阅读说明：本技术 一种靛苷的制备方法 (Preparation method of indican ) 是由 高旻天 于 2021-09-08 设计创作，主要内容包括：本发明公开了一种靛苷的制备方法,包括以下步骤：将蓝草叶片在-15℃～0℃的有机溶剂中浸泡10～30min；②将水加热至80℃～100℃,将步骤①浸泡后的蓝草叶片加入热水中浸取10～30min,去除叶片,得浸取液；③向步骤②得到的浸取液中投加新鲜的有机溶剂低温浸泡处理的蓝草叶片,在80℃～100℃下浸取10～30min,得靛苷浓度更高的浸取液；④重复步骤③的操作2～5次,得到高浓度的靛苷浸取液；⑤提纯得到靛苷纯品。本申请设置的提取条件,能够从含靛苷的植物中提取到以靛苷为主体的生物活性物质,产率高,本发明方法可推广至其它含靛苷中草药中活性成分靛苷的提取,有利于提高相关中药资源的利用。(The invention discloses a preparation method of indican, which comprises the following steps: soaking the blue grass leaves in an organic solvent at the temperature of-15-0 ℃ for 10-30 min; secondly, heating water to 80-100 ℃, adding the soaked blue grass leaves in the first step into hot water for soaking for 10-30 min, and removing the leaves to obtain a leaching solution; thirdly, adding a fresh organic solvent into the leaching solution obtained in the second step, soaking the blue grass leaves at a low temperature, and leaching for 10-30 min at 80-100 ℃ to obtain a leaching solution with higher concentration of the indican; fourthly, repeating the operation of the third step for 2-5 times to obtain high-concentration indigoid leaching solution; fifthly, purifying to obtain pure product of the indican. The extraction conditions set by the method can be used for extracting bioactive substances taking the indican as a main body from the indican-containing plants, the yield is high, the method can be popularized to the extraction of the active ingredient indican in other indican-containing Chinese herbal medicines, and the utilization of related Chinese herbal medicine resources is improved.)

1. A method for preparing indican is characterized by comprising the following steps:

soaking indigo leaf containing indican in an organic solvent at the temperature of-15-0 ℃ for 10-30 min, and then taking out;

secondly, heating water to 80-100 ℃, adding the soaked blue grass leaves into the hot water, soaking at 80-100 ℃ for 10-30 min, and removing the leaves through solid-liquid separation after the soaking is finished to obtain a leaching solution;

adding fresh organic solvent into the leaching solution obtained in the step two, soaking the blue grass leaves at low temperature for 10-30 min at 80-100 ℃, and removing the leaves through solid-liquid separation after the leaching is finished to obtain a leaching solution with higher concentration of the indican;

fourthly, repeating the operation of the third step for 2-5 times to obtain high-concentration indigoid leaching solution;

fifthly, purifying the indigoid leaching solution obtained in the step IV to obtain a pure product of the indigoid.

2. The process for the preparation of indican according to claim 1, characterized in that: the organic solvent is methanol, ethanol or acetone.

3. The process for the preparation of indican according to claim 1, characterized in that: the indigo leaf containing indigo is Polygonum tinctorium, Isatis tinctorium, Indigofera tinctoria or Indigofera tinctoria.

4. The process for the preparation of indican according to claim 1, characterized in that: heating water to 90-100 ℃, and leaching the indigoid glycoside at 90-100 ℃ in the steps II, III and IV.

5. The process for the preparation of indican according to claim 1, characterized in that: in the second step, the third step and the fourth step, 10-50 g of the blue grass leaves are added into every 1L of water when the blue grass leaves are added.

6. The process for the preparation of indican according to claim 1, characterized in that: in the fifth step, adding macroporous resin into the high-concentration indigoid leaching solution obtained in the fourth step, collecting the adsorbed macroporous resin, eluting with 10%, 30%, 50% and 75% ethanol respectively, collecting the eluent, spin-drying the ethanol, and freeze-drying to obtain the indigoid powder.

Technical Field

The invention relates to a method for extracting active substances in plants, in particular to a method for preparing indican.

Background

Indigoside (also called indoxyl-beta-D-glucoside) exists in the leaves of isatis tinctoria, Indigofera tinctoria and the like, consists of indole and glucose, and is a water-soluble colorless transparent compound with the structural formula as follows:

。

when leaves of isatis tinctoria, Indigofera tinctoria and other plants are damaged, the indigoside is released from cell vacuoles and hydrolyzed into indole and glucose through enzymolysis reaction; indole generates indoxyl, the indoxyl generates an autoxidation reaction in the air to generate indigo, and meanwhile, the indoxyl generates condensation reaction under an alkaline condition to generate the indigo. The indigoside is thus the precursor substance for indigo production. In addition, the indigoid glycoside has strong inhibitory action on viruses and pathogenic bacteria, and is an important component of traditional Chinese medicines such as isatis root and the like. However, the main components extracted from the isatis root are indigo and indirubin by the existing extraction method and conditions of the isatis root, and the indioside is not the main component of the isatis root related medicines.

Chinese patent document CN 101701028B (application No. 200910113500.5) discloses a method for preparing indole glycoside, which comprises the following steps: a. extracting folium Isatidis with 8 times of water for 3 times, each for 0.5 hr, mixing extractive solutions, standing overnight, and collecting supernatant; b. diluting with water, ultrafiltering with hollow fiber membrane at room temperature under 0.1MPa for 3 times, mixing ultrafiltrates, and concentrating with nanofiltration membrane; c. continuously concentrating the concentrated solution at 70 deg.C with rotary evaporator, adding into macroporous resin, performing gradient elution with water and ethanol, collecting ethanol eluate, recovering ethanol, concentrating to obtain fluid extract, diluting with 50ml distilled water, extracting with equal amount of diethyl ether for 3 times, and separating to obtain water layer; the gradient elution is that water is firstly used for elution, and then 20 percent ethanol is used for elution; the macroporous resin is AB-8, X-5, DM301, DM130 type macroporous resin; d. adding 2 times of ethyl acetate, performing hot reflux for 5-6 hours, collecting an ethyl acetate layer, concentrating under reduced pressure to one tenth volume, standing at room temperature for crystallization, and filtering to obtain a crude product of the indole glycoside; e. dissolving in hot water, filtering, cooling, crystallizing, and repeating for 5 times to obtain off-white amorphous crystal powder.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a preparation method of the indican with low extraction cost and high yield.

The technical scheme for realizing the aim of the invention is a preparation method of the indican, which comprises the following steps:

firstly, soaking the indigo leaf containing the indican in an organic solvent at the temperature of-15-0 ℃ for 10-30 min, and then taking out.

Secondly, heating water to 80-100 ℃, adding the soaked blue grass leaves into the hot water, soaking for 10-30 min at 80-100 ℃, and removing the leaves through solid-liquid separation after the soaking is finished to obtain a leaching solution.

And thirdly, adding a fresh organic solvent into the leaching solution obtained in the second step, soaking the blue grass leaves at a low temperature for 10-30 min at 80-100 ℃, and removing the leaves through solid-liquid separation after the leaching is finished to obtain the leaching solution with higher concentration of the indican.

And fourthly, repeating the operation of the third step for 2-5 times to obtain the high-concentration indigoid leaching solution.

Fifthly, purifying the indigoid leaching solution obtained in the step IV to obtain a pure product of the indigoid.

The organic solvent is methanol, ethanol or acetone.

The indigo leaf containing indigo is Polygonum tinctorium, Isatis tinctorium, Indigofera tinctoria or Indigofera tinctoria.

Further, heating water to 90-100 ℃, and leaching the indigoid glycoside at 90-100 ℃ in the steps II, III and IV.

In the second step, the third step and the fourth step, 10-50 g of the blue grass leaves are added into every 1L of water when the blue grass leaves are added.

In the fifth step, adding macroporous resin into the high-concentration indigoid leaching solution obtained in the fourth step, collecting the adsorbed macroporous resin, eluting with 10%, 30%, 50% and 75% ethanol respectively, collecting the eluent, spin-drying the ethanol, and freeze-drying to obtain the indigoid powder.

The invention has the positive effects that:

(1) the extraction conditions set by the method can be used for extracting the bioactive substances taking the indican as the main body from the plant containing the indican, and the method can be popularized to the extraction of the active ingredient indican in other Chinese herbal medicines containing the indican, and is beneficial to improving the utilization of related Chinese herbal medicine resources.

(2) In the research and development process of the invention, the difference of the heat stability of the indican and the glucosidase is researched, found and proposed, the enzyme activity is firstly passivated, then the water temperature is controlled to be above 80 ℃ in advance, and then the passivated bluegrass leaves are added, the indican is successfully extracted from the bluegrass leaves by boiling the leaves with water, the activity of the glucosidase is effectively inhibited and destroyed while the indican is extracted, and the generation of byproducts such as indoxyl is reduced or avoided.

(3) In order to avoid the generation of a large amount of byproducts caused by the drastic change of water temperature after adding the leaves, the method uses pre-cooled organic solvent to passivate enzyme activity, a small amount of blue grass leaves are added after the water temperature is controlled at 80 ℃ in advance to extract the indican and carry out solid-liquid separation, the steps of adding a small amount of leaves to extract and carrying out solid-liquid separation are repeated, and finally liquid containing high-concentration indican is obtained.

(4) The preparation method has simple steps and low requirements on equipment, and greatly reduces the extraction cost of the indican; the yield of the final extracted indican reaches more than 1.2% (g/g wet leaf weight).

Drawings

FIG. 1 is an HPLC chromatogram of the indicin prepared in example 1.

FIG. 2 is an HPLC chromatogram of the indicin prepared in example 2.

FIG. 3 is an HPLC chromatogram of the indigoid standard.

FIG. 4 is a standard curve for the indican.

FIG. 5 shows the ethanol inactivation assay.

FIG. 6 shows glycoside extraction experiments after ethanol inactivation.

Detailed Description

(example 1)

The preparation method of the indican of the present example comprises the following steps:

cooling the organic solvent to-15 ℃, immersing the blue grass leaves in the organic solvent, soaking for 30min, and taking out the blue grass leaves for treatment.

The organic solvent is an organic solvent that is miscible with water, such as methanol, ethanol, acetone, etc., and in this embodiment, ethanol.

Heating water to 80-100 ℃ (heating water to 80 ℃ in the embodiment), adding the soaked blue grass leaves in the step (i) into hot water, and adding 10-50 g of blue grass leaves (calculated by the weight of fresh blue grass leaves, 50g in the embodiment) into every 1L of water;

leaching at 80 deg.C for 10-30 min (in this example, leaching for 30 min). And after leaching, carrying out solid-liquid separation to remove the leaves to obtain leaching solution.

The blue grass leaves are leaves containing indioside, such as Polygonum tinctorium, Isatis tinctoria, Indigofera tinctoria, Strobilanthes cusia and the like, and the blue grass leaves are Polygonum tinctorium in the embodiment.

Adding fresh organic solvent into the leaching solution obtained in the step two to soak the polygonum tinctorium leaves at low temperature, wherein the adding amount is the same as that in the step two; leaching at 80 deg.C for 10-30 min (in this example, leaching for 30 min). And after the leaching is finished, removing the leaves by solid-liquid separation to obtain a leaching solution with higher concentration of the indican.

And fourthly, repeating the operation of the third step for 2-5 times (repeating for 4 times in the embodiment) to obtain high-concentration indigoid leaching solution to be purified.

Fifthly, mixing the obtained indigo glycoside leaching solution obtained in the step IV according to the ratio of 1: adding pretreated macroporous resin in the proportion of 10, 1:5 and 1: 3; for example, for 50mL of high concentration of the indioside extract, the ratio of 1: 10, 1:5, 1:3, 5, 10, 15g (wet weight) of pretreated macroporous resin is added. Collecting the adsorbed macroporous resin, eluting with 10%, 30%, 50% and 75% ethanol in sequence, collecting the eluate, spin-drying the ethanol, and freeze-drying to obtain the indioside powder.

The powder of the obtained indican in this example was subjected to HPLC analysis, and the HPLC chromatogram is shown in FIG. 1, and the indican yield in this example was 1.28% (g/g wet weight of leaf).

(example 2)

The process for the preparation of the indigoside of this example is otherwise the same as in example 1, except that:

the organic solvent used in the step I is methanol, the temperature is cooled to-10 ℃, and the blue grass blades are immersed in the organic solvent for 15 min.

Step two, heating the water to 90 ℃.

Adding isatis leaf isatis into water of 90 ℃, and adding 40g of isatis leaf into every 1L of water; soaking the leaves of herba Cymbopogonis Citrari at 90 deg.C for 15 min.

Adding fresh organic solvent into the leaching solution obtained in the step two, and soaking the isatis tinctoria leaves at low temperature, wherein 40g of blue grass leaves are added into every 1L of water; soaking at 90 deg.C for 15 min.

In the fourth step, the operation of the third step is repeated for 2 times to obtain high-concentration indigoid leaching solution to be purified.

The powder of the obtained indican in this example was subjected to HPLC analysis, and the HPLC chromatogram is shown in FIG. 2, and the indican yield in this example was 1.40% (g/g wet weight of leaf).

(test example 1 analysis of Indenoside Standard)

HPLC detection conditions: c18 column, using phase a: water, phase B: gradient elution with acetonitrile; the detection wavelength is 240 nm, the column temperature is 30 ℃, and the sample injection amount is 10 uL. Elution conditions: 80% A-20% B0-15 min 1 mL/min.

Under the detection conditions, the HPLC chromatogram of the indigoid standard is shown in FIG. 3, and as can be seen from FIG. 3, the indigoid standard has a characteristic peak at 4.7 min.

In addition, the standard curve of the indican is shown in FIG. 4, and there is a very good linear relationship in the range of indican concentration from 0.02g/L to 0.1g/L, R²=0.9984, indicating that analysis of the indicin this condition is accurate.

(test example 2, Heat stability test)

Thermal stability test of glucosidase in blue grass leaves

The experimental method comprises the following steps: 1g of Polygonum tinctorium leaves are taken and added into a mortar containing 10mL of precooled phosphate buffer (50 mM, pH 7.8), 20mL of 1% (w/w) polyvinylpyrrolidone solution and a small amount of quartz sand, and ground under the ice-bath condition. And after the mixture is uniformly ground, centrifuging the mixture for 10min at 8000rpm to obtain upper enzyme liquid to be detected. The enzyme activity standard yeast is measured at normal temperature (23 ℃), at 45 ℃, at 60 ℃ and at 80 ℃, and the enzyme activity of the supernatant is measured at the same time.

The analysis method comprises the following steps: adding 0.65 mL of water and 0.05 mL of enzyme solution to be tested into 0.2 mL of acetic acid buffer solution with pH 5 and 0.5M, preheating at 45 deg.C for 5min, adding 0.1 mL of 10 mmol/L pNPG-Glu solution, reacting at 45 deg.C for 10min, adding 500. mu.L of 1 mol/L Na₂CO₃The reaction was terminated. The production of 1. mu. mol p-nitrophenol per minute is defined as one unit of enzyme activity, i.e.1U.

Preparing a p-nitrophenol standard curve:

preparing 2 mM p-nitrophenol solution, adding 0, 0.1, 0.2, 0.3, 0.4 and 0.5 mL into 6 test tubes, and supplementingAdding water to 0.7 mL, adding 0.2 mL of 0.5M acetic acid buffer solution with pH 5, adding 0.1 mL of 10 mmol/L pNPG-Glu solution, and adding 500. mu.L of 1 mol/L Na₂CO₃The absorbance value was measured at 420 nm.

Definition of enzyme activity: the enzyme amount required for producing 1. mu. mol of p-nitrophenol per unit volume of time is one enzyme activity.

N represents dilution factor, V represents sample volume (mL), and t represents reaction time (min).

The results of the experiment are shown in the following table:

the activity of the glucosidase is 650.3U at room temperature (23 ℃); when the temperature is raised to 45 ℃, the enzyme activity is also raised to 1024.5U. However, the enzyme activity tends to decrease with further increase in temperature. At 80 ℃, the enzyme activity is reduced to 76.1U. The result shows that the optimum temperature of the enzyme activity is about 45 ℃, the enzyme activity can be destroyed when the temperature is too high, and the enzyme activity is basically inactivated when the temperature is over 80 ℃.

Heat stability test of Di, indigo glycosides

The experimental method comprises the following steps: the indican standard substance is dissolved in 10mL UP water (ultrapure water) to prepare an indican solution with the concentration of 0.1g/L, and 1mL of the indican solution is taken for testing. And putting the residual solution into boiling water at 100 ℃ for 10min, taking out, putting into an ice bath, rapidly cooling, complementing the total volume of the solution to be 9mL, and taking 1mL of sample to be tested.

The analysis method comprises the following steps: c18 column, using phase a: water, phase B: gradient elution with acetonitrile; the detection wavelength is 240 nm, the column temperature is 30 ℃, and the sample injection amount is 10 uL. Elution conditions: 80% A-20% B0-15 min 1 mL/min.

The experimental results are as follows:

the concentration of the uncooked solution of the indican was 0.1 g/L.

After being boiled in water for 10 minutes, the concentration of the indican is 0.1g/L, and the content is not changed, which shows that the indican has good stability under the condition of 100 ℃.

Example 5 enzyme inactivation test

The experimental method comprises the following steps: soaking 1g of fresh Polygonum tinctorium leaves in 100 mL of 60% ethanol solution with the temperature of-15 ℃ and the pH =2 for 30min, taking out, putting the leaves on ice in a mortar, adding 1g of PVP powder and a certain amount of 0.5M acetic acid buffer solution with the pH =5, grinding the leaves in the mortar until the mixture is homogenized, taking out, and fixing the volume to 20 mL; centrifuging the mixed solution at 4 deg.C and 8000rpm for 20 min, and centrifuging to obtain supernatant as crude enzyme solution.

Adding 0.2 mL of 0.5M acetic acid buffer solution with pH =5, 0.65 mL of water and 0.05 mL of enzyme solution to be tested into a test tube, preheating at 25 deg.C for 5min, adding 0.1 mol/L of pNPG-Glu solution, reacting at 25 deg.C for 10min, adding 0.5 mL of 1 mol/L Na₂CO₃The solution stops the reaction, the light absorption value is measured at 420 nm, and the enzyme activity of the beta-glucosidase is calculated.

Taking another 1g of fresh leaves, directly carrying out the same operation without carrying out low-temperature ethanol pre-cooling treatment to determine enzyme activity as a reference, and comparing the enzyme activity difference of the two.

The analysis method comprises the following steps: 0.2 mL of 0.5M acetic acid buffer solution with pH =5 was added with 0.65 mL of water and 0.05 mL of enzyme solution to be assayed, preheated at 45 ℃ for 5min, added with 0.1 mL of 10 mmol/L pNPG-Glu solution, reacted at 45 ℃ for 10min, added with 500. mu.L of 1 mol/L Na₂CO₃The reaction was terminated. The production of 1. mu. mol p-nitrophenol per minute is defined as one unit of enzyme activity, i.e.1U.

The experimental results are as follows: as shown in FIG. 5, the enzyme activity of the untreated leaves was over 600U/g. And the enzyme activity of the leaves subjected to ethanol precooling treatment is reduced to 30U/g. The ethanol precooling can effectively inactivate the enzyme activity.

Example 6 extraction of glycosides after ethanol inactivation experiment)

The experimental method comprises the following steps: soaking fresh leaves 5g x 2 in 100 mL-15 deg.C 60% ethanol solution with pH =2 for 30min, adding the two groups of leaves into 100 mL water and 60% ethanol solution preheated in boiling water for 5min, boiling for 10min, cooling, and measuring the content of supernatant glucoside and indoxyl.

Adding fresh leaves 5g into 100 mL of water preheated for 5min in boiling water, boiling for 10min, cooling, and measuring the content of glucoside and indoxyl in the supernatant.

The analysis method comprises the following steps: c18 column, using phase a: water, phase B: gradient elution with acetonitrile; the detection wavelength is 240 nm, the column temperature is 30 ℃, and the sample injection amount is 10 uL. Elution conditions: 80% A-20% B0-15 min 1 mL/min.

The experimental results are as follows: as shown in FIG. 6, the control group produced a certain amount of indoxyl during the water cooking. This is due to the slower inactivation of beta-glucosidase during the warming process of the leaves. After ethanol precooling treatment, the yield of indoxyl is very low no matter water or ethanol is used for extracting the indoxyl, so that the yield of the indoxyl is greatly improved, and the inactivation effect of enzyme activity is proved.