Extract medicinal ingredients from herbs
At present, researchers in the world mostly use supercritical CO2 fluid extraction technology to extract different kinds of medicinal ingredients in herbal medicines, such as volatile oils, alkaloids, sugars, propanophenols, diospyros, onion derivatives and other ingredients, etc. .
The main factors affecting the supercritical CO2 extraction of herbal medicine
Under a certain pressure, heating up can increase the volatility of the extracted substance, and its concentration in the supercritical CO2 fluid increases, which increases the number of extractions;
But on the other hand, the temperature rise reduces the density of the supercritical CO2 fluid and the dissolving ability decreases, resulting in a decrease in the number of extractions.
Therefore, the temperature effect is more complicated, and the above two aspects need to be considered comprehensively.
When the extraction temperature is constant, increasing the pressure will increase the density of the supercritical CO2 fluid, the strength of the solvent, and the solubility of the solute.
For different substances, the extraction pressure is different.
Extract particle size
The extract particles should be suitable. The smaller the particle size, the larger the contact area with the supercritical CO2 fluid, which is beneficial to increase the extraction speed; but at the same time, too small particle size will block the sieve holes, cause frictional heat, and increase the temperature of the system. Destroyed.
Application of Supercritical Extraction Technology in the Research of Chinese Herbal Medicine
Supercritical CO2 Fluid Extraction of Volatile oil
Supercritical CO2 fluid extraction of evening primrose oil
The supercritical CO2 fluid extracts evening primrose oil from the evening primrose seeds. As a result, the color and transparency of the evening primrose essential oil and the content of y-linolenic acid with significant physiological activity are better than the solvent method.
Supercritical CO2 Fluid Extraction of Volatile Oil from Angelica
Supercritical CO2 fluid extracts the volatile oil of Angelica sinensis. The pressure is 30MPa, the temperature is 44°C, and the time is 3h. The yield is 115%. After GC-MS analysis of the obtained essential oil, a series of alkanes that cannot be obtained by conventional methods are separated and identified for the first time. There are 28 ingredients including glutinous rice, organic acids and esters.
Supercritical CO2 fluid extraction of flavonoids
Flavonoids are rich in resources. Traditional methods mainly use alcohol, alkaline water, alkaline alcohol, hot water, etc. after extraction, and then separate them according to their polarity, acidity, molecular size, and special structure.
However, these methods have the shortcomings of serious pollution, large loss of active ingredients, low efficiency and high cost. Supercritical CO2 fluid extraction technology can overcome the above shortcomings and ensure quality.
For example, an orthogonal experiment was used to investigate the extraction process of sauban and kaempferin from Ginkgo biloba leaves using supercritical CO2 fluid extraction technology. It was found that the extraction temperature was 60°C, the extraction pressure was 42MPa, the static extraction time was 4min, the dynamic extraction volume was 4ml, and the entrainment was 0.2ml. It works best with ethanol.
Supercritical CO2 fluid extraction technology has the advantages of low temperature, rapidity and high efficiency, and is especially suitable for products with few resources, good curative effects, small dosages and high added value.
At the same time, the supercritical CO2 fluid extraction technology is non-toxic and pollution-free, meeting the needs of drug development and production and “green chemistry”, and provides a prerequisite and guarantee for the analysis and quality control of traditional Chinese medicine.
With the continuous development of high-pressure technology, the investment cost of supercritical CO2 fluid extraction technology and equipment will be greatly reduced. Combined with other unit operations, the efficiency will be higher, and it will play a positive role in promoting the modernization of herbal production.