains of endophytic fungi were isolated from Astragalus monadelphus. The radical scavenging activity assay of secondary metabolites and mycelium extracts from these strains were investigated. Results showed that secondary metabolites and mycelium extracts from these strains had significant antioxidant activities. Reducing ability of H401 strain mycelium extracts were stronger than the ethyl acetate extract parts, and its EC50 value was 0.0034 mg/mL. Ethyl acetate parts of H802 strain exhibited strong center dot OH scavenging effect, the IC50 value was 0.0384 mg/mL. the DPPH radical scavenging activity test indicated that endophytic fungi can be a good source of radical scavenger. Besides, the compounds extracted from H401 secondary metabolites belong to beta-sitosterol based on the results of NMR analysis and literature data.