Abstract:

The extraction technology of total flavonoids from stem of Wedelia trilobata L. and its oxidation resistance were investigated. The results showed that the optimum extractant, liquid-solid ratio, temperature, ultrasonic wave power, ultrasonic wave treated time for extraction are 70% ethyl alcohol, 1:25, 50 ℃, 210 W and 20 min, respectively, and the obtained total flavonoids content from stem is 4.1%. Moreover, with three mass concentration gradients, the average maximum clearance rates of the extract to ·OH and O2· are 20.16% and 41.59% respectively, especially its maximum inhibitory rate to H2O2 reaches 55.22%. With the storage time extending, the high concentration extract can more significantly reduce the autoxidation speed of lard. However, there is significant difference of antioxidant activity between common antioxidant BHT and the total flavonoid extract.

Key words: Wedelia trilobata L., total flavonoids, antioxidant activity