Patent Application
20120309947
1. Field of the Invention
The present invention relates generally to a ginsenosides extraction technology, and more particularly to a method and system for continuous separation and purification of ginsenosides.
2. Description of Related Art
Ginseng refers to the root of Araliaceae perennial herb: Panax ginseng C. A. Meyer, which was recorded in Shennong's herbal classic as a top-grade drug. Modern pharmacological studies prove that, Ginseng can regulate the central nervous system and immune function, anti-oxidation and anti-inflammation, reduce blood sugar and improve digestion and metabolic functions, etc. Among various effective constituents of Ginseng, ginsenosides including Rb1, Rb2, Rc, Rd, Re, Rg1 and Rh2 are response for its physiological activities, of which Rb1 can lower the blood lipid, anti-oxidation, anti-inflammation and adjust the immune functions, whilst Rg1 is believed to be capable of stimulating central nervous system, resisting fatigue, improving memory and learning functions as well as promoting angiogenesis; and Rh2 is capable of restraining proliferation of cancer cells and tumor.
With regard to common ginsenosides extraction technologies, as shown in U.S. Pat. No. 7,759,101, ginsenosides glycosidase could be used to increase the content of ginsenosides, or in U.S. Pat. No. 7,371,416, a 2-h reaction is made at working pressure of 1.4-1.5 kg/cm2, and temperature of 126-130° C.; however, most of impurities in Ginseng extracts could not be removed to improve its purity. In U.S. Pat. No. 7,884,195, column chromatography is employed to increase the content of ginsenosides, but safety considerations are required due to bulk use of organic solvents.
The main purpose of the present invention is to provide a method and system for continuous separation and purification of ginsenosides, whereby supercritical fluid technology and continuous separation & purification system are used to separate and purify ginsenosides from Ginseng extract liquor by controlling the operating temperature and pressure, without the problems of solvent residues and toxicity.
To this end, the present invention provides a method for continuous separation and purification of ginsenosides, which allows to feed Ginseng extract liquor and supercritical solvent continuously into a separation tank at a preset flow rate, wherein ginseng extract liquor is separated to obtain ginsenosides; then, ginsenosides is fed to a purifying tank for purification; the operating conditions of the separation tank and purifying tank are: pressure of 20-30 MPa and temperature of 40-60° C.
The present invention provides a system for continuous separation and purification of ginsenosides, which comprises a holding tank to accommodate Ginseng extract liquor; a separation tank, connected with the holding tank, equipped with an electric heater and used to separate ginsenosides from Ginseng extract liquor; a supercritical fluid vessel, connected with the separation tank to provide supercritical fluid; a high-pressure metering pump, connected between the supercritical fluid vessel and separation tank; a reactant metering pump, connected between the holding tank and separation tank; a precooler, connected between the supercritical fluid vessel and high-pressure metering pump; two preheaters, connected separately between the high-pressure metering pump, reactant metering pump and separation tank; a purifying tank, connected with the separation tank, equipped with an electric heater and used to purify the ginsenosides; two temperature controllers, connected separately with the electric heater in the separation tank and purifying tank.
The following is a typical preferred embodiment of the present invention, which is described below in conjunction with the accompanying drawings:
According to the method of the present invention for continuous separation and purification of ginsenosides, ginseng extract liquor and supercritical solvent are fed at a preset flow rate into the separation tank 12, so as to separate Ginseng extract liquor in the separation tank 12; then ginsenosides are taken out and fed to the purifying tank 19 for purification. In detail, the supercritical fluid vessel 13 is firstly opened, then high-pressure metering pump 14 and valves are used to control the pressure of the separation tank 12, and the temperature controller 20 is used to control the temperature of the separation tank 12, with the operating conditions: 40-60° C., 20-30 MPa, flow rate of supercritical fluid 1 L/hr, flow rate of ginseng extract liquor 0.3-0.5 L/hr, and concentration of 1-5% ginseng extract liquor; then the reactant metering pump 15 is started to add ginseng extract liquor into the separation tank 12 in a controlled way; so ginseng extract liquor can be separated in the separation tank 12 to form ginsenosides and other constituents (e.g.: polysaccharides). Ginsenosides is separated at top of separation tank 12.
After ginseng extract liquor is separated in the separation tank 12, then ginsenosides is fed to the purifying tank 19 for purification; the samples of purified ginsenosides are collected at top (S2) of the purifying tank 19, and flushed reversely 5 minutes with water to separate highly pure ginsenosides samples and collect them at bottom of the purifying tank (S1).
As listed in Table 1, 9 groups of examples are designed experimentally based on orthogonal array of four factors: separation temperature (40, 50, 60° C.), pressure (20, 25, 30 MPa), Ginseng feed concentration (1.0, 2.5, 5.0%) and Ginseng feed rate (0.3, 0.4, 0.5 L/hr).
In detail, ginsenosides samples R at bottom of the separation tank 12 and ginsenosides samples S2 at top of the purifying tank 19 are collected and analyzed to determine total ginsenosides, and calculate the separation efficiency (Ks=total ginsenosides at top of the purifying tank÷total ginsenosides at bottom of the separation tank); the separated value is subject to variable analysis by linear regression of SPSS statistical software. The statistical analysis result indicates that: the concentration of Ginseng extract liquor (1.0, 2.5, 5.0%) and Ginseng feed rate (0.3, 0.4, 0.5 L/hr) do not affect the separation efficiency of ginsenosides (p>0.05), but the operating pressure and temperature will affect the separation efficiency of ginsenosides (p<0.05).
In addition, the data were analyzed using Response Surface Methodology of SPSS statistical software. The statistical results indicate that, as shown in
According to the method and system of the present invention for continuous separation and purification of ginsenosides, ginseng extract liquor can be separated and purified into ginsenosides by using supercritical fluid technology and continuous separation & purification system; as compared with conventional extraction method, the present invention enables separation and purification of ginsenosides by only controlling the operating temperature and pressure, without the problems of solvent residue and toxicity; moreover, ginsenosides can be easily separated from CO2 solvents while the entire system is operated continuously.
