Extraction and separation of flavonoids from Houttuynia cordata Thunb. Leaves

The microwave-assisted extraction technique for flavonoids from Houttuynia cordata Thunb. leaves was studied, and the optimization of technological parameters were obtained by orthogonal experiments. At the same time, seven types of macroporous resin were selected to compare their performances in absorbing and desorbing flavonoids from Houttuynia cordata Thunb. leaves. The optimal macroporous resin was decided at last and its dynamic absorbing and desorbing behavior was studied. Results show that the optimum conditions are as follows: ethanol concentration is 50%, the ratio of solid to liquid is 1︰50(w/v), dipping 30 min, microwave action time is 30 s and microwave power is 540 W. Compared with traditional ethanol extraction, microwave-assisted extraction is able to reduce the extraction time from 3 h to 30.5 min and increases extraction rate from 92.14% to 95.93%. And NKA-9 type macroporous resin possesses higher absorption and desorption capacity. The optimum technological parameters of adsorption and separation are pH 3.00～3.50, velocity of flow 1 mL/min and sample solution concentration 2.21～3.10 mg/mL. When 70% ethanol is used as eluant, the desorption capacity is 97.8%, and 3BV eluant can desorb flavonoids from Houttuynia cordata Thunb. leaves basically.