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Supercritical CO2 extraction of Magnolia officinalis

Magnolia

Magnolia officinalis is the dry dry bark, root bark and branch bark of Magnolia officinalis. It has the functions of drying dampness, eliminating phlegm, lowering qi and eliminating fullness. It is used for damp stagnation, vomiting and diarrhea, stagnation of qi in food, abdominal distension, constipation, Phlegm, wheezing and coughing.

Supercritical CO2 extraction of Magnolia officinalis
Supercritical CO2 extraction of Magnolia officinalis

The “Chinese Pharmacopoeia” stipulates that the total amount of its main components magnolol and honokiol shall not be less than 2%.

Supercritical CO2 extraction

Magnolia officinalis has a variety of pharmacological activities. There are many literatures related to supercritical CO2 extraction and separation of Magnolia officinalis. There is no report on the combined extraction of Magnolia officinalis with supercritical CO2. Therefore, this experiment is based on the main active ingredients of Magnolia officinalis. The amount and extraction rate of nokiol and honokiol were the main indicators to be investigated. Parallel experiments were conducted to compare the effects of ultrasound-enhanced supercritical extraction, ultrasound alone, and supercritical extraction. Provide a reference for exploring the application research of ultrasound-enhanced supercritical extraction.

Extraction of Magnolol and Honokiol

Take Magnolia officinalis medicinal materials, smash, pass through a 100-mesh sieve, and mix; refer to the stable process parameters of Magnolia officinalis supercritical extraction (SFE), and use the method of parallel testing to compare the effects of ultrasound, supercritical and ultrasound-enhanced supercritical extraction.
Ultrasonic extraction Take 100.02g of Magnolia officinalis powder and place it in a 1L extraction kettle. Add 4 times the amount of ethanol to ultrasonically extract for 2h (1kW, working intermittently for 2min). Collect the ethanol extract from the discharge port and recover it under reduced pressure at 50°C until no ethanol drips. , Get extract.

SFE takes 100.01g of Magnolia officinalis powder, puts it in a 1L extraction kettle, and extracts for 2h under the following conditions: extraction pressure 18MPa, extraction temperature 35°C, separation pressure 5MPa, separation temperature 40°C, to obtain an extract.

Supercritical and co-solvent extraction Take 100.02g of Magnolia officinalis powder and add twice the amount of ethanol.

Ultrasonic-enhanced supercritical extraction (USFE) takes 100.02g of Magnolia officinalis powder, ultrasonically enhanced (1kW, intermittent work for 2min), and processes it for 1.5h under the conditions of “2.1.2”.
Ultrasound-enhanced supercritical and co-solvent extraction (USFE/E) Take 100.08g of Magnolia officinalis powder, add 1.5 times the amount of ethanol, and treat it under the conditions of “2.1.4”.

Determination of Magnolol and Honokiol

Preparation of reference substance solution Accurately weigh the appropriate amount of magnolol and honokiol reference substance, and prepare a mixed reference substance solution containing magnolol 48μg/mL and honokiol 24.52μg/mL with methanol.

Preparation of test solution: Take 0.1g of each extract under “2.1”, accurately weigh it, place it in a 25mL measuring flask, add 95% ethanol to dissolve and dilute to the mark, shake well, filter, and get it.

Chromatographic conditions: Chromatographic column is Kromasil100-5C18 (250mm×4.6mm, 5μm), plus pre-column; mobile phase is methanol-water (78:22); volume flow rate is 1.0mL/min, column temperature is 30°C, sample volume is 10μL, The detection wavelength is 294nm.

Linear relationship investigation Precisely measure 1, 2.5, 5, 10, 15, 20 μL of the above-mentioned mixed reference solution, and inject it into the liquid chromatograph, measure the peak area, take the peak area as the ordinate and the sample volume as the abscissa, and perform linear regression

Sample determination

Precisely draw 10μL each of the above-mentioned reference substance and test solution, and inject it into the liquid chromatograph, determine and calculate the amount of magnolol and honokiol in each extract, and calculate the extraction rate (extraction rate=extract mass× The mass fraction of the tested component in the extract/the quantity of the tested component in the medicinal material). . It can be seen that ultrasound-enhanced supercritical has obvious advantages over the two separate extractions, and the amount and extraction rate of magnolol and honokiol in the extract are significantly increased.

Ultrasonic enhanced supercritical extraction process optimization

Using the amount of magnolol and honokiol in the extract and its extraction rate as an indicator, the process parameters affecting the ultrasonic enhanced supercritical extraction: extraction temperature, extraction time, ultrasonic intensity and co-solvent dosage are considered, taking into account the work of this device Therefore, the extraction pressure is set to 18MPa.

Extraction temperature

The fixed co-solvent ethanol was used at twice the amount, the extraction time was 2h, the ultrasonic intensity was 1kW, and the extraction temperature was 35, 45, 55 ℃, respectively, on the effect of the extraction.

It can be seen that when the extraction temperature is 45°C, the amount and extraction rate of magnolol and honokiol are the largest. Therefore, the extraction temperature is selected to be 45°C.

Extraction time

The extraction temperature was fixed at 45°C, the amount of co-solvent ethanol was doubled, and the ultrasonic intensity was 1kW. The effects of extraction time were 60, 90, and 120 minutes on the extraction effect.

It can be seen that when extracting 90min and 120min, magnolol and
The amount of magnolol and the extraction rate are not much different. From the perspective of saving time and energy consumption, the extraction time is selected as 90 minutes.

Ultrasonic intensity

The fixed extraction temperature is 45℃, the amount of co-solvent ethanol is doubled, and the extraction time is 90min; because this device is designed to set the ultrasonic intensity to 4 gears (respectively 0.2, 0.5, 1, 2kW), investigate the above 4 kinds of ultrasonic intensities The impact on the extraction effect.

It can be seen that when the ultrasonic intensity is 1kW, the amount and extraction rate of magnolol and honokiol are higher, and the intensity continues to increase, and the medicinal materials are severely crushed, which is not conducive to extraction, so the ultrasonic intensity is selected as 1kW.

Co-solvent dosage

The extraction temperature was fixed at 45℃, the extraction time was 1.5h, and the ultrasonic intensity was 1kW. The effects of the co-solvent ethanol dosages were 0.25, 0.5, 1.0, 1.5, and 2.0 times on the extraction effect.

It can be seen that when the amount of cosolvent ethanol is doubled, the amount and extraction rate of magnolol and honokiol are higher. If the amount of cosolvent continues to be increased, the changes in the two indicators are not obvious. In order to save solvent and reduce the difficulty of recovery, Therefore, the amount of co-solvent ethanol is 1 times the amount.

Discuss

Studies have shown that supercritical extraction and ultrasonic extraction technology have broad application prospects in the extraction and separation of traditional Chinese medicine. The successful combination of the two has positive significance for the extraction and purification of the active ingredients of Magnolia officinalis and the research of preparation technology. It is also used for other traditional Chinese medicines. Product process improvement provides new methods.

The study found that when the ultrasonic intensity increases to 1kW, the supercritical strengthening effect is the most obvious. When the ultrasonic intensity continues to increase, the ultrasonic smashing effect on the medicinal materials is serious, and a large amount of medicinal powder is washed out of the extraction kettle with the CO2 fluid, resulting in separation in the kettle Containing a large amount of powder, the extraction rate of magnolol and honokiol is significantly reduced.

The supercritical fluid extraction technology largely avoids the shortcomings of the traditional extraction process, and is an environmentally friendly green extraction technology.

However, this technology also has some problems that need to be solved, such as high-pressure operation requires high equipment, and the extraction efficiency needs to be further improved.

Ultrasound can produce a cavitation effect, which has special effects such as crushing, stirring, emulsification, etc., so that the cavitation bubbles produced by plant tissues in the solvent are collapsed, and the cells in the tissues are broken, so that the solvent can penetrate into the plant cells and make the plants The active ingredients are dissolved in the solvent.

The combined use of ultrasound and supercritical reduces the extraction pressure and the amount of co-solvent to a certain extent.