| Dihydromyricetin(DMY) have many physiological activities, and its source is broad. Ampelopsis grossedentata possess DMY with high content. Now the research focusing on DMY is about pharmacological aspect. In order to make the best use of DMY, it is very necessary to study on extraction purity and application character of DMY. The data showed that the results of DMY purity research was focus on chromatogram separation method for the moment. But the investment of chromatogram separation method required high and isn't suitable to substance which has high content. So we studied on the DMY crystal purification method which is facile to industrialization produced from Ampelopsis grossedentata dry bud leaf. We also researched its antioxidant mechanism, application conditions, stability and molecular modification by the numbers. 1. Firstly, the chemical structure of DMY in Ampelopsis grossedentata dry bud leaf was identified. It was named 3,5,7,3',4',5'-6 hydroxy dihydrogen flavonol. At the base of that, the operation condition of HPLC method to determine DMY are immobile phase was Symmetry 300TM C18 3.5 ×150mm; mobile phase is acetonitrile: water:acetic acid 1:9:0.1, pH-value is 3.5; temparature of column is 25℃, velocity of flow is 1.0mol/mL; wavelength of detection is 288nm; injection volume is 10μL. It shows good linearity when the concentration of sample is 10μg/mL～100μg/mL. Through the analysis of LC/MS and quanta chemistry study, it was concluded that there was the coexistent substance with DMY in Ampelopsis grossedentata bud dry leaf. 2. There are 20.27% DMY, 30.22% flavonoid, 12.61% tannin, 8.69% protein, 9.10% dissoluble saccharide and 6.52% total ash in Ampelopsis grossedentata dry bud leaf. There are over 17 kinds of amino acids in it. Using water-heat method to extract DMY in Ampelopsis grossedentata dry leaf, the proper condition : proportion of material and water being 1:20, extracting temperature being 100℃, exstracting time being 30min. Under the condition the distilling ratio of DMY is 22.00±0.99%; The purity of it is 51.60±1.21%. 3. The solubility of DMY in water changed large with the changes of temperature, 1.5900g/100g water at 100℃and 0.0691g/100g water at 25℃respectively. The solubility of DMY in water, ethanol, methanol, propanol, 2-propanol, ethylene glycol, propanediol, acetone, ethyl acetate, acetic acid and n-hexane are high. The solubility of DMY in ethanol solvents change little with temperature but large with solvent concentration. 4. Water repetition crystallization method with the same solute concentration each was used, the better proportion of material to solvent is 15:1000. After five times repetition crystallization, the productivity of DMY crystal was 10.83±0.36%. Grads concentration repetition crystalization method can improve crystal productivity to 15%, the purity being above 95%. The state of product is yellow white acicular crystal and insipidity. Organic solvent repetition crystallization method showed that 60% ethanol was the suitable solvent system. After 5 times repetition crystallization, the purity of product can be up to 98%, and the crystal state was yellow club-shaped, length of which is above 3mm. The productivity of this method is 30.01±1.26%, which is 2 times high than water repetition crystal method. So this method has good exploitation foreground. The crystal producted by water repetition crystal method and 60% ethanol heating extraction repetition crystal method respectively both had higher crystal degree but the crystal configuration are different. 5. DMY has good stability. It will not decompose until heating to 245℃.Under the condition of 238℃, DMY will not take place self-oxidation. But it would be unstable in water with the increasing of temperature and heating time, even be oxidated. So it is suitable that the boiling state should not be contained exceed 30min in the course of extracting and processing. The pH-value is the important factor effecting DMY stability. DMY will be unstable in the alkaline condition(pH >8.0), and will decomp...
|
PDF Full Text Request