Extraction Process Of Total Flavonoid From Coreopsis Tinctoria

The flower of Coreopsis tinctoria Nutt., so called Snow chrysanthemum, has beenapplied as a kind of tea flowers in Xinjiang district in China. It has some effects onlowering blood pressure, regulation of blood Lipids, blood glucose. Flavonoids are themain active ingredients within this herb, but their contents and extraction process remainnot well clarified. In this thesis, extraction process of total flavonoid from Coreopsistinctoria (CTE) was developed, as well as antioxidant assays of these extracts. Marein andflavanomarein were also selected as chemical markers for quantification of CTE.A HPLC method was established for simultaneous determination of two targetcompounds at first. A CosmosiL AR-Ⅱ-C18(4.6mm×250mm,5μm) column was applied;the mobile phase was acetonitrile (A)-0.1%acetic acid (B), with graduate elution of16%A (0-20min) followed by20%A (20-40min); a DAD was applied, with the detectionwavelengths setting at280(for flavanomarein) and378nm (for marein); the flow rate andcolumn temperature was set at1.0mL/min and30°C, respectively; and sample volumewas20μL. As a result, the linear range for marein and flavanomarein was4.124-82.48g，0.4008-8.016g, with the average recovery to be97.93%and97.64%, respectively.Samples were ultrasonic extracted using50%ethanol as solvents. Under this condition, thecontent of marein and flavanomarein of Snow chrysanthemum was determined to be129.7and20.62mg/g, respectively.Extraction process was then developed using single factor tests and following centralcomposite design tests. As an extraction solvent, ethanol ratios were demonstrated toinfluence both quantities and relative ratios of marein and flavanomarein of CTEsignificantly. To obtain highest contents of both compounds in total, the optimal extractionconditions were established as follows: extraction twice with50%ethanol solution underreflux for50Min, with material and liquid ratio of1:20(g/mL). DPPH radical and ABTSradical cleavage tests were also conducted for different CTE samples obtained from centralcomposite design tests. All CTE samples possessed strong antioxidant activities against DPPH·and ABTS·, and marein was suggested as one of the main antioxidant compounds.Some regression equations were further deduced to calculate accurate optimal extractionfactors for extraction process of certain flavonoid and and their antioxidant capaciitiesagainst DPPH·and ABTS·as well.These results are helpful for elucidation of key factors of extraction process of CTE,which are important for both quality control and further developments of Snowchrysanthemum as functional food products.