Study on the extraction and antioxidant activity of total flavonoids from Netted melon with ultrasonic

The single factor and orthogonal tests were designed to study the perfect conditions of extracting total flavononids from Netted Melon and the antioxidant activity of the extract. Firstly, the best conditions of extracting total flavononids from Netted Melon by single factor and orthogonal test was: ultrasonic power was 60%(250W),concentration of ethanol was 90%(V/V), extraction time was 60min,volume of ethanol was 25mL. Under these conditions, the extraction yield of flavonoids was 0.2247 mg/g, which was 88.43% of the result of soxhlet, while, the time was 25% of soxhlet, from which the work efficiency was greatly improved. Then Prussian blue, Pyrogallol autoxidation, Phenanthroline and DPPH were used to research the antioxidant activity of flavonoid. It shows that flavonoid of Netted Melon can remove DPPH and hydroxyl radical strongly, also it has reducing capacity, but it's ability of oxygen radical scavenging is poor.