Studies On Determination, Purification And Bioactivities Of Flavonoids From Zhongyuan Tree Peony

Tree peony is well-known in China, is named as'Wan Hua Yi Pin'and enjoyed the honor of'The King of Flowers'. Flavonoids are a class of compounds with 2-phenyl-chromone structure in nature. They have a wide range of biological activities, among which antioxidant activity is the most important. The optimum conditions of the purification of anthocyanins from tree poney flowers were determined by the method of macroporous adsorbtion resins and the antioxidant activity of extract and anthocyanins from tree peony flower were assayed. The results were as follows:(1) Based on the UV-visible scanning spectra,through the comparison of test methods and the evaluation of test method, the direct measuring method(at 350nm) was established for the quantitative analysis of total flavonoids in zhongyuan tree peony.This method was thought to be a simple,accurate and rapid one.(2) The static adsorption behaviors on twenty-one kinds of macroprous resins were studied and the optimum kind of macroporous resin was screened in the present work. Also,the adsorption performance and desorption conditions of the proper macroporous resin for tree peony flavonoids was researched,the optimum parameters of adsorption and desorption were procured.The results showed that LS-303 macroporous resin was the optimum kind of macroporous resin among twenty-one macroporous resins under the experimental condition.The optimum conditions of dynamic by LS-303 were as follows:the proper pH value of tree peony solution was 6.0,the concentration of tree peony solution was 6.92mg·mL^-1,the flow rate was 0.72mL·min^-1,the ratio of column height to diameter was 10︰1,the eluent solvent was 60% ethanol,the eluent rate was 0.72mL·min^-1.The purity of flavonoids was increased from 12.17% to 77.01% with a recovery of 96.6% under the conditions mentioned above.(3) The antioxidant activity of the crude extracts and partial puried flavonoids of the'dazongzi'was studid in different experimental systems.The results showed that under the same concentration, the reducing power of the partial puried flavonoids was slightly lower than that of ascorbic acid but notably higher than that of rutin, meanwhile the reducing power of the crude extracts is both lower than that of ascorbic acid and rutin. Peony flavonoids has a strong scavenging capacity on DPPH·and HO·, and in certain concentration showed a good dose-effect relationship, semi-clear concentration (EC₅₀) of partial puried flavonoids, the crude extracts, Vc and rutin on the of DPPH·respectively were 80.72μg/mL, 287.74μg/mL, 81.52μg/mL and 141.45μg/mL, the reaction rate constant of partial puried flavonoids reacting with HO·was 8.521×107 L·g^-1·s^-1. In liposome oxidation system, partial puried flavonoids can inhibit liposome oxidation of liver homogenate and soybean lecithin induced by AAPH by clearing water-soluble peroxy radicals and free radical of lipid peroxidation.(4) The varieties of flavonoids in the petals of'luoyanghong'were analysed by HPLC-DAD-ESI-MS. The basic structure of eight flavonoids were shown as follows: quercetin-bioside (hexose+hexose), kaempferol-bioside (hexose+hexose), isorhamnetin-bioside (hexose+hexose), luteolin-bioside (methyl pentose+hexose), luteolin-single-glucoside (hexose), apigenin-bioside (methyl pentose+hexose), apigenin-bioside (acid hexose+hexose) and chrysoeriol-single-glucoside (hexose) . Quercetin-bioside (hexose+hexose), isorhamnetin-bioside (hexose+hexose), luteolin-bioside (methyl pentose+hexose), apigenin-bioside (acid hexose+hexose) and chrysoeriol-single-glucoside (hexose) seem to be previously unreported in tree peony.