Extraction,Purification,Antioxidant And Antimicrobial Activities Of Total Flavonoids From Cyclocarya Paliurus (Batal) Iljinskaja Leaves

Cyclocarya Paliurus(Batal.) Iljinskaja, a kind of Chinese native plant, belongs to the genus Cyclocarya Iljinskaja(Juglangdaceae), the leaves of Cyclocarya Paliurus have been used as sweet tea for a long time. Among these compounds from the leaves of Cyclocarya Paliurus, the flavonoids acting as unique characteristics and have been atracted much attention, which have many biological activities. In this paper, the extraction, purification and structures were identified, the antioxidant and the antimicrobial activities of total flavonoids in the leaves of Cyclocarya Paliurus were detected. The results as follows:(1) On the basis of simple factor experiment, Box-Behnken response surface methodology was employed for detecting the optimum extraction process by the indexes of the contents of total flavonoids from Cyclocarya Paliurus leaves. Total flavonoids of optimum extraction conditions were as follows: ultrasonic power 162 W, 48% of the ethanol concentration, liquid-material ratio of 34 ml/g, ultrasonic time 41 min, under these conditions, the yield of total flavonoids was 8.427 %.(2) Four kinds of macroporous resin and polyamide resin were screened, the best resin is HPD-600. Meanwhile, the static and dynamic adsorption tests were determined to obtain the optimum analytical adsorption conditions. The results showed that the optimum conditions were: the sample concentration was 1.0 mg/m L, the sample flow rate was 2 BV/h, ethanol concentration was 70%. Under this condition, the purity of flavonoids was increased to 69.76% after three times purification. Using HPLC method, the purified total flavonoids preliminary structure, qualitative and quantitative analysis were identified. It was found that the flavonoids in the leaves of Cyclocarya Paliurus may contain the following substances: isoquercetin, quercetin, kaempferol, and the contents of which were 0.993%, 0.249%, 0.168%, respectively.(3) Four indicators as reducing capacity, DPPH radical scavenging capacity, O2-·scavenging effect, the ABTS+ radical scavenging activity were applied to investigate the antioxidant activities of the crud and purified flavonoidsby in vitro assays. The results showed that the antioxidant activities of purified flavonoids were better than those of the crud, and both of which with a dose-dependent manner. The O2-·radical scavenging activity of Cyclocarya Paliurus total flavonoids was higher than that of Vc besides at the concentration of 50-150 μg/ml, while the antioxidant activity of the Cyclocarya Paliurus was lower than those of the Vc.(4) Filter paper method for antibacterial activity of flavonoids study showed that the flavonoids had inhibitory activities against Staphylococcus aureus, Escherichia coli, Salmonella, antimicrobial strength were: Staphylococcus aureus> Salmonella> E. coli.