Extraction And Purification Of Flavonoids Of Houttuynia Cordata Thunb.

The preparations made of the volatile oil of Houttuynia cordata Thunb. are definite in treatment for respiratory diseases, digest system inflammatory diseases and so on. Flavonoids are another main kind of effective components in Houttuynia cordata Thunb.. On the base of supercritical CO2 extraction of volatile oil from Houttuynia cordata Thunb., extraction and purification of flavonoids in this medical plant were studied in this paper, on one hand to make full use of the medical plant and on the other hand to be the base of new medicines and health products development.First, the RP-HPLC method was established to determine the 4 kinds of flavonoids i.e., rutin, hyperin, quercitrin and quercetin in Houttuynia cordata Thunb.. Presicion, repeatability, stability investigation and recovery tests were carried out. This method can be a reference for the quality control of the processes and the products.In the extraction process, supercritical carbon dioxide was firstly used to extract the volatile oil from Houttuynia cordata Thunb. under the optimized conditions established by the former research in our lab. The remains were used as the material to extract the flavonoids with carbon dioxide combined with aqueous ethanol under high pressure. Orthogonal experiment was carried out to investigate the influences of several important factors such as the concentration of ethanol, solvent flow, temperature and pressure. Both a high flavonoids yield of 3.15% and a high flavoniods content of 23.96% were obtained under the optimized conditions. The results are obviously favorable to that of hot soaking and ultrasound-assisted extraction.In the purification process, macroporous resin adsorption technology was used to purify the crude flavonoids. Nine kinds of macroporous resins with different properties were tested through static adsorption, where, one macroporous resin named as D101 was selected for further investigation. The effect of several factors such as the ratio of column height to diameter, initial concentration and pH value on both flavonoids yield and content were explored in dynamic adsorption process to obtain reasonable conditions of adsorption and desorption. The optimum experimental results show that, the recovery is 93.27% and the content of flavonoids can be about 67.40%, which is obviously higher than what was reported.The studies of dynamics and thermodynamics of D101 were also performed, which can serve as the basic data and reference for the purification process.