Studies On The Extraction And Activity Of Baicalein And Preparation Of Baicalein Liposome

Baicalein is one of the effective ingredients of Chinese herbs Scutellaria baicalensis Georgi, it can antibiosis, antiviral, anticancer and other pharmacological actions. At the present time, extraction and separation of baicalein is used to immersion method, which is time-consuming and low productive rate, and the studies are focus on its extraction and separation in our country, but extraction processing has never been reported yet. Consequently, it is necessary to search the effect factors of baicalein for extraction and separation.Free radicals are the general intermediates of biochemical reactions in organisms. When free radicals are produced excessively or removed extreme slowly, they will attack a lot of diseases. Therefore, screening natural antioxidant became focus at home and abroad. Because flavonoid has antioxidation, and baicalein is one of the flavonoids. Consequently, the scavenging effects of the baicalein were studied.Liposome has the character of covering fat-soluble drug and water -soluble drug. Fat-soluble drug present different characters and its solubi -lity of drug is increasing, when it was covered. Otherwise, liposome has targeting and releasing actions, and it can increase therapeutic effectiven -ess and reduce sideeffect. Because baicalein has low solubility in water and is oxidized easily. Preparation method and in vitro pharmacodynami -cs of baicalein liposome were researched to improve its stability and biological utilization ratio.This dissertation consists of five chapters focusing on the study of the extraction, separation, chemical characters and biological activities baicalein, which is one of the effective ingredients of Chinese herb Scutellaria baicalensis Georgi, and the preparation technique for baicalein liposome was researched. The concrete work mainly has following few aspects:1. Build up measurement the method of the contents of baicalein isHPLC method. To take the content of baicalein and extraction ratio of baicalein as an index, the optimal enzymolysis procedure for improving the yield of baicalein from Scutellaria baicalensis Georgi were investigated .In order to optimize the enzymolysis procedure we adopted orthogonal experiment design (3 factors and 3 levels) to determine the enzymolysis conditions. The optimal enzymolysis conditions are as follows: enzymolysis the temperature is worth for 40°C, pH 6.0, time is 12h. The content of baicalein of the extraction solution is the highest under these conditions. At the same time, we have studied the advantages and disadvantages of three factors of extraction processing technology of Ultrasonic Wave Extraction of baicalein to make sure the optimal extraction conditions. The optimal extraction conditions are extracting times 2, extracting time 30 minutes and 95% ethanol volume 150ml by using orthogonal experiment design (3 factors and 3 levels). Under the conditions, an extraction ratio of baicalein as high as 76.5mg/g was obtained. In comparison with the ethanol extraction technology, the results showed that ultrasonic wave extraction was more efficient than the normal method solvent extraction and shortened the extracting time largely.2. The effects of light, temperature, pH, vitamin C and sodium sulfite on the stability of baicalein have been studied by using UV-Vis spectrum. The results shown that the absorbency intensity of baicalein at 272 nm have weaken in 6hr. in the condition of keeping solution of baicalein at the room-temperature, when keep the high temperature or in the dark, the absorbency intensity of acid baicalein solution can keep stabilization in 6hr. but the absorbency intensity of baicalein solution have still weaken in the condition of pH 10;the absorbency intensity of baicalein solution can maintain stabilization, when add a few of vitamin C or sodium sulfite to the solution, The paper suggests that baicalein is very unstable to light and pH especially under the condition of alkali (pH=9. 0), and vitamin C and sodium sulfite can improve the stability ofbaicalein solution.3. The scavenging effects in vitro of the baicalein on l,l-diphenyl-2-picrylhydrazyl free radical (DPPH), the scavenging effects of the baicalein on superoxide radical (O2"-) and the protective effect of baicalein on the deoxyribose damage in vitro caused by hydroxyl radical (HO) were studied by using UV-Vis spectrum. The results shown that baicalein could be well used in scavenging superoxide radical, and the scavenging effects of the baicalein on l,l-diphenyl-2-picrylhydrazyl free radical had a quantitative relationship, moreover the larger the concentration, the stronger the scavenging effects. Further research discovered that pH had a great effect on the DPPH free radical scavenging rate, the scavenging rate of the baicalein is the maximum when pH is about 3.0. Experiments also revealed that baicalein can act as effective natural antioxidants and free radical scavengers because of its high antioxidant activity.4. Using the method of enzyme activity, we have studied the inhibition of Porcine Pancreatic elastase in vitro by baicalein .The results indicate that baicalein is very strong in the capacity of the inhibition of Porcine Pancreatic elastase, the inhibition rate is 92.98%.5. Make use of the UV-Vis spectrum method, to take the drug loading and entrapment efficiency of baicalein liposome as an index, the optimal operation conditions of preparing baicalein liposome were studied by two different preparing methods: reverse-phase evaporation and thin-film ultrasonic dispersion. Moreover the liposome and free baicalein were separated by centrifugation, and the diameter and morphology of baicalein liposome were studied by distribution of size and transmission electron microscope. The results shown that the mean diameter, drug loading and entrapment efficiency of baicalein liposome by reverse-phase evaporation were 179nm, 92.57% and 23.24%;275nm , 60.02% and 7.70% by thin-film ultrasonic dispersion, so the former is better than the latter. Further research discovered that the drug release invitro was found to be matched up with Higuchi equation, in a buffer of pH7.4 which was prepared from NaH2PO4-Na2HPO4 system. Under the release condition, cumulative drug release rate is 57.13 %by the end of 15 hour. Experiments indicate that Reverse-phase evaporation method of baicalein liposome preparation is easy to operate, repeatable and efficient, and liposome is high encapsulation efficiency, the content of baicalein in liposome is also high, and there are no distinct changes in shape and size distribution of liposome. The release of baicalein liposome in vitro is practicable and successful.