Preparation And Antioxidant Capacities Of Total Flavonoid From Coreopsis Tinctoria

The flower of Coreopsis tinctoria N utt.(Snow chrysanthemum), has been applied as tea in Xinjiang district in C hina. It has some effects on lowering blood pressure, regulation of blood Lipids, blood glucose. Flavonoids are the main active ingredients wit hin this herb, but their contents within this herb and extraction process remain not well clarified. Previously, extraction process of Snow chrysanthemum has been developed using single factor tests and following central composite design tests. In this thesis, preparation process of total flavonoid from Coreopsis tinctoria(CTTF) was further developed. Antioxidant assays of this extract were then assayed, together with marein and flavanomarein as its main ingredients. These investigations may provide important clues for research and further development of Snow chrysanthemum as potential functional foods.A preparation method of CTTF was developed at first using macroporous resin chromatography. Separation characteristics of four types of macroporous resins, D101, AB-8, LX-17 and XDA-8 were critically evaluated. Dynamic absorption/desorption experiments revealed that AB-8 possessed better separation properties. The optimal process parameters were developed as follows: Snow chrysanthemum were extracted twice with 50% ethanol solution(20 fold volume) under reflux for 60 Min, condensed to final concentration of 0.5 g/ml as counted by material amount, uploaded to a AB-8 column(bed volume, BV) and eluted with water(4 BV) followed by 10%(4 BV), 75%(5 BV), 95%(2 BV) ethanol successively, and 75% ethanol elute were collected, condensed and dried to give final C TTF extract. Two main ingredients, marein and flavanomarein were also separated and identified from CTTF, using LX2000 resin, C-18 reverse phase silica and Sephadex LH-20 columns. The content of flavanomarein and marein in CTTF was determined to be 55.30 and 35.73 mg/g, respectively by HPLC analysis. The content of total flavonoid in CTTF was determined to be 58.95% by UV-Vis method, using rutin as reference substance.Antioxidant capacities of CTTF were further assessed by 2,2-diphenyl-1-picrylhydrazyl radical(DPPH●) and 2,2′-azinobis-(3-ethylbenzothiazoline- 6-sulphonate) radical cation(ABTS●+) scavenging assays, together with its two main ingredients and rutin. They all possessed notable concentration-dependent antioxidant activities. By comparisons of their half inhibition concentration(IC50, mg/ml) data, the order of the antioxidant activity against DPPH● was as follow: marein(6.84) ﹥rutin(7.72) ﹥CTTF(19.8) ﹥flavanomarein(30.4); the order of the antioxidant activity against ABTS●+ was C TTF(45.1) ﹥rutin(69.1) ﹥marein(92.6) ﹥flavanomarein(117.5). CTTF showed strong capacities as that of rutin, with marein, flavanomarein and other flavonoids as its bioactive ingredients.