Cistanche deserticola aqueous extract and preparation method thereof

Abstract

The invention relates to the field of plant extraction, and particularly discloses a herba cistanche aqueous extract and a preparation method thereof, and the preparation method comprises the following steps: taking dry herba cistanche, crushing and sieving to obtain herba cistanche powder; the preparation method comprises the following steps: soaking cistanche powder in a soaking solution, applying a high pressure condition of 3.8-4.5 MPa at the same time, after treatment, firstly relieving the pressure to 1.2-1.7 MPa, and after soaking, relieving the pressure to normal pressure to prepare a pretreated mixture; adding a solvent into the pretreated mixture to carry out water extraction treatment to obtain a crude cistanche extracting solution, and then concentrating and drying under reduced pressure to obtain a cistanche water extract; wherein the soaking solution comprises hydroxyl-containing ionic liquid, water and ethylene glycol carbonate; the invention further discloses the cistanche aqueous extract prepared by adopting the method, and the cistanche aqueous extract has the characteristic that the extraction rate of echinacoside and verbascoside is further increased, so that the content of active components in the cistanche aqueous extract, especially the echinacoside and verbascoside, is increased.

Description

Technical Field

[0001] The present application relates to the field of plant extraction applications, and more specifically, to a Cistanche deserticola water extract and a preparation method thereof. Background Art

[0002] Cistanche deserticola, a tall herbaceous plant of the genus Cistanche in the family Orobanchaceae, grows mostly underground, with stems tapering from bottom to top; leaves are broadly ovate, and the upper part of the stem is sparse and narrow, generally lanceolate; inflorescences are spike-shaped, with petals often rolled outward at the edges, pale yellowish white or lavender, often turning brown after drying; fruits are ovoid; seeds are elliptical or nearly ovate, with a net-like, shiny exterior. Cistanche deserticola has a high medicinal value. According to the Compendium of Materia Medica, Cistanche deserticola can be used to treat kidney yang deficiency, blood loss, cold pain in the waist and knees, tinnitus and eye problems, turbidity, frequent urination, metrorrhagia, infertility, and constipation due to dry intestines. Cistanche deserticola can also be used to make porridge and soak in wine. In addition, Cistanche deserticola is also a precious Chinese medicinal material, known as the "desert ginseng", and has a certain economic value.

[0003] Cistanche deserticola water extract, i.e., water-soluble extract of Cistanche deserticola, is a substance obtained from Cistanche deserticola, a traditional Chinese medicine, through a water extraction process. Cistanche deserticola water extract is rich in a variety of active ingredients, such as phenylethanol glycosides (such as echinacoside, verbascoside), iridoids, polysaccharides, amino acids and betaine, etc., which play an important role in pharmacological effects. Cistanche deserticola water extract has a variety of effects such as tonifying the kidney and yang, moistening the intestines and relieving constipation, enhancing immunity, and delaying aging. Especially when Cistanche deserticola water extract is used in health foods, the main active ingredients include phenylethanol glycoside compounds, among which the most notable are echinacoside and verbascoside, which give Cistanche deserticola water extract a variety of health effects.

[0004] More specifically, echinacea has neuroprotective, bone-protective, anti-injury, and liver-protective effects. It can reverse and protect dopaminergic neuron damage induced by various factors, and may be used to treat neurodegeneration such as Parkinson's and Alzheimer's diseases, and prevent and treat ischemic diseases of the brain. As one of the main active ingredients of Cistanche deserticola, echinacea glycoside occupies an important position in the water extract of Cistanche deserticola; verbascoside helps to nourish the kidney and strengthen yang, prevent and relieve sexual dysfunction, increase testosterone, quickly stimulate sperm production and maintain vitality, thereby improving human sexual function. In addition, it also has multiple physiological effects such as anti-inflammatory, immune enhancement, anti-hypoxia, free radical scavenging, DNA base repair, and treatment of liver fibrosis. It is also an important active ingredient in the water extract of Cistanche deserticola.

[0005] Conventional Cistanche deserticola water extract is prepared by water extraction of fresh and dried Cistanche deserticola slices. However, the extraction rates of echinacoside and verbascoside in the Cistanche deserticola water extract are low. It is necessary to further improve the extraction rates of echinacoside and verbascoside in the water extract preparation process, thereby increasing the contents of active ingredients, especially echinacoside and verbascoside, in the Cistanche deserticola water extract. Summary of the invention

[0006] In order to further improve the extraction rate of echinacoside and verbascoside, thereby increasing the content of active ingredients in the Cistanche deserticola water extract, especially echinacoside and verbascoside, the present application provides a Cistanche deserticola water extract and a preparation method thereof.

[0007] In a first aspect, the present application provides a method for preparing an aqueous extract of Cistanche deserticola, using the following technical solution: A method for preparing a Cistanche deserticola water extract comprises the following steps: S1. Take dried Cistanche deserticola, crush and sieve to obtain Cistanche deserticola powder; S2, soaking the Cistanche deserticola powder in the soaking liquid, applying a high pressure condition of 3.8-4.5 MPa, treating for 15-25 minutes, first releasing the pressure to 1.2-1.7 MPa, soaking for 10-20 minutes, and then releasing the pressure to normal pressure to obtain a pre-treated mixture; S3, adding water to the pre-treated mixture for water extraction to obtain a Cistanche deserticola crude extract, and then concentrating and drying under reduced pressure to obtain a Cistanche deserticola water extract; The soaking liquid in step S2 is a soaking liquid prepared by mixing a hydroxyl-containing ionic liquid, water and ethylene glycol carbonate in a mass ratio of 1:(8-10):(1-2).

[0008] By adopting the above technical scheme, in the present application, the Herba Cistanches is firstly soaked in the soaking liquid, and high pressure is applied at the same time. The pretreatment under high pressure reduces the density of the cell wall, making the active ingredients more easily leached out by water, thereby increasing the release rate of the active ingredients. In the present application, high pressure soaking is firstly adopted, and then the pressure is released in stages to reduce the damage to the Herba Cistanches. Moreover, the concentration difference inside and outside the cell under different pressures drives the migration of solutes, which is more conducive to the diffusion of active substances in the cell into the soaking liquid. In addition, the soaking liquid in the present application is a mixture of hydroxyl ionic liquid, water and ethylene glycol carbonate. Since echinacoside and verbascoside molecules contain a large number of hydroxyl groups and have strong polarity, the present application In the soaking liquid, a hydroxyl-containing ionic liquid is added. The hydroxyl functional groups in the ionic liquid form intermolecular forces such as hydrogen bonds with the active substances of echinacoside and verbascoside, which helps to improve their solubility in water. More importantly, ethylene glycol carbonate is added in the present application. Ethylene glycol carbonate is soluble in water and is acidic after being dissolved in water. As a polarity regulator and acid-base regulator, it can change the ionization state of the hydroxyl active substance by adjusting the pH value of the solution, thereby affecting its solubility in water, and ultimately significantly improving the dissolution efficiency of echinacoside and verbascoside in water. Combined with subsequent water extraction treatment, the content of the active ingredients of echinacoside and verbascoside in the final Cistanche deserticola water extract is significantly increased.

[0009] Optionally, the hydroxyl-containing ionic liquid in the soaking solution is selected from one or more of 1-hydroxyethyl-3-methylimidazole chloride, 1-hydroxyethyl-3-methylimidazole tetrafluoroborate, 2-hydroxy-N,N,N,-trimethylethylamine chloride, and 2-hydroxy-N,N,N-trimethylethylamine tetrafluoroborate ionic liquids.

[0010] By adopting the above technical scheme, the above ionic liquid is selected in the present application as an ionic liquid containing hydroxyl groups and soluble in water, whose hydroxyl functional groups increase hydrophilicity and polarity, and promote the dissolution and release of echinacoside and verbascoside active substances through interactions such as hydrogen bonds.

[0011] Optionally, the hydroxyl-containing ionic liquid in the soaking solution includes 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate and 2-hydroxy-N,N,N,-trimethylethylamine chloride in a mass ratio of 1:(0.5-0.7).

[0012] By adopting the above technical scheme, selecting the compound of the above specific substances, introducing the fluorine group in 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate, and because the fluorine atom has a large electronegativity and a small atomic radius, the present application selects a combination of two ionic liquids with different anions and cations, namely 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate and 2-hydroxy-N,N,N,-trimethylethylamine chloride, and then adjusting the viscosity with fluorine atoms, so that the hydroxyl-containing ionic liquid has low viscosity and better fluidity, can effectively penetrate into the Cistanche deserticola powder, promote the dissolution of the effective ingredients in water, and the low-viscosity ionic liquid can also reduce the mass transfer resistance in the extraction process and improve the extraction efficiency.

[0013] Optionally, 2-hydroxy-N,N,N,-trimethylethylamine chloride is subjected to acidification modification and post-treatment, and the specific operation is: 2-hydroxy-N,N,N,-trimethylethylamine chloride and ammonium lactate are mixed in an aqueous solution, heated to 75-85° C. and stirred for reaction for 80-100 minutes, and then the solvent water is evaporated and cooled for crystallization to obtain an acid-modified ionic liquid.

[0014] By adopting the above technical scheme, in the present application, 2-hydroxy-N,N,N,-trimethylethylamine chloride ([HOCH2CH2N(CH3)3]Cl) is reacted with ammonium lactate in an aqueous solution, so that chloride ions are replaced by lactate ions to generate lactate-substituted ionic liquid [HOCH2CH2N(CH3)3]CH3CHOHCOO. Lactate has a stronger affinity for the hydroxyl groups in the active substances of echinacoside and verbascoside, which further helps to increase the content of echinacoside and verbascoside in the final Cistanche deserticola water extract.

[0015] Optionally, when 2-hydroxy-N,N,N,-trimethylethylamine chloride is acidified for modification, the added mass ratio of 2-hydroxy-N,N,N,-trimethylethylamine chloride to ammonium lactate is 1:(0.3-0.5).

[0016] Optionally, the specific operation of the water extraction treatment in step S3 is: adding water to the pre-treated mixture, first soaking it at room temperature and pressure for 30-40 minutes, then heating it to 65-75°C for 80-100 minutes, stirring it every 15 minutes, to obtain a crude Cistanche extract.

[0017] By adopting the above technical solution and the above water extraction method, the active ingredients in Cistanche deserticola can be effectively extracted while maintaining its biological activity.

[0018] Optionally, during the water extraction process in step S3, the amount of water added is 8-10 times the mass of the Cistanche deserticola powder.

[0019] Optionally, in step S3, the obtained Cistanche deserticola extract is first concentrated under reduced pressure at 45-55° C. by a rotary evaporator to 1 / 3 of the original volume, and then spray-dried to obtain the Cistanche deserticola water extract.

[0020] By adopting the above technical solution, the above subsequent treatment further improves the extraction efficiency and the retention rate of active ingredients, while making the product easier to store and use.

[0021] In a second aspect, the present application provides a Cistanche deserticola aqueous extract, using the following technical solution: A Cistanche deserticola water extract is prepared by the preparation method.

[0022] By adopting the above technical scheme, the content of echinacoside and verbascoside active ingredients in the Cistanche deserticola water extract prepared by the preparation method provided in the present application is higher, which is more conducive to the application and promotion of the Cistanche deserticola water extract in the fields of health care, anti-inflammatory and antioxidant medicines.

[0023] In summary, this application has the following beneficial effects: 1. In the present application, the herb Cistanche deserticola is first soaked in a soaking solution, and high pressure conditions are applied at the same time. The pretreatment under high pressure conditions reduces the density of the cell wall, making the active ingredients more easily leached out by water, thereby increasing the release rate of the active ingredients. In the present application, high pressure conditions are first used for soaking, and then the pressure is released in stages to reduce damage to the herb Cistanche deserticola. The concentration difference inside and outside the cell under different pressures drives the migration of solutes, which is more conducive to the diffusion of active substances in the cell into the soaking solution, and is conducive to the dissolution of the active ingredients of echinacoside and verbascoside. 2. The soaking liquid in the present application is a mixture of hydroxyl-containing ionic liquid, water and ethylene glycol carbonate. Since echinacoside and verbascoside molecules contain a large number of hydroxyl groups and have strong polarity, a hydroxyl-containing ionic liquid is added to the soaking liquid in the present application. The hydroxyl functional groups in the ionic liquid form hydrogen bonds and other intermolecular forces with the active substances of echinacoside and verbascoside, which helps to improve their solubility in water. More importantly, ethylene glycol carbonate is added to the present application. Ethylene glycol carbonate is soluble in water and is acidic after being dissolved in water. As a polarity regulator and acid-base regulator, it can change the ionization state of the hydroxyl active substance by adjusting the pH value of the solution, thereby affecting its solubility in water, and ultimately significantly improving the dissolution efficiency of echinacoside and verbascoside in water. Combined with subsequent water extraction treatment, the content of echinacoside and verbascoside active ingredients in the final Cistanche deserticola water extract is significantly increased. DETAILED DESCRIPTION

[0024] The present application is further described in detail below in conjunction with the examples. It is particularly noted that if no specific conditions are specified in the following examples, the experiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0025] Example 1 A method for preparing a Cistanche deserticola water extract comprises the following steps: S1. Taking 1 kg of Cistanche deserticola as the processing basis, taking dried Cistanche deserticola, crushing it through a 60-mesh sieve to obtain Cistanche deserticola powder; S2, soaking the Cistanche deserticola powder in the soaking solution, applying a high pressure condition of 4 MPa, soaking for 20 minutes, first releasing the pressure to 1.5 MPa, and then releasing the pressure to normal pressure after soaking for 15 minutes, to obtain a pre-treated mixture; The soaking liquid in step S2 is a soaking liquid prepared by mixing a hydroxyl-containing ionic liquid, water and ethylene glycol carbonate in a mass ratio of 1:9:1.5, and the hydroxyl-containing ionic liquid is a mixture of 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate and 2-hydroxy-N,N,N,-trimethylethylamine chloride in a mass ratio of 1:0.6; S3, adding water to the pre-treated mixture for water extraction to obtain a Cistanche deserticola crude extract, specifically: adding water to the pre-treated mixture, first soaking at room temperature and pressure for 30-40 minutes, then heating to 70°C for 90 minutes, stirring once every 15 minutes, to obtain a Cistanche deserticola crude extract, wherein the amount of water added is 9 times the mass of the Cistanche deserticola powder; Then the prepared Cistanche deserticola extract was first concentrated to 1 / 3 of the original volume under reduced pressure at 50° C. by a rotary evaporator, and then spray-dried to obtain the Cistanche deserticola water extract.

[0026] Example 2 A method for preparing a Cistanche deserticola water extract comprises the following steps: S1. Taking 1 kg of Cistanche deserticola as the processing basis, taking dried Cistanche deserticola, crushing it through a 60-mesh sieve to obtain Cistanche deserticola powder; S2, soaking the Cistanche deserticola powder in the soaking solution, applying a high pressure condition of 3.8 MPa, soaking for 25 minutes, first releasing the pressure to 1.2 MPa, and then releasing the pressure to normal pressure after soaking for 20 minutes, to obtain a pre-treated mixture; The soaking liquid in step S2 is a soaking liquid prepared by mixing a hydroxyl-containing ionic liquid, water and ethylene glycol carbonate in a mass ratio of 1:8:1, and the hydroxyl-containing ionic liquid is a mixture of 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate and 2-hydroxy-N,N,N,-trimethylethylamine chloride in a mass ratio of 1:0.5; S3, adding water to the pre-treated mixture for water extraction to obtain a Cistanche deserticola crude extract, the specific operation is: adding water to the pre-treated mixture, first soaking at room temperature and pressure for 30 minutes, then heating to 65° C. for 100 minutes, stirring once every 15 minutes during the process, to obtain a Cistanche deserticola crude extract, wherein the amount of water added is 8 times the mass of the Cistanche deserticola powder; Then the prepared Cistanche deserticola extract is first concentrated to 1 / 3 of the original volume by a rotary evaporator at 45°C under reduced pressure, and then spray-dried to obtain the Cistanche deserticola water extract.

[0027] Example 3 A method for preparing a Cistanche deserticola water extract comprises the following steps: S1. Taking 1 kg of Cistanche deserticola as the processing basis, taking dried Cistanche deserticola, crushing it through a 60-mesh sieve to obtain Cistanche deserticola powder; S2, soaking the Cistanche deserticola powder in the soaking solution, applying a high pressure condition of 4.5 MPa, soaking for 15 minutes, first releasing the pressure to 1.7 MPa, and then releasing the pressure to normal pressure after soaking for 10 minutes, to obtain a pre-treated mixture; The soaking liquid in step S2 is a soaking liquid prepared by mixing a hydroxyl-containing ionic liquid, water and ethylene glycol carbonate in a mass ratio of 1:10:2, and the hydroxyl-containing ionic liquid is a mixture of 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate and 2-hydroxy-N,N,N,-trimethylethylamine chloride in a mass ratio of 1:0.7; S3, adding water to the pre-treated mixture for water extraction to obtain a Cistanche deserticola crude extract, specifically: adding water to the pre-treated mixture, first soaking at room temperature and pressure for 40 minutes, then heating to 75°C for 80 minutes, stirring once every 15 minutes, to obtain a Cistanche deserticola crude extract, wherein the amount of water added is 10 times the mass of the Cistanche deserticola powder; Then the prepared Cistanche deserticola extract was first concentrated to 1 / 3 of the original volume by a rotary evaporator at 55° C. under reduced pressure, and then spray-dried to obtain the Cistanche deserticola water extract.

[0028] Example 4 A method for preparing an aqueous extract of Cistanche deserticola is carried out according to the method in Example 1, except that in step S2, the 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate in the hydroxyl ionic liquid contained in the soaking solution is replaced by an equal amount of 2-hydroxy-N,N,N-trimethylethylamine tetrafluoroborate.

[0029] Example 5 A method for preparing an aqueous extract of Cistanche deserticola is carried out according to the method in Example 1, except that in step S2, an equal amount of 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate in the hydroxyl ionic liquid contained in the soaking solution is replaced by 2-hydroxy-N,N,N,-trimethylethylamine chloride.

[0030] Example 6 A method for preparing a Cistanche deserticola water extract is carried out according to the method in Example 1, except that the hydroxyl ion liquid contained in the soaking liquid in step S2 is 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate.

[0031] Example 7 A method for preparing an aqueous extract of Cistanche deserticola is carried out according to the method in Example 1, except that the hydroxyl ion liquid in the soaking liquid in step S2 is 2-hydroxy-N,N,N,-trimethylethylamine chloride.

[0032] Example 8 A method for preparing an aqueous extract of Cistanche deserticola is carried out according to the method in Example 1, except that the 2-hydroxy-N,N,N,-trimethylethylamine chloride in the hydroxy ionic liquid in the soaking solution in step S2 is modified and then added: 2-Hydroxy-N,N,N,-trimethylethylamine chloride and ammonium lactate are mixed in a mass ratio of 1:0.4, and then added into water for mixing. The amount of water added is 5 times the mass of 2-hydroxy-N,N,N,-trimethylethylamine chloride. The mixture is heated to 80°C and stirred for reaction for 90 minutes. The solvent water is then evaporated and cooled for crystallization to obtain an acidic modified ionic liquid, which is then mixed with 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate and added.

[0033] Example 9 A method for preparing an aqueous extract of Cistanche deserticola is carried out according to the method in Example 1, except that the 2-hydroxy-N,N,N,-trimethylethylamine chloride in the hydroxy ionic liquid in the soaking solution in step S2 is modified and then added: 2-Hydroxy-N,N,N,-trimethylethylamine chloride and ammonium lactate are mixed in a mass ratio of 1:0.3, and then added into water for mixing. The amount of water added is 4 times the mass of 2-hydroxy-N,N,N,-trimethylethylamine chloride. The mixture is heated to 75°C and stirred for 100 minutes. The solvent water is then evaporated and cooled for crystallization to obtain an acidic modified ionic liquid, which is then mixed with 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate and added.

[0034] Example 10 A method for preparing an aqueous extract of Cistanche deserticola is carried out according to the method in Example 1, except that the 2-hydroxy-N,N,N,-trimethylethylamine chloride in the hydroxy ionic liquid in the soaking solution in step S2 is modified and then added: 2-Hydroxy-N,N,N,-trimethylethylamine chloride and ammonium lactate are mixed in a mass ratio of 1:0.5, and then added into water for mixing. The amount of water added is 6 times the mass of 2-hydroxy-N,N,N,-trimethylethylamine chloride. The mixture is heated to 85°C and stirred for reaction for 80 minutes. The solvent water is then evaporated and cooled for crystallization to obtain an acidic modified ionic liquid, which is then mixed with 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate and added.

[0035] Comparative Example 1 A method for preparing a Cistanche deserticola water extract is carried out according to the method in Example 1, except that, in step S2, high pressure conditions are not applied during immersion in the immersion solution, and a pre-treated mixture is obtained after immersion for 35 minutes under normal pressure.

[0036] Comparative Example 2 A method for preparing a Cistanche deserticola water extract is carried out according to the method in Example 1, except that no ethylene glycol carbonate is added to the soaking solution in step S2.

[0037] Comparative Example 3 A method for preparing a Cistanche deserticola water extract is carried out according to the method in Example 1, except that in step S2, an equal amount of ethylene glycol carbonate in the soaking solution is replaced by methanol.

[0038] Comparative Example 4 A method for preparing a Cistanche deserticola water extract is carried out according to the method in Example 1, except that in step S2, the hydroxyl ion liquid in the soaking solution is replaced with 1-dodecyl-3-methylimidazole tetrafluoroborate in equal amounts.

[0039] Comparative Example 5 A method for preparing a Cistanche deserticola water extract is carried out according to the method in Example 1, except that the Cistanche deserticola powder obtained in step S1 is directly subjected to the water extraction treatment in step S3 without being subjected to step S2.

[0040] Performance Testing The same batch of Cistanche tubulosa was taken and operated according to the methods in the above embodiments and comparative examples to obtain Cistanche deserticola water extracts. The yields of echinacoside and verbascoside in the Cistanche deserticola water extracts obtained by the methods provided in the embodiments and comparative examples of the present application (i.e., the amounts of echinacoside and verbascoside extracted per gram of raw material) were statistically analyzed, and the test results are shown in Table 1 below.

[0041] Table 1: In addition, when the traditional water extraction method is used to extract Cistanche deserticola in Comparative Example 5, it can be seen that the yield of echinacoside is only 5.32 mg / g, and the yield of verbascoside is only 2.45 mg / g. The method provided in the embodiment of the present application pre-treats Cistanche deserticola and then extracts it with water, which significantly improves the extraction rate of echinacoside and verbascoside, thereby increasing their content in the Cistanche deserticola water extract. Referring to the test results of Example 1 and Examples 4 and 5, it can be seen that when the ionic liquid in Example 5 does not contain fluorine element, the final yield of echinacoside and verbascoside is significantly reduced, and when the hydroxyl ionic liquid in Example 4 is a fluorine-containing hydroxyl ionic liquid, the yield is higher. Combined with the test results of Examples 6 and 7, when a single ionic liquid is selected for immersion treatment, the final extracted echinacoside and verbascoside are significantly reduced. The selection of different ionic liquids and the combination of different anions and cations will affect the viscosity of the ionic liquid, thereby affecting the final extraction effect; combined with the test results of Examples 8-10, 2-hydroxy-N,N,N,-trimethylethylamine chloride is added after being modified by lactic acid anion replacement, and the extraction effect of echinacoside and verbascoside is significantly improved, and the final yield is significantly improved.

[0042] Combining the test results of Example 1 and Comparative Example 1, when high pressure conditions are not applied in step S2 of Comparative Example 1, the final yield of echinacoside and verbascoside is significantly reduced, and the high pressure external conditions are more conducive to the release and dissolution of the effective ingredients of echinacoside and verbascoside in Cistanche deserticola; referring to the test results of Comparative Examples 2 and 3, when ethylene glycol carbonate is not added to the soaking solution in Comparative Example 3 but methanol is added, it can be seen that the yield of echinacoside and verbascoside changes less than that of Comparative Example 2, which is much lower than the test results in the embodiment. Referring to Comparative Example 4, when the ionic liquid uses an ordinary ionic liquid that does not contain hydroxyl groups, the yield of echinacoside and verbascoside is lower.

[0043] In summary, the yield of echinacoside and verbascoside in the water extract of Cistanche deserticola in this application is significantly higher than that of the traditional method, which not only improves the extraction efficiency, but also provides high-quality raw materials for the health food industry, and has significant health effects of enhancing immunity, anti-fatigue and anti-aging.

[0044] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing a Cistanche deserticola aqueous extract, characterized in that: The following steps are involved: S1. Take dried Cistanche deserticola, crush and sieve to obtain Cistanche deserticola powder; S2, soaking the Cistanche deserticola powder in the soaking liquid, applying a high pressure condition of 3.8-4.5 MPa, treating for 15-25 minutes, first releasing the pressure to 1.2-1.7 MPa, soaking for 10-20 minutes, and then releasing the pressure to normal pressure to obtain a pre-treated mixture; S3, adding a solvent to the pre-treated mixture for water extraction to obtain a Cistanche deserticola crude extract, and then concentrating and drying under reduced pressure to obtain a Cistanche deserticola water extract; The soaking liquid in step S2 is a soaking liquid prepared by mixing a hydroxyl-containing ionic liquid, water and ethylene glycol carbonate in a mass ratio of 1:(8-10):(1-2).

2. The method for preparing the Cistanche deserticola aqueous extract according to claim 1, characterized in that: The hydroxyl-containing ionic liquid in the soaking solution is selected from one or more of 1-hydroxyethyl-3-methylimidazole chloride, 1-hydroxyethyl-3-methylimidazole tetrafluoroborate, 2-hydroxy-N,N,N,-trimethylethylamine chloride, and 2-hydroxy-N,N,N-trimethylethylamine tetrafluoroborate ionic liquids.

3. The method for preparing the Cistanche deserticola aqueous extract according to claim 1, characterized in that: The hydroxyl ionic liquid in the soaking solution comprises 1-hydroxyethyl-3-methylimidazolium tetrafluoroborate and 2-hydroxy-N,N,N,-trimethylethylamine chloride in a mass ratio of 1:(0.5-0.7).

4. The method for preparing the Cistanche deserticola aqueous extract according to claim 3, characterized in that: 2-Hydroxy-N,N,N,-trimethylethylamine chloride is treated after acidification modification, and the specific operation is as follows: The 2-hydroxy-N,N,N,-trimethylethylamine chloride and ammonium lactate are mixed in an aqueous solution, heated to 75-85°C and stirred for reaction for 80-100 minutes, and then the solvent water is evaporated and cooled for crystallization to obtain an acidic modified ionic liquid.

5. The method for preparing the Cistanche deserticola aqueous extract according to claim 4, characterized in that: When 2-hydroxy-N,N,N,-trimethylethylamine chloride is acidified and modified, the added mass ratio of 2-hydroxy-N,N,N,-trimethylethylamine chloride to ammonium lactate is 1:(0.3-0.5).

6. The method for preparing the Cistanche deserticola aqueous extract according to claim 1, characterized in that: The specific operation of the water extraction treatment in step S3 is: adding water to the pre-treated mixture, first soaking it at room temperature and pressure for 30-40 minutes, then heating it to 65-75°C for 80-100 minutes, stirring it every 15 minutes, to obtain a crude Cistanche extract.

7. The method for preparing the Cistanche deserticola aqueous extract according to claim 6, characterized in that: In the water extraction process of step S3, the amount of water added is 8-10 times the mass of the Cistanche deserticola powder.

8. The method for preparing the Cistanche deserticola aqueous extract according to claim 1, characterized in that: In step S3, the obtained Cistanche deserticola extract is first concentrated to 1 / 3 of the original volume under reduced pressure at 45-55° C. by a rotary evaporator, and then spray-dried to obtain the Cistanche deserticola water extract.

9. The Cistanche deserticola aqueous extract obtained by the preparation method according to any one of claims 1 to 8.

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