Abstract:

The optimal procedures for extracting total flavonoids from roots, stems, leaves and flowers of Mikania micrantha L. under the assistance of ultrasonic were studied using orthogonal array design. Besides, total flavonoids extracted were tested for hydroxyl free radical scavenging activity. Results showed that the optimal values of crucial technological parameters including ethanol concentration, solid/liquid ratio and ultrasonic working power were 50%, 1:25 and 200 W for extraction of total flavonoids from roots, 50%, 1:20 and 500 W for extraction of total flavonoids from stems, 90%, 1:20 and 500 W for extraction of total flavonoids from leaves, and 70%, 1:25 and 200 W for extraction of total flavonoids from Mikania micrantha L. flowers. There was a positive correlation between hydroxyl radical scavenging activity and concentration of total flavonoids from roots, stems, leaves and flowers of Mikania micrantha L. observed at four experimental levels, and the hydroxyl radical scavenging rates at the concentration level of 1.32 mg/mL were 33.86%, 32.58%, 38.79% and 21.84%, respectively, lower than that of BHT, a common antioxidant. Thus, Mikania micrantha L., an invasive weed, has a certain potential for exploitation and utilization due to its short growth period and abundance.

Key words: Mikania micrantha L., total flavonoids, antioxidant activity, hydroxy free radical (·OH)