The Extraction And Separation Of Flavonoids In Mikania Micrantha As Well As The Study Of Their Biological Activities

Mikania (Mikania micrantha) is a perennial vine of Asteraceae, also known as flowers Zeeland. As dangerous invasive species from abroad, it is called "plant killer" because of its destroying ecological balance. The extraction of nutrients and bioactive substances from Mikania micrantha H.B.K has become urgently needed to its control and utilization. Plants flavonoids were shown to have functions, such as antioxidation, baeteriostasis, inhibiting cancer cell proliferation, reducing blood fat and so on. Previous study has shown that Mikania micrantha contains many kinds of bioactive substances including flavonoids. Up to now, there has not found systematic and detailed studies on its extraction, separation, purification and bioactivity, which bring negative effects of utilities and exploitation of active components in Mikania micrantha. In this paper, the best extraction, preliminary purification and different bioactivity were researched, which can enhance the application of Mikania micrantha and provide a useful guideline for investigation of new drugs. The main investigations and experimental results in this paper were listed as follows, respectively:To develop an ultrasonic extracting method for total falconoids in different organs leaves and stems of Mikania micrantha, we employed AI(NO3)3—NaNO2-NaOH method to determinate falconoids content and optimized the extraction process by orthogonal design. The results indicated that methods above were fit for the extraction and determination of falconoids; The difference in falconoids content and species result of disparate craft for respective organs; For leaves, ethanol concentration, fate of material to liquid, ultrasonic power and time were50%,1:30,50W,50min; respectively, for stems, the optimum extraction conditions were60%of ethanol concentration, the fate of material to liquid being1:30,60W of ultrasonic power and40minutes of ultrasonic time. The extracting rate of leaves with10.62%is much more than that of stems with6.20%.The flavonoids extract of Mikania micrantha leaves prepared by optimal crafts were identified by the color reaction, UV and IR. Then, the above flavonoids extract was partitioned between normal solvent petroleum ether, CH3CH2OOCH2CH3, n-butyl alcohol and the odd extract to get four fractions. The results indicated that the flavonoids extract of Mikania micrantha leaves consisted mainly of flavone、flavonol. The flavonoids content ratio of the four fractions was about0.1:1:2.5:2.Studyed the activities of the above main three partition fractions from Mikania micrantha leaves in many ways. First, the bacillus (Staphylococcus aureus, Escherichia coli, Salmonella and Shigella) were selected to in bacteriostasis experiments in vitro. And the effect of inhibiting the microorgansims was determined by the inhibition zone diameter, MIC test. Second, assayed the activities of the main three partition fractions from Mikania micrantha leaves by using DPPH radical scavenging, hydroxide radical scavenging and superoxide radical scavenging. Last, the inhibition activity of the main three partition fractions on the proliferation of human lung cancer A549cells were investigated using MTT method. The results showed that the flavonoids partition fractions have significant and various kinds of activities, which can be used as a source of potential bacteriostatics, antioxidative and tumoricidal agent. Meanwhile, the results indicated that there exits difference between the main three partition fractions in respective activity experiments and the bioactivity of CH3CH2OOCH2CH3fraction was especially significant.To explore the effect of flavonoids extract from Mikania micrantha leaves on blood lipid and health of mice with hyperlipidemia, a high fat diet was used to create a hyperlipidemic model. Results showed that flavonoids extract of Mikania micrantha leaves could reduce serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) levels and increased high-density lipoprotein cholesterol (HDL-C) level. In addition, the cholesterol-lowering effect on TG and HDL-C were better. Meanwhile, the flavonoids extract could also protect the liver of mice to some extent.