Studies On The Extraction, Separation, Identification And Antioxidative Function Of Reed Leaf Flavonoids

Reed (Phragmites communis Trin) blongs to Phragmites of Gramineae, which has the feature of strong growth ability and large area distribution. Because of containing several biological active materials, such as flavonoid, Reed leaf has certain medical function. Modern scientific researeh have confirmed that flavonoids have different biological activities, which can prevent and cure many diseases, so reed leaf flavonoids has a great perspective research and develop future.This project,using reed leaf as the object, by extracting and separating, purifying, and the antioxidant activity identification, got the following main results.1.When the concentration of ethanol was 70%, the optimized extraction conditions of flavonoids from reed leaf by microwave were as following, liquid-material rate was 30:1, microwave power was 600 W, extraction time was 13 min, and the pressure was 1.4 MPa. Under above conditions, the extracting yield of flavonoids was 1.46%. Comparing with other traditional method, microwave extraction technology has higher productivity and shorter extraction time.2.The primary purification product of flavonoids was extracted form the concentrated solution by macroporpou resin technology. Minewhile, a crude crystal-likely black precipitate was also obtained, precipitating on the vessel wall during concentrating. Two kinds products were analysesed by thin layer chromatography, and the result showed that the primary purification sample of flavonoids contained 8 components and the crude crystal-likely black precipitate sample included 5 components.3. Colorimetry analysis showed that the total flavonoids contents of the crude crystal black precipitate and the primary purification flavonoids samples were 57.1% and 18.5% respectively. Under the optimized hydrolysese conditions of temperature at 80-90℃in 1.4mol/L HCl of methanol solution for 4h, we got the best result. HPLC detection demonstrated that 32 components were separated form the crude crystal sample and 7 of them have been confirmed; 22 components were separated form the primary purification sample and 5 of them were identified; 28 components were separated from the hydrolysate of the crude crystal-likely black precipitate sample and 7 of them were identified; 25 components were separated from the hydrolysate of the primary purification sample and 7 of them were identified. Accoding to the indentification result, reed leaf contained rutin, scutellarin, hesperidin, luteolin, quercetin, apigenin, kaempferol, isorhamnetin or hesperetin, isoliquiritigenin, baicalein, and many other unknown flavonoids, and the content of apigenin was the highest ingredient in those components.4. The in vitro antioxidant test had been demonstrated all the five isolates obtained from the primary purification sample by thin layer chromatography had some antioxidatn capacity and there are dose-effect relationships. The order of ability of DPPH radical scavenging among the five components is 3#>2#>4#>1#>5#;The order of ability of ABTS radical scavenging among five components is 3#>2#>1#>4#>5#;under phosphorus molybdenum complex determining system, the order of total ability in radical scavenging among five components is 2#>1#>3#>4#>5#。...