Natural extraction of camptothecin (abbreviated as CPT below) CPT extracted by natural extraction method must be in s configuration to be active. However, the wide application of this method is limited due to the limited natural plant resources containing CPT, the low content of CPT, and the fact that it is easily affected by factors such as season and origin.
According to the research results in the past two years, the natural extraction methods of camptothecin are mainly resin adsorption method, alkali method, supercritical carbon dioxide extraction and other methods.
Some studies have established the optimized process of extracting and purifying camptothecin from camptothecin by macroporous adsorption resin: camptothecin powder—soaking in 70% ethanol—concentrating—adding saturated lime water to the concentrate, stirring for 30min and filtering—the filtrate to adjust. pH value 8～9—on AB-8 resin column—90% ethanol elution with pH value 2—3—concentration to suspension—ethyl acetate extraction—concentration, light-proof crystallization—+crude product—ethyl acetate—petroleum Ether (2:3) was dissolved and recrystallized to obtain pure product. The obtained camptothecin has a purity of 98% and a yield of 0.41%.
Advantages of resin adsorption
- The ethanol extract is concentrated and treated with saturated lime water, which can greatly improve the yield of camptothecin, the yield can reach 0.41%o, and at the same time, the impurities are greatly reduced;
- After the resin is eluted with ethanol with a pH value of 2~3 and 90%, the ethanol is washed off with tap water, which can be reused, and the treatment is convenient and simple;
- Ethyl acetate: The insoluble matter remaining after extraction with petroleum ether (2:3) contains a large amount of hydroxycamptothecin, and the price of hydroxycamptothecin is about 10 times that of camptothecin, so it can be further processed. purification.
It should be pointed out here that the traditional extraction process of camptothecin uses camptothecin powder as raw material and ethanol as a solvent for extraction. However, using ethanol as a solvent has the characteristics of relatively high cost, long extraction time, large energy consumption, and high fire protection requirements.
In order to overcome the above defects, people have discussed using dilute NaOH solution as the solvent, the extraction reaction is carried out at room temperature, the extraction time is short, and the extraction rate is also high. Camptothecin can react with NaOH solution at room temperature, open the ring to form sodium salt and dissolve in alkaline water, and then close the ring to become the original alkaloid after adjusting the acid, using a 1.5% concentration of NaOH water After the liquid immersion, the 0.3% NaOH aqueous solution was used to extract camptothecin from the camptothecin fruit, which replaced the original alcohol extraction process.
Alkaline extraction does not require a large amount of ethanol and reduces the amount of chloroform. The material consumption and energy consumption associated with the production process are relatively much lower. At the same time, it also simplifies unit operations such as concentration and recovery of ethanol and ether degreasing in the process flow. The actual production cost per kilogram The average has dropped a lot, bringing better economic benefits.
Changes in Extracted Materials
The traditional extraction process of camptothecin is based on the fruit and root bark of Camptotheca.
Using root bark as raw material requires a lot of felling of Camptotheca, and using fruit as raw material is limited by seasons. Studies have shown that the content of camptothecin in Camptotheca fruit is generally about 0.1%, and the root and root bark are even lower.
Camptothecin content in camptothecin leaves, especially young leaves, is very high (0.1142%). Wang Yang et al. conducted experiments using the leaves as raw materials, and determined the optimal process conditions for alkaline extraction: the concentration of NaOH solution was 0.3%, the extraction time was 3h, and the amount of NaOH solution was 16ml/(g·times).
The experimental extraction rate also reached more than 0.1%.
The supercritical CO2 extraction process
It will be the future development direction to study the use of modern technology to extract the anti-cancer active components in Camptotheca and to explore the comprehensive extraction method of various anti-cancer active components of Camptotheca. An in-depth understanding of the active chemical components of Camptotheca and the efficient extraction and separation of the active components such as camptothecin is the current research hotspots of Camptotheca, and a lot of research has been carried out in this area.
Among them, supercritical carbon dioxide extraction technology is a fast, cheap, non-toxic, non-polluting, low-temperature, and high-efficiency method. In the experiment, the supercritical carbon dioxide fluid extraction method and macroporous adsorption resin were used to extract camptothecin from camptothecin fruit, and fatty acid components such as linolenic acid, oleic acid, palmitic acid, and linoleic acid were also obtained. Linolenic acid, oleic acid, and palmitic acid have also been confirmed to have anticancer effects, which can significantly prolong the lifespan of mice with tumors. The camptothecin raw material is put into the CO2 extraction machine to first extract palmitic acid and linoleic acid. After taking out the mixture of palmitic acid and linoleic acid from the separation kettle, the extraction of camptothecin is continued. Reducing the operation links can not only reduce the loss of raw materials but also save a lot of working time and greatly improve the working efficiency. The yield of camptothecin is 0.025%, the purity is 97.8%, and the yield of fatty acid is 1.8 %.
Advantages of supercritical carbon dioxide extraction
- In the extraction stage, supercritical carbon dioxide extraction can save a lot of time. Traditional methods generally require tens of hours of soaking, while supercritical carbon dioxide extraction only takes a few hours, which is suitable for large-scale production.
- The percolation process of the traditional method consumes a lot of organic solvents and pollutes the environment. The supercritical carbon dioxide extraction method can completely avoid solvent pollution.
- The use of supercritical carbon dioxide extraction can reduce the time-consuming and labor-intensive process of solvent concentration under reduced pressure.
- The macroporous adsorption resin purification process can greatly reduce the consumption of chloroform and simplify the product refining process.
- At the same time, fatty acid products such as linolenic acid can be obtained.