Purification, Composition And Antioxidative And Bacteriostatic Activities Of Flavonoids From Rhamnus Utilis Leaves

Rhamnus utilis,a specie of the genus Rhamnus,is widely distributed in areas below 1500 meters above sea level in China.Its various parts are rich in flavonoids,have antioxidant,bacteriostatic,anti-inflammatory,analgesic,liver protection and other effects.So R.utilis can be used as medicinal materials.But there are few studies on this species.In this experiment,flavonoids from R.utilis leaves were studied.Based on the previous experiments,the optimal conditions for the purification of R.utilis leaves were determined by single factor and response surface experiments.Then the purified flavonoids from R.utilis leaves were analyzed qualitatively and quantitatively by HPLC.Finally,the antioxidant and bacteriostatic properties of flavonoids from R.utilis leaves were compared before and after purification.To provide a theoretical basis for improving the pharmacological action of flavonoids from R.utilis.The specific research contents and results are as follows:1.From HPD-600、NAK-9、AB-8、LX-28、LSA-21、X-5、D101seven different types of macroporous resins,the best separation and purification effect of resin was screened by static adsorption and desorption experiments.By comparing the parameters of different macroporous resins,AB-8 is a suitable macroporous resin.Then,the single factor experiment of purification of flavonoids from R.utilis was p H of sample solution、flow velocity of upper liquid、elution rate and elution concentration.On this basis,the response surface experiment is designed.According to the results of software analysis and practical operability,the purification conditions of flavonoids were as follows: the flow rate of the sample solution p H 3.5 、 the sample solution was 1m L/min、the elution rate was 2.5 m L/min、the concentration of the eluent was 95%,and the recovery rate of the flavonoids from R.utilis leaves reached 65.98% under this condition.2.According to the retention time of flavonoids,rutin andkaempferol in R.utilis leaves were determined by HPLC.In the methodology study,the recovery rate was between 96% and 98%,the RSD of repeatability,stability and precision less than 3.0%.There is a linear relationship between peak area and concentration of rutin and kaempferol in the range 180-900 and 3-20 ug/m L,respectively.Therefore,the content of rutin was 0.698 ug/ug,and the content of kaempferol was0.016 ug/ug in the flavonoids from R.utilis leaves.3.Through FRAP,ABTS,hydroxyl radical colorimetry and DPPH method,the antioxidant properties of unpurified and purified of flavonoids from R.utilis leaves were compared.It is concluded that the antioxidant properties of the flavonoids from R.utilis leaves increased with the increase of concentration before and after purification.At the same concentration,the antioxidant properties of flavonoids from purified R.utilis were stronger than those before purification.The bacteriostasis of the flavonoids from R.utilis leaves on Staphylococcus aureus,Salmonella,Escherichia coli and Bacillus subtilis before and after purification was investigated by bacteriostasis circle method.The results showed that the higher concentration of flavonoid solution,the more obvious the bacteriostatic effect was.And the bacteriostatic properties of flavonoids from purified R.utilis leaves were stronger than those of unpurified,under the same concentration conditions,the inhibitory effect from strong to weak followed by Staphylococcus aureus > Bacillus subtilis >Escherichia coli > Salmonella.