Antioxidant activities and polyphenolics content of Flammulina velutipes mushroom extracts
A study was conducted in order to determine the content of phenolic compounds and antioxidative activity of extracts from Flammulina velutipes. Water and ethanolic, methanolic, acetone (70% v/v) extracts were prepared from lyophilized fruiting bodies of mushrooms. Different extraction techniques were used: ultrasonication and stirring by a rotary shaker at ambient temperature and at 50oC, and at boiling point for each solvent. Next, total phenolics by Folin-Ciocalteu method, antioxidant capacity (EC) by ferric reducing antioxidant power assay (FRAP) and scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals were analysed in these extracts. It was observed that the extraction method and the kind of solvent influenced the antioxidant activity and concentration of total phenolics in the extracts. The highest concentration of phenolic compounds (7.58±0.17 mg GAE/g extract) were observed for water extract prepared with use of ultrasonification method (at 50oC for 1h). Results showed that water extracts possessed high equivalent capacity (EC) for all applied extraction methods. The highest EC value (9.2±0.18 mM Fe2+/g extract) was observed in water extract prepared by stirring at ambient temperature for 1 h. This extract was characterized by high level of total phenolics. The acetone extracts, prepared by ultrasonic extraction at 50oC for 1 h, at 10 mg/ml showed the highest scavenging activity (57.53±1.18%), although, the value was lower than that of ascorbic acid at 10 mg/ml (60.50±1.32%).