Extraction of Quercetin from Houttuynia Cordata Thunb and Its Content Determination

The quercetin was extracted from Houttuynia cordata Thunb by ultrasonic extraction.Through single factor experiment and orthogonal experiment,the optimal extraction conditions were obtained as follows: extraction temperature 80℃,extraction time 45min,ethanol volume fraction 80%.Furthurmore,the contents of quercetin extracted under above optimum conditions in different parts of Houttuynia cordata Thunb from different sources were determined and compared.The results showed that the quercetin contents from different sources of Houttuynia cordata Thunb had a big difference,and the content of quercetin in leaves was obvious higher,which was 6~17times of that in roots.The HPLC method had high precision and good reproducibility, which could be regarded as a reasonable method for determining quercetin content in traditional Chinese herbs.