| Helianthus tuberosus L., commonly kown as Jerusalem artichoke, an perennial plant, was an Angiosperm of the Compositae family. It was originated from North America, introduced to Europe in the17th century and then to China. Many kinds of chemical component were found in the leaves, they were mainly phenolic compounds and sesquiterpene compounds.Of all the components in the leaves, flavonoids was the most physically active one. Flavonoids showed biological activities in anti-bacterial, phlogistic, detoxification, anti-bacterial, antimutagenesis, liver-protective, antioxidant, which promising a prospect for future development.In recent years, studies about flavonoids focused on the extraction, separation, content measurement and medical function in gingko, earthnut and some other plants, but there were fewer reports about flavonoids in Jerusalem artichoke. The research improved the method about the measurement of flavonoids in Jerusalem artichoke leaves by NaN02Al(NO3)3method, optimized the extraction methods, separated the flavonoids by macroporous resins, and evaluated antioxidant activity.1. Method development of flavonoids in Jerusalem artichoke leaves by NaN02Al(NO3)3-NaOH colorimetry. Rutin as the standard material, a certain amount of extract in a volumetric flask, with the corresponding diluted with2mL5%NaN02in solution, shake well, add2mL10%of Al(NO3)3, stand for6min and then add10mL of4%NaOH, shake well with the corresponding solvent volume to50mL, immediately anlysis at510nm in the UV spectrum. The method is simple, fast, accurate, and can be used for determination of total flavonoids in the Jerusalem artichoke leaves. Based on the established method, determination of the flavonoids content in different varieties and different parts of Jerusalem artichoke in Dafeng, Daqing area, were conducted. And the determination of flavonoids in Nanyu No.1of Dafeng area in different growth stages and different salt content of soil were conducted.The results show that:the total flavonoids accumulated over time, and had a slight decline in the late time. Of salinity on the accumulation of Jerusalem artichoke total flavonoids, total flavonoids content was gradually increased with increasing soil salinity, but when too high inhibited the accumulation of total flavonoid content The flavonoids content in Nanyu No.1of Dafeng area was higher than that of others. The flavonoids content in Jerusalem artichoke from Daqing area was higher than from Dafeng area. Nanyu No.1in Daqing area had the highest flavonoids content. The test results showed varietal differences, growth period differences as well as ecological differences of flavonoids content in Jerusalem artichoke (Helianthus tuberosus L.) leaves. The study provided evidences for future exploitation on Jerusalem artichoke leaves utilization.2. The antioxidant properties were investigated by O2-·,·OH and DPPH radical scavenging activities. The results of Jerusalem artichoke leaves flavonoids extract on superoxide anion radicals, hydroxyl radical, DPPH free radical determination and determination of reducing power, showed that Jerusalem artichoke leaf flavonoids have antioxidant capacity. The50%inhibition rate of Jerusalem artichoke leaves flavonoids on O2-·,·OH and DPPH radical with IC50was146.7μg/mL,132.3μg/mL,76.1μg/mL.3. The extraction technology of flavonoids from Helianthus tuberosus leaves was studied by discussing the effects of extraction methods, extraction reagents, extraction temperature, time, and the ratio of material/solution on the content of flavonoids. Based on the single factor experiments, the extraction technology of flavonoids from Helianthus tuberosus leaves was optimized by orthogonal design. The optimal technology were:reflux extraction,70%methanol concentrations as extraction reagent,80℃extraction temperatures,2h extraction time and the ratio of material/solution was1:30. The results provided scientific basis for flavonoids extraction from Helianthus tuberosus leaves.4. The separation technology was studied by macroporous resins. The static adsorption rate and desorption rate were examined to determine the better resin. The research discussed the influence of adsorption rate by sample concentration, pH and flow rate, and the effects of desorption rate by ethanol concentration and elution rate. D101showed both better static adsorption rate and desorption rate. The optimum adsorption conditions were:1.0mL/min as the flow rate,3.6mg/mL as the flavonoids concentration and pH5-6. And the optimum desorption conditions were:70%apueous ethanol and2.0mL/min as the elution rate. Flavonoids can almost be washed down by5BV ethanol elution. |
PDF Full Text Request