Abstract: This investigation adopted ultrasound extract to extract flavonoids in Mori barks. According to the orthogonal test, the optimum extraction conditions are: 60 mesh granularity, 80% ethanol, 325 W ultrasound power, solid/liquid ratio 1:10 and 30 min processing time with flavonoid yield 7.841‰. The antioxidant activities of flavonoid extracts were evaluated by two antioxidant assays, for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging and reducing power. In comparison with the heat reflux extraction, the results showed that the flavonoid contents and antioxidant activities of extracts obtained by two different extractions are comparable.

Key words: Mori bark, flavonoids, ultrasound extraction, antioxidant activity