The Study Of Extraction And Antioxidant Effects Of Flavonoids From The Needles Of Picea Wilsonii Mast

Flavonoids is a class of secondary metabolites of plant with various biological activities, which has important physiological functions and wide uses. The Chinese endemic species-Picea wilsonii Mast., which belongs to Picea, Pinaceae, is rich in flavonoids, but it have not been developed and utilized till now. The needles of Picea wilsonii Mast, is used as test material, and the flavonoids is extracted by ultrasonic extraction and microwave-assisted extraction respectively, the flavonoids extraction conditions are optimized by response surface methodology. Antioxidant activities of the flavonoids from Picea wilsonii Mast, are studied by DPPH·scavenging test, ABTS·scavenging test, and Prussian blue reaction. The main results are as follows:(1) The flavonoids is extracted from the needles of Picea wilsonii Mast, using ultrasonic extraction mehtod, the main factors affecting the flavonoids extraction rate are material-liquid ratio, ethanol volume fraction, ultrasonic time, ultrasonic power and ultrasonic temperature. Under the condition of material liquid ratio of 1:20,the influence sequence is:ultrasonic power> ultrasonic time> ethanol volume fraction> ultrasonic temperature. The optimum flavonoids extraction conditions are:ethanol volume fraction is 50.63%, ultrasonic temperature is 64.88℃, ultrasonic time for 49.46 min, ultrasonic power in 319.63 W. The flavonoids extraction rate is 4.11869%.(2) The flavonoids is extracted by microwave-assisted extraction method, the main factors affecting the flavonoids extraction rate are material-liquid ratio, ethanol volume fraction, standing time, standing temperature, microwave power and microwave time. Except for the material-liquid ratio and standing time, the influence sequence is:ethanol volume fraction> standing temperature> microwave time> microwave power. Setting the material-liquid ratio is 1:15, and standing time is 60 min, the optimum flavonoids extraction conditions are:ethanol volume fraction is 53.64%, standing temperature is 67.75 ℃, microwave power is 315.39W, microwave time is 56.47 s. The flavonoids extraction rate is 3.8578%. The results above indicate that:the ultrasonic extraction is better than microwave-assisted extraction for the flavonoids extraction from the needles of Picea wilsonii Mast..(3) The scavenging effect of flavonoids on DPPH·reached 90.21%. Its trolox equivalent of ABTS·scavenging is 29633.3 μmol/g. The reducing ability of the flavonoids of Picea wilsonii Mast. is determined by Prussian blue method, the results show that the flavonoids has strong reducing ability, which is better than that of the same concentration of rutin, but not as good as Vc and quercetin. The above results indicate that:the flavonoids in the needles of Picea wilsonii Mast. has strong antioxidant activity. The acquired results provide a reference for the the development and utilization of the needles resources of Picea wilsonii Mast.