Separation And Analysis Of The Antioxidant Activity Of Extracts Of Eichhornia Crassipes

Using Eichhornia crassipes as raw material,the effective components of antioxidant activities were studied,and the extraction,isolation,purification,and the structure of the antioxidant activity of Eichhornia crassipes were researched.Qualitative tests indicated that Eichhornia crassipes contain phenol compound, ellagitannins,flavonoids,organic acids,reducing sugars and volatile essenee,but don't contain saponins,coumarin compounds,terpene lactone,anthraquinone and alkaloid.The antioxidant activity of Eichhornia crassipes were primary proved.Eichhornia crassipes is one of the basic material which can improve antioxidant ability in organism.DPPH assay,α-deoxyribose oxidation assay(hydroxyl radical-scavenging) and FRAP assay(Ferric Reducing Antioxidant Power) were used to determine the antioxidant activity from the extracting material in Eichhornia crassipes and other 8 plants.The results showed that Eichhornia crassipes and Indus deciduous leaves had high antioxidant activities in all three antioxidant activity assays,while straw and stem showed low antioxidant activities. There were positive correlations between the antioxitant activity assays,and the total flavonoids content.The value of DPPH·radical scavenging was shown to provide higher positive association with FRAP value(R~2=0.8301) and the total flavonoids content(R~2=0.8216) respectively.Therefor,DPPH assay was the better indicators of extracting antioxidant activity from Eichhornia crassipes.Orthogonal experiments of extracting antioxidant activity from Eichhornia crassipes were separately carried out using of hot water soaking,ultrasound and microwave extraction methods.After that,the optimum conditions of extracting antioxidant activity from Eichhornia crassipes were determined through single-factor experiments.The optimum conditions were(leaf) feed ratio-1:10,ethanol concentration-80%,ultrasonic time-20min, ultrasonic power-120W,(stem) feed ratio-1:8,ethanol concentration-70%,ultrasonic time-30min,ultrasonic power-105W.One compound was purified by thin layer chromatography and silica gel column chromatography from Eichhornia crassipes extractions,which was identificated with UV-VIS, IR,MS and NMR methods.The results show that the compound maybe 6-acetoxy-4, 6-dimethyl-2,4-cyclohexadienone or the isomers of cyclic ketene.