Extraction of 10-DAB from Taxus Leaves by Supercritical CO2 Extraction Process
Supercritical co2 extraction process
Extraction pressure: 30 MPa
Extraction temperature: 50°C
Separation kettle Ⅰ pressure: 10 MPa
Separation kettle Ⅰ temperature: 60°C
Separation kettle Ⅱ pressure: 6 MPa
Separation kettle Ⅱ temperature: 45°C
Entrainer: 80% ethanol solution
80% ethanol entrainer volume (ml) : 1: 1.5
Extraction time: 90 min
Taxus, also known as yew, also known as yew pine, was born in a mountainous area 100-120m above the sea.
It is recognized as an endangered natural rare plant, and paclitaxel extracted from it is currently one of the most effective anticancer drugs in the world. 10-deacetylbakatine (also known as 10-deacetylbaccatin III, 10-deacetyl baccatin, 10-DABIII) is a taxane diterpene compound that has a tumor-inhibiting effect. Bissery et al.  reported that 10-DAB could be used to synthesize docetaxel with higher anticancer activity than paclitaxel. 10-DAB is mainly present in leaves, and its content is much higher than that of paclitaxel . If paclitaxel is directly extracted from the yew bark, it will not only have limited resources, but also not conducive to the protection of resources. Enzyme-catalyzed semi-synthetic preparation of paclitaxel using 10-DAB as the raw material can greatly simplify the synthesis process, make paclitaxel skeleton modification with fewer steps, simpler operations, and improve the selectivity and productivity of paclitaxel synthesis.
At present, the literature reports that the methods for extracting 10-DAB from various yew plants require a long extraction process. This experiment uses a supercritical CO2 extraction process. The extraction time is short and the process is simple. It is of great significance for the further comprehensive development and industrial production of yew 10-DAB, and then provides conditions for the production of paclitaxel on a larger scale.
6L supercritical CO2 extraction device
HA231-50-06 consists of an extraction kettle, 3 separation kettles and a distillation column.
Taxus, Meizhou, Guangdong;10-DAB (95% purity);
CO2 (purity: 99.9%, Guangdong Shunde Folun Gas Co., Ltd.);
Anhydrous ethanol and methanol (analytical grade, Guangzhou Chemical Reagent Factory);
Acetonitrile (chromatographic grade, Merck); methanol (chromatographic grade, Merck).
Supercritical CO2 Extraction of 10-DAB from Taxus
Extraction process: CO2 cylinder → extraction kettle → separation kettle I → separation kettleⅡ → separation kettleⅢ → CO2 circulation.
Each experiment weighed 150.00g of the prepared medicinal materials each time and put them into the extraction kettle, heated the extraction kettle, separation kettle Ⅰ, separation kettle Ⅱ, Ⅲ, and cooled the refrigerator and storage tank.
When the temperature reaches the requirements of the experiment, open the carbon dioxide gas cylinder, pressurize the extraction kettle and the separation kettle with a high-pressure pump. When the pressure reaches the value required by the experiment, close the carbon dioxide, open the circulation valve, and perform the extraction cycle. Each cycle is 30min. , Discharge from separate kettle Ⅰ, Ⅱ, Ⅲ respectively.
The effects of the amount of entrainer, extraction time, extraction pressure, extraction temperature, and separation conditions on the extraction rate were investigated through a single factor experiment. Orthogonal experiments were designed based on the results of the single factor experiment to screen the optimal extraction process conditions.
Results and analysis
Single factor test of extraction process
Effect of Entrainer Amount on Taxus 10-DAB Extraction Rate
During supercritical CO2 extraction, the entrainer plays an important role in adjusting the polarity of CO2. In this experiment, 80% ethanol was used as the entrainer to investigate the effect of different amounts of ethanol on the extraction rate of 10-DAB. At an extraction pressure of 30 MPa, an extraction temperature of 50 ° C, a pressure of 10 MPa in the separation tank I, a temperature of 60 ° C., and a pressure of 6 MPa in the pressure tank II, and a temperature of 45 ° C., the volumes of ethanol used in the four experiments were 75 ml and 150 ml , 300ml, 450ml. The effect of the amount of entrainer on the extraction rate of the extract was investigated.
When the amount of ethanol is about 300ml, the extraction efficiency of yew 10-DAB is the best. From the perspective of saving solvents, 300ml of 80% ethanol solution is selected as the preferred entrainer.
Effect of Extraction Time on the Extraction Rate of Taxus 10-DAB
The extraction time has a significant effect on the 10-DAB extraction rate. Short time, 10-DAB extraction is incomplete, waste of raw materials; long time, 10-DAB extraction can be completed, but the equipment consumes large energy and is not economical. In this test, the extraction pressure was 25 MPa, 30 MPa, and 40 MPa, the extraction temperature was 50 ° C and the same separation conditions (separation kettle I pressure was 10 MPa, temperature was 60 ° C, separation kettle Ⅱ pressure was 6 MPa, temperature was 45 ° C), entrained. Under the condition of 300 ml of 80% ethanol solution, the effects of extraction time of 15, 30, 45, 60, 75, and 90 min on the extraction rate of 10-DAB were investigated.
Generally, with the extension of extraction time, the extraction rate increases accordingly.
Under 3 different extraction pressures, the extraction rate increased rapidly within 45 minutes before the start of extraction. After 45 minutes, the increase in extraction rate was gradually slower, and the extraction was basically complete after 90 minutes.
Effect of Extraction Pressure on Taxus 10-DAB Extraction Rate
Extraction of Taxus 10-DAB with supercritical CO2, extraction pressure is one of the main factors affecting extraction rate. Under the three different extraction temperature conditions of 45 ° C, 50 ° C and 60 ° C, the extraction time of the remaining conditions is 90min, the entrainer is 300ml of 80% ethanol solution, and the same separation conditions (separation kettle I pressure is 10Mpa, temperature is At 60 ° C, the pressure of the separation tank II was 6 MPa, and the temperature was 45 ° C), the effects of the four levels of extraction pressures of 25 MPa, 30 MPa, 35 MPa, and 40 MPa on the 10-DAB extraction rate were examined.
Under three different temperature conditions, as the extraction pressure gradually increased, the extraction rate also increased. When the pressure exceeded 30 MPa, the 10-DAB extraction rate decreased. The solubility of supercritical CO2 fluids generally increases with increasing density, and its density depends on pressure. Other conditions remain the same, the pressure increases to increase the density and enhance the ability to dissolve. However, when the pressure is too high, the raw material powder may be compacted and agglomerate, which hinders the mass transfer , and reduces the 10-DAB extraction rate. It can be determined that the optimal extraction pressure is 30 MPa.
Effect of Extraction Temperature on the Extraction Rate of Taxus 10-DAB
During supercritical CO2 extraction, the extraction temperature has a dual effect on paclitaxel extraction. Increasing temperature will intensify the molecular movement in the system, improve the mass transfer between the solvent and the raw materials, and also reduce the density of the CO2 fluid and reduce the dissolving ability . In this experiment, under the conditions of extraction pressure of 30 MPa, extraction time of 90 min, 300 ml of 80% ethanol solution as entrainer, pressure of 10 MPa in separation kettle I, temperature of 60 ℃, pressure of 6 MPa in separation kettle II, temperature of 45 ℃, examine 40 ℃, The effect of the extraction temperature at 50 ℃, 55 ℃ and 60 ℃ on the yield of 10-DAB.
At an extraction pressure of 30 MPa, the temperature increased, the extraction rate of 10-DAB increased first and then decreased, and the extraction rate of 10-DAB reached the highest at 50 ° C.
Effect of Separation Kettle Ⅰ Pressure on Taxus 10-DAB Extraction Rate
This experiment examined different separation kettles under the conditions of extraction pressure of 30MPa, temperature of 50 ° C, separation kettle I temperature of 60 ° C, separation kettle II pressure of 6MPa, temperature of 45 ° C, entrainer of 80% ethanol solution of 300ml, and extraction time of 90min. Ⅰ The effect of pressure on the yield.
The 10-DAB extraction rate is the highest when the pressure in the separation tank I is 10 MPa.
The optimum pressure condition of the separation kettle I is 10 MPa.
Under the conditions of extraction pressure of 30 MPa and temperature of 50 ℃, pressure of separation tank I of 10 MPa, pressure of separation tank II of 6 MPa, temperature of 45 ℃, entrainer of 300% 80% ethanol solution, extraction time of 90 min, different separation tank Ⅰ temperature versus yield Impact.
When the temperature of separation kettle I was 60 ℃, the extraction rate of yew 10-DAB reached the highest.
Optimization of Supercritical CO2 Extraction of Taxus 10-DAB
Based on the results of the single-factor test described above, an orthogonal test was performed, and the 10-DAB extraction rate was used as an evaluation index to optimize the entire extraction process.
From the magnitude of the range R, it can be seen that the influencing factors on the extraction rate are as follows: entrained dose> pressure in the separation kettle I> temperature in the separation kettle I> extraction pressure> extraction temperature
The optimal technological conditions for supercritical CO2 extraction of yew 10-DAB are: extraction kettle pressure 30MPa, extraction kettle temperature 50 ℃, separation kettle I pressure 10MPa, temperature 60 ℃, separation kettle II pressure 6MPa, temperature 45 ℃, entrainer The 80% ethanol solution is 300ml, and the extraction time is 90min.
The optimization was carried out to verify the process conditions, and the results showed that the process was stable.
The optimal process conditions for supercritical CO2 extraction of yew 10-DAB are: pressure of extraction kettle 30MPa, temperature of extraction kettle 50 ° C, pressure of separation kettle I 10MPa, temperature 60 ° C, pressure of separation kettle II 6MPa, temperature 45 ℃, entrainer 300% 80% ethanol solution, extraction time 90min.
The supercritical CO2 extraction method can be used to extract the taxane diterpenoids 10-DAB from Taxus chinensis, and the extraction rate exceeds 40%.
The extracted initial product needs to be separated and purified to obtain high-purity 10-DAB, which needs further analysis and research.