Polygonum Orientale In The Separation And Analysis Of Flavonoids And Antioxidant Activity

The extraction,purification and determination of total flavones in Fructus Polygoni Orientalis were studied.At the same time,the free radical scavenging activity of the total flavones and taxifolin were also investigated primarily.(1)Extraction of total flavones.Ultrasonic-assisted extraction and microwave-assisted extraction were studied systematically.And the best extraction process,microwave-assisted extraction,was obtained by the orthogonal test,with the yield of 3.41%.(2)Purification of the total flavones.Five kinds of macroporous resin were studied systematically.Total flavones in Fructus Polygoni Orientalis was absorbed and desorped well by S-8 macroporous resin. 1.50mg/mL extraction solution was added into the column with the rate of 1BV/h up to resin being saturated absolutely.Total flavone was eluted by 60%(v/v)ethanol with the rate of 1BV/h.The purity of total flavone was 83.26%.(3)Separation of taxifolin.Three methods,the lead salt precipitation, silica gelcolumn chromatographic and preparative high performance liquid chromatography,were used to separate taxifolin in Fructus Polygoni Orientalis.And the best separation condition was obtained. Preparative high performance liquid chromatography was most effective in three methods and the purity oftaxifolin was 96.26%.(4)Determination of the total flavones and taxifolin.The total flavones in Fructus Polygoni Orientalis were determined by spectrophotometry with rutin as standard control.The equation of linear regression was A=3.81×10^-4+6.66×C(r=0.99935),with a good linear relationship in the range of 8～64μg/mL.High performance liquid chromatography(HPLC)was developed to determine taxifolin,and the optimal conditions of separation and detection were achieved on a Lichrospher C₁₈column(150 mm×4.6 mm,5μm)with the mobile phase of CH₃OH-H₂O-CH₃COOH,detected at 290 nm.The flow rate was 0.8 mL/min.The equation of linear regression was Y=1.54×10³+1.40×10⁴×C (r=0.99995),with a good linear relationship in the range of 25～150μg/mL.(5)The antioxidation activities of taxifolin and flavonoid extract from Fructus Polygoni Orientalis,the DPPH radical scavenging effect, were investigated.Fructus Polygoni Orientalis extracts showed good activities,and the antioxidation ability of extracts with different solvents was in the order of methanol extract＞ethanol extract＞distilled water extract＞ethyl acetate extract＞chloroform extract.And taxifolin had better antioxidation activity than rutin,which showed taxifolin was excellent free radical scavenger.