Extraction, Purification, Separation And Identification Of Flavonoids In The Leaves Of Acer Truncatum

Acer truncatum leaves are rich in many biologically active compounds and good sources of flavonoids. Extraction, purification, separation and identification of flavonoids in Acer truncatum leaves were studied in this thesis for better developing this resource. Two methods were applied to extract flavonoids from the leaves of Acer truncatum, that is, ethanol extraction without ultrasonic wave and ethanol extraction with ultrasonic wave. By orthogonal experiment, their optimum conditions were found. The optimum condition of ethanol extraction without ultrasonic wave is that the raw material was soaked in 50% (v/v) ethanol-water solution 25 times as many as its weight for 1.5 h at 70℃. Under this condition, the raw material was extracted two times. The extraction rate was 94.16% in the first time while it was 1.36% in the second time. The optimum condition of ethanol extraction with ultrasonic wave was that the raw material was soaked in 50% (v/v) ethanol–water solution 15 times as many as its weight for 0.5h at 60℃. Under this condition, the raw material was also extracted two times. In the first time, the extraction rate was 96.26% while it was 3.11% in the second time. Compared to extraction without ultrasonic wave, with ultrasonic wave showed much higher efficiency. The static adsorptive and desorptive capacities of 8 types of macroporous resins with different physical properties for flavonoids in the extract were determined to find a suitable resin for their purification. Then, the dynamic adsorption and desorption of the choosed resin to the flavonoids were studied. The results showed that resin DM130 had good adsorptive and desorptive capacities for the flavonoids. The optimum purification condition was that the slight acidified extract solution (pH4-5) containing 1.2-2.3mg/mL flavonoids poured on the resin at 1-2BV/h was eluted with 70%(v/v) ethanol at a flow rate of 1BV/h. The flavonoids adsorbed on the resin could be completely eluted within 3BV. The purified product contained 46.55% flavonoids. Two column chromatographies were used to separate flavonoids in the purified product and one flavonoid was isolated. It was identified as quercetin 3,5,7,3',4'(OH)5-flavone by analysises of melting point, characteristic qualitative reactions and spectrographic data from UV, 1H-NMR, 13C-NMR, IR, ESI-MS. Extraction of flavonoids from the leaves of Acer truncatum without ultrasonic wave and with ultrasonic wave was compared in this thesis, and their own optimum conditions were obtained. A suitable macroporous resin DM130 was selected to purify flavonoids in the extract, and an appropriate purification condition was established. In addition, methods to separate the flavonoids were investigated and a pure flavonoid was gotten. Up to date, systemic studies and development on flavonoids in the leaves of Acer truncatum are little. So, the results from this study can provide for the future relate research. They also have definite theoretical and practical significance in pharmaceutical and now food resource development.