Study On The Process Of Extraction And Separation Of Flavonoids From Houttuynia Cordata Thunb

Houttuynia cordata Thunb is rich in flavonoids compounds, which can be used for reducing lipid, antithrombotic, anti-oxidative, anti-senile, antiarrhythmic, anti-neoplasm, anti-allergy and preventing dental caries. However, some problems still exist in the flavonoids extraction and separation processes, such as the low extraction yield, the high flavonoids lose and the low flavonoids content after purification. Therefore, it is meaningful to seek an appropriate process to extract, separate and purify the total flavonoids from Houttuynia cordata Thunb.In the extraction stage, three general methods of extraction of total flavonids from Houttuynia cordata Thunb., ultrasound assisted extraction, hot ethanol refluxing extraction and hot water refluxing extraction were investigated, in which hot water refluxing extraction was considered as a reasonable extraction method.In the clarification stage, the clarification effects of three general clarification techniques, water extracting-alcohol precipitating, high-speed centrifugation and ZTC1 + 1 natural clarifier clarification were investigated and the optimal clarification conditions of each technique were obtained. The advantages and diadvantages of the three clarification techniques were also discussed.The adsorption of total flavonoids onto macroporous resin in a column was further studied experimentally. The purification effects of eight kinds of resins with different polarity (nonpolar resin D-101, X-5, NKA, ADS-21, weak polar resin AB-8 and polar resin ADS-21, NKA-9, S-8) were firstly studied according to sorption rate, sorption capacity, desorption rate and selectivity, and the D-4020 was selected. The column experiments were then performed to determine the sorption capacity and breakthrough volume at different bed lengths, feed concentrations and feed flow rates and the optimal operation conditions were obtained. The flavonoids with a content of 72.80% could be obtained. The results were much better than those in literatures.The adsorption isotherm of flavonoids onto D-4020 was experimentally studied. The calculated results indicated that the experimental data were well fitted to the Langmuir model. Additinally, the mass-transfer process of flavonoids onto macroporous resin in fixed bed was studied. The breakthrough curve was well simulated by nonlinear fitting and the calculated overall mass-transfer coefficient was 9.69×10-4s-1. It provided a method calculating the mass-transfer coefficient for flavonoids onto D-4020.