Study On The Purification Of Salidroside And P-tyrosol In The Extract Of Rhodiola Sachalinensis By Ultrafiltration

Rhodiola sachalinensis is a perennial herb or the Asian bush plant of Rhodiola L. of Crassulaceae. Its, the stem, the flower, the seed all may be used as medicine, which have many kinds of pharmacology activities such as the anti-oxygen deficit, anti-fatigue, anti-virus, anti-tumor, anti-radiation, anti-senile, the immunity enhancement and so on. And it is called, continuing the ginseng and Ciwujia, the new generation of environment medicine to adapt the original. At present, it is obtaining the extensive research and application. The chemical composition in its original plant raw material for medicine mainly includes the glucoside class, the flavanone class, the coumarin, the tanning substance and so on, in which salidroside and p-tyrosol, while whose content is actually low, are its main active constituents. Therefore, it is necessary to carry on the separation and the depuration to its main effective components in order to overcome the shortcomings of badly product quality and the dosage in a big way in taking. The literature reported the separation and depuration methods include solvent extracting and column chromatography. The column chromatography may obtain salidroside of high-purity. However, with the seriously loss of effective component and the very low recovery rate, this method is only suited to apply to trace standard preparation. The method of solvent extracting has the shortcomings of big solvent consumption, the complex craft steps and the high cost, moreover, also brings certain pressure to the environment.The technology of ultrafiltration is an item of membrane separation technology which started to develop in 70s of the 20th century. It has the merits of energy conservation, highly effective, environmental protection, operation simple and the higher recovery rate of effective components. At present, this technology is rapidly developed, and has been widely applied in domains such as food, medicine, industrial waste processing, ultra pure water preparation and biological technology industry. Therefore, studying its application in the purification of salidroside and p-tyrosol has a vital practical significance.The author applied the ultrafiltration technology to the separation and purification of the extract of Rhodiola sachalinensis original plant raw material for the first time in this experiment. The material of the hollow fiber ultrafiltration membrane used, the relative interception molecular mass, and the suitable craft parameter have been researched contrastively. The contents of solid, non-water impurity ingredient, main effective components salidroside and p-tyrosol (of salidroside ) in the leaching solution, microfiltrate and the ultrafiltrate were determined by the methods of weighing, absorption and ultraviolet spectrophotometry separately in order to appraise the separation and depuration effects of the ultrfiltration membrane. Finally, overall evaluation of each kind of factor, we chose the best technological conditions of ultrafiltering the Rhodiola sachalinensis leaching solution: membrane material: PS; relative interception molecular mass: 10000; feed temperature: 40℃; service pressure: 0.10 MPa; feed concentration: 0.10 g/ml; pH value: 7.0; Feeding speed: 530 ml/min. Under the best technological conditions, the ultrafiltration experiment was carried on again and the treatment effects were inspected. The results indicated that, the solid content reduced to 0.1028g/10ml from 0.3769g/10ml, the content of main effective components salidroside and p-tyrosol enhanced to 15.58% (wt.) from 4.20% in the solution by ultrafiltration. The recovery rate of the ultrafiltration process was 98.00%. The recovery rate of the total process reached 94.37%.The average permeation velocity was 233.17ml/10min in 150min of ultrafiltration. And the processing effect has achieved the anticipated standard.In the use process of the ultrafiltration membrane, a main question is that the membrane fouling may lead to the sharp decline of the membrane flux. Cleaning is an effective method to slow down the membrane fouling. For the hollow fiber ultrafiltration membrane fouled by the leaching solution of Rhodiola sachalinensis, according to the fouling mechanism, the appropriate chemical cleaning agents and cleaning modes were experimented and chose, and the influences of lotion type, concentration, temperature, the cleaning time and cleaning order on the membrane flux restoration ratio were also researched in this article. The results indicated that the cleaning order had a great influence. It was preferable to clean with first base after acid, and then surfactants. The best combination of cleaning agents and cleaning methods were: high velocity rinse water (room temperature, 10 min)→water- gas mixture cleaning (room temperature, 10min)→NaOH (0.75%, 40℃, 40min)→NaOH (0.25%) +Na5P3O10 (0.5%, 40℃, 40min)→HCl (1.0%, 35℃, 30min)→SDS (0.5%, 35℃, 30 min)→rinse water (room temperature, 20 min). Under the optimum experimental conditions for cleansing, the restoration ratio of the membrane flux reached 90.6%. The result was desirable, which may provide a reference for studying cleaning methods of ultrafiltration membrane fouled by other Chinese medicine extracts.