Study On Preparation Of Curcumin From Turmeric By Selective Extraction

Curcumin is one of the most important active substances in Curcuma longa L. (Turmeric), which has antibacterial, inhibition of hepatitis, repair damage to the liver cells, and improve liver parenchyma damage effects, widely used in food and drug. Usually, curcumin was obtained through chromatographic separation methods, but the methods were time consuming, low yields and complex technology.In order to overcome the shortcomings of traditional methods, through exploration, a simple and efficient method for separation curcumin from Curcuma longa L. by selective extraction was studied in the paper. The specific contents were as follows:1. Establishment of Inspection methods (High Performance Liquid chromatography, HPLC). By changing of composition and ratio of the mobile phase (methanol-water, acetonitrile- water, acetonitrile- 1% acetic acid and water), the column temperature (25℃,30℃,35℃,40℃), the flow rates (0.20 mL/min,0.40 mL/min,0.60 mL/min,0.80 mL/min,1 mL/min) and the detection wavelength, an effective method for separation and determination of curcumin, demethoxycurcumin and bisdemethoxy-curcumin by HPLC were achieved.The results indicated that the optimal chromatographic condition was as follows: Chromato-graphic columns:Acclaim TM 120 C18 120A (250 mm×4. 6 mm,5 μm), the mobile phase for acetonitrile:1% acetate =44:56 (V/V),column temperature 30℃, flow rate 1.0 mL/min, and detection wavelength of 254nm.2. Extraction of curcuminoids. By comparing the different solid-liquid ratio (1:5,1:10,1:15), different concentrations of ethanol (75%,85%,95%) and at different time (30min,45min,60min), the optimal conditions for extraction of curcuminoids was obtained. Experimental results show that the solid-liquid ratio 1:10,95% ethanol and ultrasonic 45min for the best conditions for extraction curcuminoids from Curcuma longa L..3. Isolated curcumin from the Turmeric extract. Curcumin was isolated from curcuminoids by selective separation method with polyethylene glycol (PEG) as stationary phases. In solution system,because of the capacity of curcuminoids combining with polyethylene glycol was different, curcumin and other curcuminoids compounds occurs a clear hierarchy in the liquid phase, so curcumin could be selectively isolated form the mixture. Specific process was as follows:Turmeric extract was dissolved in anhydrous ethanol, then adding PEG solution, using petroleum ether and n-hexane as extractant for direct extraction of curcumin, the separation condition were tracked and detected by thin-layer chromatography, and determination of qualitative and quantitative by using HPLC, through examining the distribution of curcumin in two phases, and comparative analysis of the data, achieved the optimum separation conditions. Through research, the major factors affecting the extraction efficiency was: extractant ratio, the ratio of alcohol-water, molecular weight PEG, PEG concentration, temperature and frequency, and so on. After the experiment, optimum conditions were:the extraction solvent petroleum ether:=97:3 hexane (v/v), alcohol and water than 36:64 (V/V),1% PEG6000, PEG concentrations, temperature 30℃, extract 3 times. Under these conditions, curcumin extraction rate was 52%, and 91.7% purity.Experimental results show that, by joining the polymer PEG selective adsorption of impurities in the extract, the purpose of purification of the target product. Therefore, selective separation of curcumin from turmeric peg extraction systems was also possible, the process was easy to operate, high efficiency, simple technology, it provided an important reference for direct separation of three main effective components in turmeric, and for further research, development and application of curcumin derivatives provide the scientific basis.