Antioxidant activity of flavone with different solvent extracts from Premna microphylla Turcz leaves

The article mainly evaluated the antioxidant ability of total flavonoids in various extracts ( ethyl alcohol, ethyl acetate, normal butyl alcohol, chloroform fraction and water) from Premna microphylla Turcz leaves in Jiangyou area including DPPH radical, ABTS+· radical, hydroxyl radical, superoxide anion radical scavenging effect, reducing power, ferrous ions chelating activities and total antioxidant capacity ( FRAP) . The free radical scavenging activity of total flavonoids extracted by different concentrations of ethanol was highest in DPPH. The free radical scavenging activity ( DPPH radical, ·OH, ABTS+·) , total antioxidant capacity ( FRAP) and reducing power were dependent on the concentration of alcohol increasing first and then decreasing, while the superoxide anion radical scavenging activity was contrary to the increase of alcohol concentration. The comprehensive evaluation index ( APC) of tested samples was decreased in the following order: 75% ethanol extract > 65%ethanol extract > 55% ethanol extract > 85% ethanol extract > 95% ethanol extract. The DPPH radical scavenging activity, FRAP value and reducing power were higher than those of other solvent extracts.The superoxide anion radical scavenging rate of ethyl acetate extract was stronger than those of other solvent extracts. The antioxidant capacity of ethyl acetate extract was strongest according to the APC results.The flavone from leaves of Premna microphylla Turcz has strong antioxidant activity and can be used as antioxidant or raw materials of healthy food.