Study On Isolation,Purification And Identification Of Flavonoids In The Petal Of Paeonia Ostti Cv. ’Phoenix White’

Paeonia ostti cv.‘Phoenix White’,a genus of peony,belongs to the Chinese peony family.The seed and root bark are used more rapidly than other petal and other parts.It has a very large yield of petal,about 2000 Kg fresh（about 250 Kg in dried）per acre.Four parts of it were used as raw material to compare the content of total flavonoids,total polyphenols,and antioxidant properties.Then,extraction,purification,isolation and identification of flavonoids in the petal was studied.This paper provided theoretical basis of Paeonia ostti cv.‘Phoenix White’.Content of total polyphenols,flavonoids and antioxidant activities in different parts of Paeonia ostti cv.‘Phoenix White’were compared.There was a significant difference（P<0.01）in the content of total polyphenols among parts.A significant difference（P<0.01）existed in the content of flavonoids.VE,VC,PG and BHT were chosen as control.Antioxidant activities in ethanol extract of petal were better than other parts at the concentration of 1.0 mg/m L.Traditional ethanol extraction method（TEE）,ultrasonic assisted extraction method（UAE）and microwave-assisted extraction method（MAE）were used to extract total flavonoids from the petal of Paeonia ostti cv.‘Phoenix White’.The results showed that the optimal solvent for TEE was 80%（v/v）ethanol,temperature of 60℃,solid-to-liquid ratio of 1:60（w/v）,time of 46minutes and extract twice.The best parameters for UAE were power of 300 W,time of 60 min.The optimal parameters for MAE were as follows:power of 500 W,extraction time of 100 s and its yield was（13.77±0.09）mg/g.There was no significant difference（P>0.05）among the yields of three methods but the MAE had the highest efficiency.Polyamide was selected from 7 alternative resin materials as primary filler for separation and purification of flavonoids.At 25℃,the Freundlich model evaluated the isothermal adsorption behavior of polyamide on total flavonoids better and the pseudo-second-order kinetic equation was more suitable to describe adsorption behavior.The process was influenced by surface diffusion and intragranular diffusion.Polyamide column chromatography was used to purify total flavonoids.Parameters of purification were as follow:the loading concentration was 0.75 mg/mL,the loading volume was 1.1 BV,the flow rate was 1 BV/h,eluted in the order of 4 BV of deionized water,6 BV of 20%ethanol,7.5 BV of 40%ethanol,6 BV of 60%ethanol,6.5 BV of 80%ethanol and 5.5 BV of 100%ethanol.Glycosides of dihydrocanein,kaempferol,isorhamnetin,luteolin,and apigenin were found to be main flavonoids in different eluate fractions by liquid chromatography-mass spectrometry method.Two flavonoids glycosides with the purity of 98.02%and 95.90%were isolated by silica gel column chromatography,Dr Flash II medium,low pressure preparative liquid chromatography together with Waters 2545 liquid chromatography from 20%ethanol eluted by polyamide.Kaempferol-3-O-（2’’-O-β-D-glucopyranosyl）-β-D-galactopyranoside and apigenin-7-O-β-D-glucopy-ranosyl-4′-O-α-L-rhamnopyranoside were identified as by mass spectrometry,¹HNMR and ¹³CNMR.These two flavonoids were firstly isolated from the petal of Paeonia ostti cv.‘Phoenix White’.