CN1880342A - Process for extracting polysaccharide from astragalus root using microwave - Google Patents

Abstract

This invention discloses a method for extracting Radix Astragali polysaccharide by microwave from Radix Astragali, comprising: 1) extract the Radix Astragali in water using microwave at constant temperature of 40-100Deg C; 2) collect the extracting liquid, filtrate, concentrate and precipitate by adding ethanol; 3) centrifuge and dry the sediment so as to obtain the Radix Astragali polysaccharide. This invention can control the microwave extraction at certain constant temperature continuously without break between each extraction, and is characterized of high selectivity, simple procedures, low consumption of labor and energy, high yield, and high purity.

Description

Microwave Extraction Method of Astragalus Polysaccharide

technical field

The invention relates to a microwave extraction method of traditional Chinese medicine, in particular to a method for extracting astragalus polysaccharide from astragalus by adopting microwave technology.

Background technique

Radix Astragalus (Radix Astragalus) is the dried root of Astragalus membranaceus (Fisch) Bge or Astragalus membranaceus (Fisch) Bge.Var.mongholicus (Bge) Hsiao) of the leguminous plant. Sweet in taste, slightly warm in nature, invigorating qi and solidifying the surface, diuresis and treating sores. Modern pharmacological studies have shown that astragalus polysaccharide is one of the main components of astragalus, which has a wide range of pharmacological effects such as improving immunity, anti-tumor, anti-radiation damage, antibacterial and anti-virus, regulating blood sugar, and anti-aging.

The microwave extraction method of traditional Chinese medicine does not emit toxic pollutants during the process; in addition, microwave equipment is an electrical equipment that does not need to be equipped with a boiler, is safe and pollution-free, and is a green project. However, there are not many literatures on extracting and separating Astragalus polysaccharides from Astragalus membranaceus by microwave method, such as Wang Li, Liu Zhiyong, Lu Jianjiang, etc. 35.) Use microwave technology to remove fat-soluble impurities from astragalus with petroleum ether and ether, extract with 80% ethanol to remove interfering components such as monosaccharides, oligosaccharides and glycosides, and then put it into the MCL-3 continuous Continue to extract with water reflux in the microwave reactor for 20 minutes, adjust the power to 630W, 600W, 560W, 450W, concentrate under reduced pressure to half the volume, add 0.1% activated carbon to decolorize, filter, add 95% ethanol solution to the filtrate to make the alcohol 80%, let it stand overnight, filtered, and the residue was repeatedly washed with ether and absolute ethanol, and dried to obtain the crude product of astragalus polysaccharide with a content of 6.55%.

Gong Shengzhao, Yang Zhuoru (Study on Microwave-Assisted Extraction of Astragalus Polysaccharides [J]. Journal of South China University of Technology (Natural Science Edition), 2004, 32(8): 93-96) Using water as the extractant, studied the microwave-assisted extraction of Astragalus The process of polysaccharides obtained the best process conditions for microwave-assisted extraction of astragalus polysaccharides: the mass ratio of liquid to material is 12:1; the optimum pH is adjusted to 9 with saturated lime water; the microwave power is 300W for 2 extractions; Microwave for 1 minute, pause for 1 minute, and then turn on for 1 minute, repeating this 10 times in total, that is, the total time for each extraction is 19 minutes, of which the actual microwave extraction time is 10 minutes. After the extract was concentrated in vacuum, ethanol was added to precipitate the polysaccharide, filtered, the precipitate was washed with ethanol for several times, and after vacuum drying, the astragalus crude polysaccharide was obtained with a yield of 14.6% and a purity of 88.1%.

It can be seen that the above-mentioned existing microwave extraction methods exist: ① impurities must be removed before extraction; ② the extraction power must always be ≥ 300W, and the microwave reactor must be turned on and off repeatedly. Therefore cause problems such as too many operation steps, too numerous and diverse and waste of energy.

Contents of the invention

Aiming at the problems that there are too many operating steps in the above method, too complicated and too much power to cause energy waste, we have improved the extraction method to simplify the microwave extraction steps without causing energy waste, and the obtained Radix Astragali Polysaccharide content or extraction rate are higher. Therefore, the purpose of the present invention is to provide a new method for microwave extraction of astragalus polysaccharide.

The technical scheme of the present invention is: a method for microwave extraction of astragalus polysaccharides from astragalus, which comprises the following steps:

1) Carrying out constant-temperature microwave extraction of Astragali medicinal materials in water, the temperature is selected from 40-100°C;

2) Collect the extract, filter, concentrate, add ethanol to obtain the precipitate;

3) The astragalus polysaccharide of the present invention is obtained by centrifuging and drying the obtained precipitate.

The constant-temperature microwave extraction in the present invention means that the reaction temperature of the microwave extraction equipment is directly controlled at a certain point during each extraction, and the power of the microwave extraction equipment is automatically adjusted to perform continuous extraction, without the need to continuously artificially adjust the microwave power or perform intermittent extraction. It can be seen that any microwave reaction device or extraction (extraction) extraction equipment that can control temperature and automatically adjust power can be used in the present invention, such as: WF-4000C (atmospheric pressure microwave reaction system, Shanghai Yiyao Analytical Instrument Co., Ltd.); WF -4000M (closed microwave reaction system, Shanghai Yiyao Analytical Instrument Co., Ltd.) MAS-I type (atmospheric pressure microwave-assisted synthesis/extraction reaction instrument, Shanghai Xinyi Microwave Chemical Technology Co., Ltd.); Temperature and pressure dual control microwave digestion/extraction instrument, Shanghai Xinyi Microwave Chemical Technology Co., Ltd.); MDS-2002AT (temperature, pressure dual control microwave digestion/extraction instrument, Shanghai Xinyi Microwave Chemical Technology Co., Ltd.), etc. The present invention selects WTS03-1 type microwave extraction equipment. When extraction is carried out at a certain temperature in the above range, except for the short initial stage when the temperature is reached, the power of the equipment is below 200W in the remaining extraction stages.

Wherein, the number of times of extraction mentioned in step 1) is 1 to 10 times, 5 to 30 minutes each time, and 5 to 25 times the weight of water is added each time.

Preferably, the above-mentioned temperature in the present invention is selected from 60-90°C, microwave extraction is performed 2-6 times, each time is 8-20 minutes, and 6-15 times of water is added each time.

More preferably, the temperature is 68-72°C, microwave extraction is performed 3-4 times, 10 minutes each time, 11 times the amount of water is added for the first time, and 8 times the amount of water is added each time thereafter.

Preferably, the water mentioned in step 1) of the present invention may also contain acid or alkali, and its pH is adjusted to 4-8. Said acid or base is preferably an inorganic acid or base, such as hydrochloric acid, sulfuric acid, potassium hydroxide, sodium hydroxide or ammonia water and the like. Usually, 0.5-10% dilute acid or 0.5-5% dilute alkali can be used.

Steps 2) and 3) of the method of the present invention can use any conventional methods and steps for the separation and purification of astragalus polysaccharides. Preferably, the addition of ethanol to obtain precipitation (referred to as alcohol precipitation) in step 2) can be repeated twice or twice. more than times.

The Radix Astragali medicinal material of the present invention can be selected in various properties such as slices, blocks and powders, and the medicinal medicinal material Radix Astragali is preferably powdered.

Compared with the existing technology, the present invention has the following advantages: the steps are simple, there is no need to continuously artificially adjust the microwave power or perform intermittent extraction, which reduces manpower consumption; the microwave power of the present invention is maintained below 200W most of the time, reducing energy consumption; In addition, the ethanol used in the alcohol precipitation can be recycled and used repeatedly; therefore, the method of the invention can greatly reduce the cost. In addition, the present invention is simple to operate, does not need to go through the column, and the microwave extraction can greatly shorten the extraction time to 20 minutes. And the extraction rate of the inventive method is high: generally can be greater than 14%; And extraction reaction condition is controllable, promptly selectivity is good, thereby can repeatedly prepare the product of high purity (all exceeding 50%, the highest greater than 87%).

Detailed ways

The present invention is further illustrated below by way of examples. It should be understood that the embodiments of the present invention are used to illustrate the present invention rather than limit the present invention. The simple improvements made to the present invention according to the essence of the present invention all belong to the protection scope of the present invention. In addition, in the present invention, (w/w) represents a weight percentage concentration or a weight ratio.

Among them, the Astragalus medicinal material selected in the following examples is produced in Hunyuan, Shanxi, and passed through 20 meshes; the microwave extraction equipment is WTS03-1 type (Nanjing Jiequan Microwave Equipment Co., Ltd.). The purity of obtained astragalus polysaccharide was measured by phenol-sulfuric acid method.

Example 1

Precisely weigh 10g of astragalus powder, put it in a microwave extraction equipment, add water 114ml for the first time, and then add water 80ml each time, control the temperature at 70°C, and extract 4 times in total, 10min each time. Collect the extract, filter with gauze and absorbent cotton, collect the filtrate, concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, add 150ml of water to the precipitate, stir to dissolve, centrifuge, take the supernatant and concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, Dried to obtain 1.4 g of astragalus polysaccharide with a purity of 87.14%, with a yield of 14%.

Example 2

Accurately weigh 5g of astragalus powder, put it in a microwave extraction equipment, add 50ml of dilute hydrochloric acid solution for the first time, and then add 25ml of dilute hydrochloric acid solution each time, control the pH to 4, and control the temperature to 40°C, extract 8 times in total, 5min each time . Collect the extract, filter with gauze and absorbent cotton, collect the filtrate, concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, add 150ml of water to the precipitate, stir to dissolve, centrifuge, take the supernatant and concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, Dried to obtain 1.02 g of astragalus polysaccharide with a purity of 60.23%, and a yield of 20.4%.

Example 3

Accurately weigh 20 g of astragalus powder, put it in a microwave extraction equipment, add 500 ml of ammonia solution, control the pH to 8, and control the temperature at 100 ° C, and extract once for 30 min. Collect the extract, filter with gauze and absorbent cotton, collect the filtrate, concentrate to 13ml, add 40ml of ethanol to stir, centrifuge, add 240ml of water to the precipitate, stir to dissolve it, centrifuge, take the supernatant and concentrate to 13ml, add 40ml of ethanol to stir, centrifuge, Dried to obtain 3.17 g of astragalus polysaccharides with a purity of 75.56%, and a yield of 15.85%.

Example 4

Precisely weigh 15g of astragalus powder, put it in a microwave extraction equipment, add 225ml of dilute sulfuric acid solution for the first time, and then add 200ml of dilute sulfuric acid solution each time, control the pH to 5, and control the temperature to 60°C, extract 6 times in total, each time 8min . Collect the extract, filter with gauze and absorbent cotton, collect the filtrate, concentrate to 13ml, add 55ml of ethanol to stir, centrifuge, add 230ml of water to the precipitate, stir to dissolve, centrifuge, take the supernatant and concentrate to 13ml, add 55ml of ethanol to stir, centrifuge, Dried to obtain 2.46 grams of astragalus polysaccharides with a purity of 64.78%, and a yield of 16.4%.

Example 5

Accurately weigh 10g of astragalus powder, put it in a microwave extraction equipment, add 120ml of dilute sodium hydroxide aqueous solution for the first time, and then add 80ml of sodium hydroxide aqueous solution, control the pH to 8, and control the temperature to 90°C, and extract twice in total. 20 minutes each time. Collect the extract, filter with gauze and absorbent cotton, collect the filtrate, concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, add 150ml of water to the precipitate, stir to dissolve, centrifuge, take the supernatant and concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, Dried to obtain 1.48 g of astragalus polysaccharides with a purity of 80.12%, and a yield of 14.8%.

Example 6

Precisely weigh 10g of astragalus powder, put it in a microwave extraction equipment, add 120ml of potassium hydroxide aqueous solution for the first time, and then add 80ml of potassium hydroxide aqueous solution each time, control the pH to 8, and control the temperature at 60°C, and extract 3 times in total. 10 minutes each time. Collect the extract, filter with gauze and absorbent cotton, collect the filtrate, concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, add 150ml of water to the precipitate, stir to dissolve, centrifuge, take the supernatant and concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, Dried to obtain 1.56 g of astragalus polysaccharide with a purity of 67.84%, and a yield of 15.6%.

Example 7

Precisely weigh 10g of astragalus powder, put it in microwave extraction equipment, add 120ml of water for the first time, add 80ml of water for the second time, control the temperature at 60°C, and extract 3 times in total, 10min each time. Collect the extract, filter with gauze and absorbent cotton, collect the filtrate, concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, add 150ml of water to the precipitate, stir to dissolve, centrifuge, take the supernatant and concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, Dried to obtain 1.53 g of astragalus polysaccharide with a purity of 66.78%, and a yield of 15.29%.

Example 8

Precisely weigh 10g of astragalus powder, put it in microwave extraction equipment, add 120ml of water for the first time, add 80ml of water for the second time, control the temperature at 70°C, and extract 2 times, each time for 20min. Collect the extract, filter with gauze and absorbent cotton, collect the filtrate, concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, add 150ml of water to the precipitate, stir to dissolve, centrifuge, take the supernatant and concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, Dried to obtain 1.286 g of astragalus polysaccharide with a purity of 78.74%, and a yield of 12.86%.

Example 9

Precisely weigh 10g of astragalus powder, put it in microwave extraction equipment, add 120ml of water for the first time, add 80ml of water for the second time, control the temperature at 50°C, and extract 3 times in total, 20min each time. Collect the extract, filter with gauze and absorbent cotton, collect the filtrate, concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, add 150ml of water to the precipitate, stir to dissolve, centrifuge, take the supernatant and concentrate to 10ml, add 50ml of ethanol to stir, centrifuge, Dried to obtain 0.925 g of astragalus polysaccharide with a purity of 66.54%, and a yield of 9.25%.

Claims (10)

1. A method for microwave extraction of astragalus polysaccharides from astragalus, comprising the following steps: 1) Carrying out constant-temperature microwave extraction of Astragali medicinal materials in water, the temperature is selected from 40-100°C; 2) Collect the extract, filter, concentrate, add ethanol to obtain the precipitate; 3) The astragalus polysaccharide of the present invention is obtained by centrifuging and drying the obtained precipitate. 2. The method according to claim 1, characterized in that the extraction times in step 1) are 1-10 times, each time is 5-30 minutes, and 5-25 times the weight of water is added each time. 3. The method according to claim 2, characterized in that in step 1), the temperature is selected from 60-90°C, 2-6 times of microwave extraction, 8-20 minutes each time, and 6-15 times of water is added each time. 4. The method according to claim 3, characterized in that the temperature is 68-72°C, microwave extraction is performed 3-4 times, 10 minutes each time, adding 11 times the amount of water for the first time, and adding 8 times the amount of water each time thereafter. 5. The method according to claim 1, characterized in that the water in step 1) also contains acid or alkali, and its pH is 4-8. 6. The method of claim 5, wherein the acid or base is an inorganic acid or base. 7. The method of claim 6, wherein the mineral acid is hydrochloric acid or sulfuric acid. 8. The method as claimed in claim 6, characterized in that the inorganic base is potassium hydroxide, sodium hydroxide or ammonia water. 9. The method according to claim 1, characterized in that the step 2) of adding ethanol to obtain precipitation can be repeated 2 or more times. 10. The method according to any one of claims 1-9, characterized in that the Astragalus medicinal material is its powder.