Trichosanthin sesquiterpene CNA as well as preparation method and application thereof

Abstract

The invention discloses a coccidoxane sesquiterpene CNA as well as a preparation method and application thereof, and belongs to the field of traditional Chinese medicine preparation. According to the present invention, cold soaking, silica gel and gel column chromatography are adopted to separate and extract the cocculin type sesquiterpene CNA compound represented by a formula I from coriaria sinica linn; the CNA compound has a novel cis-hydrogenated indene core structure, contains nine continuous chiral centers, has the characteristic of a highly crowded polycyclic skeleton, and has good biological activity. Cell experiments show that the coccidoxane sesquiterpene CNA can inhibit signal transduction of GABAB receptors in endogenous and exogenous systems, and can be used for preparing drugs for treating or preventing nervous system related diseases. A new direction is opened up for developing novel GABAB receptor antagonists or modulators, exploring GABA receptor related therapeutic targets and developing nervous system disease drugs.

Description

Technical Field

[0001] The invention relates to a tetrandane-type sesquiterpene CNA, a preparation method and an application thereof, and belongs to the field of traditional Chinese medicine pharmacy. Background Art

[0002] Neurological diseases refer to diseases that affect the central nervous system, such as the brain and spinal cord, or the peripheral nervous system. These diseases may be caused by genetics, degenerative processes, trauma, infection, or other factors. Neurological diseases are one of the important causes of disability and death worldwide. There are many types of neurological diseases, including common depression and anxiety, epilepsy, schizophrenia, Alzheimer's disease, Parkinson's disease, stroke, multiple sclerosis (MS), and less common amyotrophic lateral sclerosis (ALS), Huntington's disease, etc. With the aging of the population, especially in developed countries and some developing countries, the incidence of diseases related to neurodegenerative diseases (such as Alzheimer's disease and Parkinson's disease) has increased significantly. The development of drugs for neurological diseases is an important direction in the global biomedical field, but it also faces great challenges. Due to the complexity of neurological diseases, individual differences and the existence of the blood-brain barrier (BBB), the failure rate of drug research and development is high. The current main neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, are mainly treated with acetylcholinesterase inhibitors, such as donepezil and galantamine, which enhance cholinergic transmission and improve cognitive function. NDA receptor antagonists, such as memantine, can reduce glutamate toxicity. Parkinson's disease (PD) treatment drugs mainly include: levodopa (L-DOPA), dopamine agonists such as pramipexole, ropinirole, monoamine oxidase B inhibitors (MAO-B inhibitors) such as selegiline. Epilepsy treatment drugs include: regulating sodium channels, calcium channels, γ-aminobutyric acid (GABA) effects, etc. Drugs for the treatment of depression are mainly selective serotonin reuptake inhibitors such as sertraline. Benzodiazepines and 5-HT1A receptor agonists are commonly used to treat anxiety disorders. Dopamine D2 receptor antagonists, such as clozapine, are mainly used to treat schizophrenia, and other new drugs targeting glutamate and brain network functions are under development.

[0003] GABA B The receptor (γ-aminobutyric acid type B receptor) is a metabotropic G protein-coupled receptor (GPCR) responsible for mediating inhibitory neurotransmission. As an important member of the GABA receptor family, its main ligand is γ-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the brain. GABA B Their widespread distribution in the brain and involvement in multiple signaling pathways suggest that they are closely associated with a variety of psychiatric and neurological diseases, which often involve GABA B Changes in receptor function, including overactivation or decreased function. GABA BGABA receptors are widely distributed in the central nervous system and play a key role in regulating neural activity. B GABA receptors have become an important drug target in the development of drugs related to neurological diseases. B Receptor-related neurological diseases include epilepsy, depression and anxiety, chronic pain, addiction and dependence, hypotension, muscle spasms and Alzheimer's disease. Therefore, the development of new GABA B Receptor antagonists or modulators have opened up new directions for exploring GABA receptor-related therapeutic targets and developing drugs for neurological diseases. Summary of the invention

[0004] In order to more effectively treat nervous system diseases, the present invention aims to provide a drug and a preparation method that can B The signaling of the receptor has an inhibitory effect, and the development of a new type of GABA B Receptor antagonist or modulator. Among them, the sesquiterpene CNA of the tertium oxaline type provided by the present invention has a structure as shown in Formula I:

[0005]

[0006] A method for preparing a tetrandrine-type sesquiterpene CNA comprises the following steps:

[0007] (1) grinding the dried Coriaria officinalis flowers, cold-immersing and extracting them with a mixed solution of ethanol and water to obtain an extract, and performing reduced pressure distillation and concentration on the extract to obtain an extract;

[0008] (2) The extract is distributed into water, first extracted with petroleum ether, and then the water-soluble part after extraction is extracted with ethyl acetate to obtain an ethyl acetate phase extract.

[0009] (3) Separating the ethyl acetate phase extract by normal silica gel chromatography, first using petroleum ether-acetone as the mobile phase for gradient elution to obtain fractions F1, F2, F3, F4, and F5, and then using dichloromethane-methanol as the mobile phase for gradient elution to obtain fractions F6, F7, and F8. All fractions are rotated, concentrated, and weighed in turn to obtain 8 polar fractions F1 to F8;

[0010] (4) F5 was subjected to normal silica gel column chromatography using dichloromethane-methanol as the mobile phase for gradient elution to obtain 9 fractions F5-1 to F5-9;

[0011] (5) The F5-5 fraction was subjected to normal silica gel column chromatography using chloroform-methanol as the mobile phase for gradient elution to obtain four fractions F5-5-1 to F5-5-4;

[0012] (6) The F5-5-2 segment was separated by gel column, eluted with chloroform-methanol, impurities were removed, and recrystallized in acetone to obtain the tertium oxadiane-type sesquiterpene CNA substance.

[0013] Preferably, in step (1), the solid-liquid ratio of Coriaria japonica is 0.44 kg / L, the volume ratio of ethanol to water is 95:5, the extraction time is 24 h, and the number of cold soaking extractions is 3 times.

[0014] Preferably, petroleum ether is used for extraction in step (2) to remove impurities with low polarity.

[0015] Preferably, in step (3), the volume ratio of petroleum ether to acetone is 50:1 to 1:1, and the volume ratio of dichloromethane to methanol is 10:1 to 1:1, wherein F5 is obtained by eluting with petroleum ether to acetone in a ratio of 6:1.

[0016] Preferably, the volume ratio of dichloromethane to methanol in step (4) is 70:1 to 3:1, wherein F5-5 is eluted with dichloromethane to methanol in a ratio of 8:1.

[0017] Preferably, the volume ratio of chloroform to methanol in step (5) is 8:1 to 2:1, wherein F5-5-2 is obtained by eluting with chloroform to methanol in a ratio of 8:1.

[0018] Preferably, the volume ratio of chloroform to methanol in step (6) is 10:1 to 3:1.

[0019] In an embodiment of the present invention, the tetrandhane-type sesquiterpene CNA is extracted and separated from Coriaria officinalis flowers.

[0020] The medicine of the present invention comprises a tetrandrine-type sesquiterpene CNA compound.

[0021] Preferably, the medicine includes tablets, capsules, pills, injections, sustained-release preparations, and controlled-release preparations, but is not limited thereto.

[0022] Preferably, the drug is a combination drug formed by combining tertium oxadiane-type sesquiterpene CNA and at least one pharmaceutically acceptable carrier.

[0023] Preferably, the carrier includes alumina, polylactic acid-polyvinyl alcohol copolymer, polyvinyl alcohol, chitosan, liposome, sodium alginate and the like.

[0024] Preferably, the combination drug is a drug consisting of tertium oxadiane-type sesquiterpene CNA and a pharmaceutically acceptable salt.

[0025] Preferably, pharmaceutically acceptable salts include: citric acid, maleic acid, fumaric acid, hydrochloric acid, sulfuric acid, phosphoric acid, lithium, sodium, potassium, calcium, magnesium, lysine.

[0026] The sesquiterpenoid CNA compound of the present invention has the effect of inhibiting GABA in endogenous and exogenous systems. B Receptor signaling.

[0027] The invention relates to the use of the cyclopentane-type sesquiterpene CNA compounds and cyclopentane-type sesquiterpene CNA drugs in the preparation of drugs for treating or preventing nervous system diseases, wherein the nervous system diseases include epilepsy, depression, anxiety, schizophrenia, and neurodegenerative diseases.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention provides a novel sesquiterpene CNA of the oxadiazine type, which has a unique cis-hydroindene core structure, contains nine consecutive chiral centers, and has a highly crowded polycyclic skeleton feature.

[0030] (2) The tertium oxadiazine-type sesquiterpenoid CAN provided by the present invention is the first discovered natural GABA B Receptor antagonists can be used to prepare drugs for the treatment and prevention of nervous system diseases and have potential therapeutic significance for epilepsy, depression, anxiety, schizophrenia, neurodegenerative diseases, etc.

[0031] (3) The extraction process of the present invention is simple, and the confirmation of the structure of the sesquiterpenoid CNA of the tertium oxaline type and the cell experiment verification provide a basis for the development of new GABA B Receptor antagonists or modulators have opened up new directions for exploring GABA receptor-related therapeutic targets and developing drugs for neurological diseases. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a flow chart of the preparation method of the tertium oxadiane-type sesquiterpene CNA.

[0033] Figure 2 The tertium oxadiane type sesquiterpene CNA of the present invention 1 HNMR spectrum.

[0034] Figure 3 The tertium oxadiane type sesquiterpene CNA of the present invention 13 C NMR spectrum.

[0035] Figure 4 This is a single crystal X-ray diffraction pattern of the tertium oxadiane-type sesquiterpene CNA of the present invention.

[0036] Figure 5 It is a structural diagram of the tertium oxadiane-type sesquiterpene CNA of the present invention.

[0037] Figure 6 The compound CNA has an effect on endogenous GABA BThe inhibitory activity results of receptor activation are shown in the figure. The vertical axis is GABA in the endogenous system. B Receptor signaling Ca 2+ The horizontal axis is the concentration of compound CNA, in μM.

[0038] Figure 7 Compound CNA can induce exogenous GABA under GABA stimulation. B Receptor-activated inhibitory activity diagram, with the ordinate being endogenous GABA in the system B Receptor signaling Ca 2+ conduction, the abscissa is the concentration of compound CNA, in μM, where the concentration of GABA agonist is 5 μM.

[0039] Figure 8 Compound CNA stimulates exogenous GABA under the stimulation of Baclofen B Receptor-activated inhibitory activity diagram, with the ordinate being endogenous GABA in the system B Receptor signaling Ca 2+ conduction, the abscissa is the dose of compound CNA, in μM, where the concentration of Baclofen agonist is 1 μM. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0041] Example 1

[0042] A method for preparing tertium oxadiazine type sesquiterpene CNA, such as Figure 1 As shown, the following steps are included:

[0043] (1) 11 kg of dried Coriaria japonica flowers were crushed and dissolved in a mixed solvent of ethanol and water in a volume ratio of 95:5 at a solid-liquid ratio of 0.44 kg / L, and cold-extracted for 3 times at room temperature. The combined extracts were subjected to reduced pressure distillation and concentrated to remove the organic solvent to obtain an extract.

[0044] (2) The extract was distributed in an aqueous solution, first extracted with petroleum ether for three times to remove impurities with low polarity, and the water-soluble portion after extraction was fully extracted with ethyl acetate for three times to obtain a total of 500.0 g of ethyl acetate phase extract.

[0045] (3) The ethyl acetate phase extract was separated by normal silica gel column chromatography, and first eluted with petroleum ether-acetone in a volume ratio of 50:1 to 1:1, wherein F1 was obtained by eluting with petroleum ether-acetone 50:1, F2 was obtained by eluting with petroleum ether-acetone 30:1, F3 was obtained by eluting with petroleum ether-acetone 15:1, F4 was obtained by eluting with petroleum ether-ethyl acetate 10:1, and F5 was obtained by eluting with petroleum ether-acetone 6:1; then F6 was obtained by eluting with dichloromethane-methanol 10:1, F7 was obtained by eluting with dichloromethane-methanol 5:1, and F8 was obtained by eluting with dichloromethane-methanol 1:1. All the eluted samples were collected, and then rotated, concentrated and weighed in turn to obtain 8 polarity fractions in total.

[0046] (4) 52.8 g of the fraction F5 was subjected to normal silica gel column chromatography and eluted with a mobile phase of dichloromethane-methanol in a volume ratio of 70:1 to 3:1. Among them, dichloromethane-methanol 60:1 was used to obtain F5-1, dichloromethane-methanol 35:1 was used to obtain F51-2, dichloromethane-methanol 20:1 was used to obtain F5-3, dichloromethane-methanol 15:1 was used to obtain F5-4, dichloromethane-methanol 10:1 was used to obtain F5-5, dichloromethane-methanol 7:1 was used to obtain F5-6, dichloromethane-methanol 5:1 was used to obtain F5-7, dichloromethane-methanol 4:1 was used to obtain F5-8, and dichloromethane-methanol 3:1 was used to obtain F5-9. A total of 9 polar fractions were obtained.

[0047] (5) 3.0 g of the fraction F5-5 was subjected to normal silica gel column chromatography and eluted with chloroform-methanol in a volume ratio of 8:1 to 2:1 as the mobile phase. Elution with chloroform-methanol in a ratio of 8:1 to 2:1 gave F5-5-1, elution with chloroform-methanol in a ratio of 6:1 to give F5-5-2, elution with chloroform-methanol in a ratio of 4:1 to give F5-5-3, and elution with chloroform-methanol in a ratio of 2:1 to give F5-5-4 to obtain four mixtures.

[0048] (6) 1.2 g of the fraction F5-5-2 was separated by a gel column, separated and impurized using chloroform-methanol at a volume ratio of 10:1 to 3:1, recrystallized in acetone, and dried to obtain 7.0 mg of a tertium oxadiane-type sesquiterpene CAN compound in the form of colorless needles.

[0049] Example 2

[0050] The CNA compounds of the tertium oxadiane type were analyzed by nuclear magnetic resonance. 1 H NMR and 13 C NMR Figure 2 and Figure 3 As shown, 1 H NMR (600MHz in methanol-d4) and 13The C NMR (150 MHz in methanol-d4) data and signal assignments are shown in Table 1.

[0051] Table 1 NMR data and signal attribution of tertium oxadiane-type sesquiterpenoid CNAs

[0052]

[0053]

[0054] The sesquiterpenoid CNA compounds separated and extracted in Example 1 were analyzed by mass spectrometry (MS) and high-resolution mass spectrometry (HR-ESI-MS). The molecular ion peaks [M+Na] of the sesquiterpenoid CNA compounds were + m / z: 335.1111, calculated value is 335.1101. Combined with the analysis of NMR spectrum data, the molecular formula of the sesquiterpene CNA compound of the oxadiazine type was determined to be C 15 H 20 O7. The stereo configuration of the tertium oxadiazole-type sesquiterpenoid CNA was determined by x-single crystal diffraction analysis of the tertium oxadiazole-type sesquiterpenoid CAN compound, such as Figure 4 shown.

[0055] The crystal structure of the sesquiterpenoid CNA separated and extracted in Example 1 was further determined by comprehensive structural analysis such as NMR spectroscopy analysis, mass spectrometry (MS), high resolution mass spectrometry (HR-ESI-MS), and x-single crystal diffraction analysis. Figure 5 shown.

[0056] Effect example

[0057] Tetrandane-type sesquiterpenoids CAN inhibit GABA B Receptor activity verification includes the following specific steps:

[0058] 1. Culture of primary mouse cerebellar gynecocytes (CGNs)

[0059] One-week-old Balb / c mice were provided by Kunming Medical University. After the mice were euthanized, their cerebellum tissues were dissected, and the tissues were gently dissociated using a fire-polished Pasteur pipette, filtered through a cell strainer, and inoculated into a culture dish pre-coated with poly-L-ornithine (MAKLIN). Cell culture was performed in DMEM medium with 10% Hepes buffer and 10% double antibody added in advance, and then 10% heat-inactivated fetal bovine serum was added. After 5 days of culture, the cell density reached 90%.

[0060] 2. HEK293T cell culture

[0061] (1) Cell screening model: HepG2.2.15 cells were purchased from Guangzhou Saiku Biotechnology, subcultured by our laboratory, and stored in liquid nitrogen and a -80°C freezer.

[0062] (2) Culture medium: Add 10% double antibody and 10% Hepes buffer to 500 mL of DMEM culture medium.

[0063] (3) Cell recovery: Before the experiment, prepare complete culture medium in a clean bench and store it in a 4°C refrigerator for later use. The complete culture medium consists of 90% culture medium + 10% FBS. Shake it up and down to mix it thoroughly and heat it in a 37°C water bath. Take 5 mL of the warmed complete culture medium and put it in a T25 culture flask for later use. At this time, take out a frozen HEK293T cell from the liquid nitrogen tank and quickly put it in a 37°C water bath. Keep shaking gently. After it is completely thawed, inoculate the cell suspension into a T25 culture flask containing 5 mL of complete culture medium. The cells will adhere to the wall and grow in about 48 hours.

[0064] (4) Cell passaging: When the cell growth density reaches 90%, remove the cells from the incubator, discard the original culture medium, add 2 mL of preheated PBS each time, wash three times, then add 1 mL of trypsin, gently shake to allow all cells to fully contact, aspirate the trypsin, put the cells into the incubator for digestion for 3 minutes, and then examine under a microscope. When obvious changes in cell morphology are observed, add 2 mL of complete culture medium to terminate digestion, blow off the cells, transfer them to a 5 mL EP tube, and centrifuge at 1000 rpm for 3 minutes. After discarding the supernatant, add 1 mL of culture medium and blow evenly. Inoculate 300 μL of single-cell suspension in each culture dish, add 5 mL of culture medium, blow evenly, and put it into the incubator.

[0065] (5) Cell freezing: Take out cells (F3 / F4) with good growth status from the incubator, discard the original culture medium, add 2mL of fetal bovine serum PBS, wash 3 times, then add 1mL of trypsin to digest the cells, put them in the incubator for digestion for 3min, and then check under a microscope. Add 2mL of complete culture medium to terminate the digestion, blow down the cells, transfer them to an eppendorf tube, centrifuge at 1000rpm for 3min, discard the supernatant, add 1mL of serum-free freezing solution, and write the time, cell generation, freezing solution, cell name and operator on the freezing tube. Then perform gradient cooling and freezing: 4℃ for 30min→-20℃ for 2h→-80℃ overnight, and put them in liquid nitrogen the next day.

[0066] 3. Plasmid transfection

[0067] HEK293T cells were cultured in DMEM medium containing 10% fetal bovine serum (FBS) and seeded in 6-well plates. When the cell density reached 70%-90%, the medium was replaced with serum-free medium without double antibody. The plasmids GABBR1 and GABBR2 were co-transfected into the cells using Lip3000 transfection reagent. After 6 hours, the medium was replaced with complete medium and cultured for another 24 hours.

[0068] 4. Fluo-4AM fluorescent probe detects GABA in endogenous and exogenous cells B Changes in calcium flux signals downstream of the receptor

[0069] (1) Drug preparation: The tertium oxadiane-type sesquiterpenoid CAN compound was dissolved in DMSO to prepare 50 mM, and diluted in a gradient ratio of 50, 25, 12.5, and 6.25 μM for administration, with 3 replicate wells set for each drug concentration.

[0070] (2) Cell seeding: CGNs cells in good growth stage were selected with a cell density of 1×10 5 Each well was inoculated with 100 μL of the solution and placed in an incubator for 24 h. The original culture medium was discarded and the cells were incubated with the prepared 2 μM Fluo-4AM fluorescent probe for 1 hour.

[0071] (3) Fluo-4AM fluorescent probe to detect calcium signals: After 24 hours of culture, the original culture medium was discarded, and the cells were incubated with the prepared 2μM Fluo-4AM fluorescent probe for 1 hour, the dye was removed, and the cells were washed twice with PBS. The pre-prepared CAN drug solution was added to each well and incubated for 1 hour. Exogenous cells were stimulated with agonists GABA (5μM) and Baclofen (1μM) for one hour, and then the fluorescence intensity data was measured using an inverted fluorescence microscope.

[0072] Fluorescence intensity data were quantified using ImageJ, and graphs and statistical analyses were performed using GraphPad Prism software, version 5.0, from GraphPad Software Inc. 50 Values ​​were calculated by nonlinear regression and three-parameter logistic equation.

[0073] The results of endogenous primary mouse cerebellar cell experiments showed Figure 6 It was shown that the compound CNA can inhibit GABA in the endogenous system B receptor signal transduction, and showed a certain dose dependence; through exogenous HEK293T cell experiments, the compound CNA can inhibit GABA in the exogenous system B Receptor signaling, such as Figure 7As shown, in exogenous HEK293T cells, compound CNA showed a certain dose dependence under the stimulation of GABA agonist; Figure 8 As shown in Figure 2, in exogenous HEK293T cells, compound CNA showed a certain dose-dependency under the stimulation of Baclofen agonist, and the IC of compound CNA under the stimulation of GABA and Baclofen agonist was calculated. 50 The values ​​are shown in Table 2 below.

[0074] Table 2 IC values ​​of compound CNA under stimulation of two agonists 50 value

[0075]

[0076] According to Table 2, the IC of positive drug CGP54626 under two agonist stimulations 50 Compared with the values, compound CNA showed a significant decrease in the activity of GABA under the stimulation of two agonists. B The inhibitory activity of the receptor is lower than that of positive drugs, but from the IC 50 The compound CAN can significantly inhibit the exogenous GABA under the stimulation of two agonists. B Receptor activation.

[0077] In summary, the above experiments have proved that the sesquiterpenoid CNA prepared by the present invention has an effect on the GABA in endogenous and exogenous systems. B The activation of GABA receptors has a significant inhibitory effect, affecting B Receptor signal transduction can therefore be used to prepare drugs for preventing or treating nervous system diseases.

[0078] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A sesquiterpene CNA of the tertium thunoid type, characterized in that: The structure of the tetrandane-type sesquiterpene CNA is shown in Formula I:

2. The tetrandane-type sesquiterpene CNA according to claim 1, characterized in that: The cypermethrin-type sesquiterpenoid CNA is extracted and separated from Coriaria officinalis flowers.

3. The method for preparing the tetrandane-type sesquiterpene CNA according to claim 1 or 2, characterized in that: The following steps are involved: (1) taking dried Coriaria officinalis flowers, crushing them, and then cold-immersing and extracting them with ethanol aqueous solution, combining the extracts and concentrating them by vacuum distillation to obtain an extract; (2) distributing the extract in an aqueous solution, first extracting with petroleum ether, and then extracting the water-soluble part with ethyl acetate to obtain an ethyl acetate phase extract; (3) The ethyl acetate phase extract was separated by normal silica gel column chromatography, and gradient elution was performed with petroleum ether-acetone as the mobile phase, and 5 fractions F1, F2, F3, F4, and F5 were collected; then gradient elution was performed with dichloromethane-methanol as the mobile phase, and 3 fractions F6, F7, and F8 were collected. All the fractions were rotated, concentrated, and weighed in turn, and a total of 8 polar fractions were obtained; (4) Fraction F5 was subjected to normal silica gel column chromatography with dichloromethane-methanol as the mobile phase for gradient elution, and nine fractions F5-1 to F5-9 were obtained; (5) Fraction F5-5 was subjected to normal silica gel column chromatography with chloroform-methanol as the mobile phase for gradient elution to obtain four fractions F5-5-1 to F5-5-4; (6) Fraction F5-5-2 was purified by gel column chromatography using a chloroform-methanol gradient elution and impurity removal, and then recrystallized in acetone to obtain a tertium oxadiane-type sesquiterpene CNA compound.

4. The method for preparing the tetrandane-type sesquiterpene CNA according to claim 3, characterized in that: In the step (1), the solid-liquid ratio of Coriaria japonica is 0.44 kg / L; and the volume ratio of ethanol to water is 95:

5.

5. The method for preparing the tetrandane-type sesquiterpene CNA according to claim 3, characterized in that: In the step (3), the gradient ratio of petroleum ether to acetone is 50:1 to 1:1; and the gradient ratio of dichloromethane to methanol is 10:1 to 1:

1.

6. The method for preparing the tetrandane-type sesquiterpene CNA according to claim 3, characterized in that: In the step (4), the gradient ratio of dichloromethane to methanol is 70:1 to 3:

1.

7. The method for preparing the tetrandane-type sesquiterpene CNA according to claim 3, characterized in that: The gradient ratio of chloroform to methanol in step (5) is 8:1 to 2:

1.

8. The method for preparing the tetrandane-type sesquiterpene CNA according to claim 3, characterized in that: The gradient ratio of chloroform to methanol in the purification step (6) is 10:1 to 3:

1.

9. Use of the tetrandhanoid sesquiterpene CNA according to claim 1 in the preparation of drugs for treating or preventing nervous system diseases, wherein the nervous system diseases include epilepsy, depression, anxiety, schizophrenia, and neurodegenerative diseases.

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