Research On Separation And Purification Of Antioxidants From Eichhornia Crassipes And Influence On The Adsorption Of Heavy Methals

Eichhornia crassipes collected from Pearl Spring of Nanjing were used as raw material. The research in this article were about antioxidative ability, separation and purification, structure of antioxidants extracted from eichhornia crassipes, adsorption of heavy metals and effect on antioxidative ability of eichhornia crassipes.The total flavonoids, content of polyphenols, scavenging of DPPH radical and reducing power had good characterizations of antioxidative ability of natural antioxidants. There was a good concordance between the total flavonoids and antioxidative ability of non-fruit plants, the content of polyphenols was correlative well with antioxidative ability of fruits and vegetables.The optimum conditions of separation and purification of antioxidants extracted from eichhornia crassipe stems with DPH-400 macroporous resins were:sample flow velocity of 0.8mL/min, pH=4; washing with 80% ethanol at the flow velocity of 0.8mL/min, pH=6,5BV of eluting solvent. The optimum conditions of separation and purification of antioxidants extracted from eichhornia crassipe leaves with AB-8 macroporous resins were:sample flow velocity of 0.8mL/min, pH=2; washing with 80% ethanol at the flow velocity of 0.8mL/min, pH=5,5BV of eluting solvent. After purification by macroporous resins, the total flavonoids of extract from eichhornia crassipe stems rose from 3.9% to 58.7%, the total flavonoids of extract from eichhornia crassipe leaves rose from 12.3% to 55.6%.Antioxidants separated and purified by macroporous resins and silica gel column chromatography had been characterized by UV-VIS and MS.A preliminary analysis showed that antioxidants from eichhornia crassipe stems and leaves had the same composition and content distribution, and they had strong conjugated structures. Most fractions had good antioxidant ability.Eichhornia crassipes had a good ability to remove Pb in water. Eichhornia crassipe stems' ability of adsorption and anti-poison Pb were higher than eichhornia crassipe leaves'. Pb could be removed from extract of eichhornia crassipes by ultrasonic extraction. Antioxidative ability of antioxidants from eichhornia crassipe leaves was higher than that from eichhornia crassipe stems, but ability of anti-poison Pb of antioxidants from eichhornia crassipe stems was higher than that from eichhornia crassipe leaves.