Purification Of Flavonoids From Peony By Membrane Method And Its Whitening Activity

Peony is rich in,which have the function of antioxidant,whitening and cardiovascular protection.In this paper,the related technological parameters in the process of purification of crude extract of peony flavonoids by multi-stage membrane filtration were systematically studied,the filtration and purification process through experiments were optimized,and studies its the flavonoids of Peony’s whitening activity were studied.The main contents of this study include the following aspects:(1)Ultrafiltration membranes with different pore sizes are prepared with different ratios of membrane-forming liquids,which are used for pre-filtration of crude extract of peony flavonoids..And the results showed that the PES ultrafiltration membrane with the casting solution ratio of PES:DMAc:PVP=24:75:1 had a well effect on the removal of impurities in the crude extract of peony flavonoids,The purity of flavonoids is up to 15.6%.The membrane after the flux drops can be cleaned by simply washing and soaking with pure water,and the flux recovery rate can reach more than 90%.(2)two-stage nanofiltration membranes with different pore diameters are used for grading filtration-concentrating the extract of peony flavonoids to achieve the purification of peony flavonoids.45-50℃ is the best temperature range of material liquid in the first-stage nanofiltration membrane process,1.2-1.4 MPa is the best filtration pressure range,10-14 cm/s is the best range of membrane surface flow rate,which can make the filtration flux larger and the purification effect better.The purity of peony flavonoids reach 52%-56%after filtration.The flux of nanofiltration membrane running for a long time can be reduced by immersion cleaning with 70%ethanol aqueous solution,and the flux recovery rate can reach 90.2%.The best temperature range of material liquid in the process of secondary nanofiltration membrane is 46-54℃,the best filtration pressure range is 1.4-1.6 MPa,the best membrane surface flow rate is in the range of 13-18 cm/s,which can ensure a large flux,and the retention rate of flavonoids can reach 99%.After the flux of nanofiltration membrane is reduced,70%ethanol aqueous solution can also be used for immersion cleaning,and the flux recovery rate can reach more than 93%.Finally,the purity of the flavone was increased from 15.6%to 79%after the two-stage nanofiltration membrane filtration and purification.(3)The whitening activity of peony flavonoids was characterized by measuring the inhibition rate of peony flavonoids to tyrosinase.The results show that the IC50 of tyrosinase monophenolase is 4.8 mg/mL and the IC50 of tyrosinase diphenolase is 13.8 mg/mL,whose were similar to that of phenylethyl resorcinol.Therefore it can be used as a tyrosinase inhibitor and a potential whitening cosmetic additive,which would have a good market prospect.