A sesquiterpene dimer compound, and a preparation method and application thereof

Abstract

The application discloses a sesquiterpene dimer and a preparation method and application thereof, and belongs to the technical field of natural compound extraction. According to the preparation method, dried sesquiterpene dimers are extracted by refluxing with 95% ethanol, and then petroleum ether and ethyl acetate are used for extraction to obtain an extract, which can be obtained by column chromatography and semi-preparative high performance liquid chromatography, so that the method is simple, time and labor are saved, and the yield is higher. The obtained sesquiterpene dimers have high anti-neuritis activity, and have important application prospects for developing new drugs for treating senile dementia.

Description

Technical Field

[0001] This invention relates to the field of natural compound extraction technology, specifically to sesquiterpene dimer compounds extracted from *Sarcandra glabra*, their preparation methods, and applications. Background Technology

[0002] Coralgrass ( Sarcandra glabra (Thunb.) Nakai is a species of coral belonging to the genus *Thunb.* in the family Chloranthaceae. Sarcandra *Sarcandra glabra*, a plant from which *Sarcandra glabra* (also known as *Sarcandra glabra*), a traditional Chinese medicine, originates, and the whole plant is used medicinally. It has the effects of clearing heat and cooling blood, promoting blood circulation and eliminating rashes, dispelling wind and unblocking meridians, and is used for rashes caused by blood heat, rheumatic pain, and traumatic injuries. *Sarcandra glabra* is abundant in my country. In existing traditional Chinese medicine preparations and folk remedies related to *Sarcandra glabra*, it is often used to treat sore throat, acute and chronic pharyngitis, and tonsillitis. Modern pharmacological studies have shown that *Sarcandra glabra* has multiple effects, including anti-inflammatory, antimalarial, antitumor, antibacterial, antioxidant, and neuroprotective properties. In Guizhou, it is known as "bone-setting tea" in traditional Chinese medicine and is widely used in folk medicine. Guizhou, as one of the main producing areas of *Sarcandra glabra*, may have unique karst topography and climate that induces the production of novel and more active secondary metabolites.

[0003] Recent domestic and international research reports indicate that plants in the Chloranthaceae family possess diverse chemical components and broad biological activities. Studies have found that plants such as *Chloranthus broadleaf*, *Chloranthus fimbriatus*, and *Sarcandra hainanensis* mainly contain sesquiterpenes, flavonoids, coumarins, and organic acids. These components endow the plants with a wide range of biological activities, including antimalarial, anti-inflammatory, antibacterial, antiviral, anti-ulcer, analgesic, antitumor, and neuroprotective effects. Among these, lindera sesquiterpenes and their dimers are hallmark components of Chloranthaceae plants. Recent studies have shown that these components exhibit excellent anti-inflammatory activity, particularly in inhibiting lipopolysaccharide-induced NO production in microglia. Therefore, to further explore new anti-inflammatory active substances from *Sarcandra hainanensis*, this application conducted in-depth research on the chemical components and anti-inflammatory mechanisms of *Sarcandra hainanensis*, isolating new sesquiterpene dimer compounds. Summary of the Invention

[0004] This invention proposes a sesquiterpene dimer compound, its preparation method, and its application, which not only solves the problem of complex preparation methods but also provides a foundation for the discovery of new anti-inflammatory drugs.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] In a first aspect, the present invention provides a novel sesquiterpene dimer extracted from *Sarcandra glabra*, the chemical structure of which is as follows:

[0007] .

[0008] Secondly, the present invention also discloses a method for preparing sesquiterpene dimers, comprising the following steps:

[0009] 1) After the grass coral is dried, it is crushed, extracted with organic solvent, and then extracted by hot reflux and concentrated under reduced pressure to recover the solvent, so as to obtain crude extract.

[0010] 2) The crude extract was suspended in water and extracted sequentially with organic solvents. The extraction solvents were then recovered to obtain the extract of Coral Gynostemma pentaphyllum.

[0011] 3) The extract of *Sarcandra glabra* from step 2) was eluted with a normal-phase silica gel gradient using dichloromethane / methanol at a volume ratio of 100:0 to 0:100. Thin-layer chromatography was then used to detect the fractions that showed fluorescence under UV light and / or the chromogenic fractions developed by 5% sulfuric acid ethanol, respectively, to obtain fractions Fr.1 to Fr.16.

[0012] 4) The Fr.16 from step 3) was subjected to gradient elution by MCI GEL CHP20P column chromatography with methanol / water at a volume ratio of 50:50~100:0. Thin-layer chromatography was then used to detect the fluorescence under UV light and / or the colorimetric fraction of 5% sulfuric acid ethanol, respectively, to obtain the Fr.16.1~Fr.16.12 fractions.

[0013] 5) Elute Fr.16.8 from step 4) with a normal-phase silica gel gradient using petroleum ether / ethyl acetate at a volume ratio of 8:1 to 1:1, and then detect the elution by thin-layer chromatography. Collect the components that fluoresce under UV light and / or the colorimetric components of 5% sulfuric acid ethanol to obtain the components Fr.16.8.1 to Fr.16.8.8, respectively.

[0014] 6) The Fr.16.8.6 from step 5) was subjected to Sephadex LH-20 column chromatography with dichloromethane / methanol at a volume ratio of 1:1 as the eluent, and then detected by thin-layer chromatography. The components that fluoresce under UV light and / or the colorimetric components of 5% sulfuric acid ethanol were collected sequentially to obtain the components Fr.16.8.6.1 to Fr.16.8.6.5, respectively.

[0015] 7) Fr.16.8.6.5 from step 6) was further purified by semi-preparative HPLC. Methanol / water with a volume ratio of 58:42 was selected as the mobile phase, and the chromatographic peak was collected at a retention time of 15 min to obtain the compound shown in formula (I).

[0016] Further, in step 1), the organic solvent is 95% ethanol, the volume of ethanol used is 3~5 L / kg based on the weight of the Coral Gum powder, and the reflux extraction is performed at least 3 times, with each extraction lasting 2 hours.

[0017] Further, the organic solvents mentioned in step 2) are petroleum ether and ethyl acetate, and the crude extract is extracted with petroleum ether and ethyl acetate 5-6 times each; the volume of water used for water suspension is 2-5 L / kg based on the weight of the crude extract; the volume ratio of petroleum ether and ethyl acetate to water is 1:1.

[0018] Furthermore, the elution conditions for silica gel column chromatography in step 3) are as follows: gradient elution is performed sequentially using a dichloromethane / methanol mixed solvent with volume ratios of 100:0, 100:1, 50:1, 25:1, 10:1, 5:1, 2:1, 1:1, and 0:100 as the eluent.

[0019] Further, in step 4), the elution conditions for MCI GEL CHP20P column chromatography are as follows: gradient elution is performed using methanol / water mixed solvents with volume ratios of 50:50, 60:40, 70:30, 80:20, 90:10, and 100:0.

[0020] Thirdly, the sesquiterpene dimer compounds extracted from *Sarcandra glabra* provided by this invention have significant anti-inflammatory activity and can exert anti-neuritis activity by downregulating the expression levels of COX-2, iNOS, and MYD88 proteins.

[0021] Fourthly, the sesquiterpene dimer compounds extracted from *Sarcandra glabra* provided by this invention have significant anti-inflammatory activity and can be used as anti-inflammatory drugs or for the preparation of anti-inflammatory drugs.

[0022] The beneficial effects of the sesquiterpene dimer compound, its preparation method, and its application are as follows:

[0023] This invention extracts sesquiterpene dimer compounds from *Sarcandra glabra* by reflux extraction with 95% ethanol, followed by extraction with petroleum ether and ethyl acetate to obtain an extract. The extract can be obtained by column chromatography and semi-preparative high-performance liquid chromatography. The method is simple, time-saving, labor-saving, and has a higher yield.

[0024] The sesquiterpene dimer compounds extracted from *Sarcandra glabra* are novel structural compounds that exert anti-neuroinflammatory effects by regulating the expression levels of COX-2, iNOS, and MYD88 proteins. They have the effect of inhibiting neuroinflammation and have important application prospects for the development of new drugs for the treatment of Alzheimer's disease. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 It is compound 1 1 H-NMR spectrum;

[0027] Figure 2 It is compound 1 13 C-NMR spectrum;

[0028] Figure 3 In the diagram, A is the HSQC spectrum of compound 1, and B is the HMBC spectrum of compound 1.

[0029] Figure 4 The middle is compound 1 of compound 1. 1 H- 1 H is the COSY spectrum, and B is the NOESY spectrum of compound 1;

[0030] Figure 5 It is the HRESIMS of compound 1;

[0031] Figure 6 This is the IR spectrum of compound 1;

[0032] Figure 7 This is the UV spectrum of compound 1;

[0033] Figure 8 This is the CD spectrum of compound 1;

[0034] Figure 9 This is a correlation diagram of COSY and HMBC for compound 1;

[0035] Figure 10 This is the NOESY correlation graph for compound 1;

[0036] Figure 11 The IC50 of compound 1 (20 µM) inhibiting LPS-induced NO production in BV-2 cells is [not specified]. 50 picture;

[0037] Figure 12 The effect of compound 1 on the LPS-induced NF-κB signaling pathway in BV-2 cells. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0039] A sesquiterpene dimer compound extracted from *Sarcandra glabra* has the chemical structural formula shown in formula (I):

[0040] .

[0041] Example 1

[0042] A method for preparing a sesquiterpene dimer includes the following steps:

[0043] (1) After drying the coral bark (85 kg), it was crushed and extracted three times by hot reflux with 95% ethanol (3×250 L) for 2 hours each time. The ethanol solvent was recovered by vacuum concentration to obtain crude extract.

[0044] (2) Add water to the crude extract and vortex, then extract with petroleum ether and ethyl acetate 5-6 times each, and recover the extraction solvent to obtain the petroleum ether extract of Coralgranatum (1.89 kg) and the ethyl acetate extract (3.62 kg).

[0045] (3) Select the ethyl acetate extract of *Sargassum fusiforme*, add it to 40-80 mesh silica gel, and then perform fractional chromatography on a 200-300 mesh normal silica gel column. Elute with a dichloromethane / methanol gradient. The gradient elution is as follows: first, elute with a 100:0 mixture of dichloromethane and methanol; second, elute with a 100:1 mixture of dichloromethane and methanol; third, elute with a 50:1 mixture of dichloromethane and methanol; and finally, elute with a 50:1 mixture of dichloromethane and methanol. The solution was eluted a fourth time with a methanol-dichloromethane mixture at a mass ratio of 20:1, a fifth time with a dichloromethane-methane mixture at a mass ratio of 10:1, a sixth time with a dichloromethane-methane mixture at a mass ratio of 5:1, a seventh time with a dichloromethane-methane mixture at a mass ratio of 2:1, an eighth time with a dichloromethane-methane mixture at a mass ratio of 1:1, and a ninth time with a dichloromethane-methane mixture at a mass ratio of 0:100.

[0046] The fractions obtained after elution nine times were analyzed by TLC and similar fractions were combined and divided into 16 fractions (Fr.1, Fr.2, Fr.3, Fr.4, Fr.5, Fr.6, Fr.7, Fr.8, Fr.9, Fr.10, Fr.11, Fr.12, Fr.13, Fr.14, Fr.15, Fr.16).

[0047] (4) After adding Fr.16 (102.5 g) to MCI and mixing the sample, gradient elution was performed using methanol / water with a volume ratio of 50:50 to 100:0 as the eluent for MCI column chromatography. The gradient elution was as follows: first elution with a methanol / water mixture with a volume ratio of 50:50, then elution with a methanol / water mixture with a volume ratio of 60:40, then elution with a methanol / water mixture with a volume ratio of 70:30, then elution with a methanol / water mixture with a volume ratio of 80:20, then elution with a methanol / water mixture with a volume ratio of 90:10, and finally elution with methanol. The eluted fractions were analyzed by TLC and similar fractions were combined to form 12 fractions (Fr.16.1, Fr.16.2, Fr.16.3, Fr.16.4, Fr.16.5, Fr.16.6, Fr.16.7, Fr.16.8, Fr.16.9, Fr.16.10, Fr.16.11, Fr.16.12).

[0048] (5) After adding 40-80 mesh silica gel to Fr.16.8 (11.0 g), the sample was fractionated by normal silica gel column chromatography with 200-300 mesh. The gradient elution was performed by first elution with a mixed solution of petroleum ether and ethyl acetate at a mass ratio of 8:1, then elution with a mixed solution of petroleum ether and ethyl acetate at a mass ratio of 6:1, then elution with a mixed solution of petroleum ether and ethyl acetate at a mass ratio of 4:1, then elution with a mixed solution of petroleum ether and ethyl acetate at a mass ratio of 2:1, and finally elution with a mixed solution of petroleum ether and ethyl acetate at a mass ratio of 1:1. The TLC analysis combined similar fractions and divided them into 5 components (Fr.16.8.1, Fr.16.8.2, Fr.16.8.3, Fr.16.8.4, Fr.16.8.5).

[0049] (6) Fr.16.8.2 Further purification was carried out by semi-preparative HPLC with a mobile phase of a mixed solvent of methanol / water in a volume ratio of 58:42. The peak was collected at a retention time of 12.6 min to obtain compound 1 of structural formula (I) (7.1 mg).

[0050] Example 2

[0051] Structural identification of compound 1

[0052] Compound 1 (Sarcanolide F) is a white powder. For example... Figure 1-Figure 10 As shown, its HR-ESI-MS data indicate that its molecular formula is C 36 H 42 O 11 According to m / z 673.2609 (Theoretical value: C) 36 H 42 O 11 (673.2619), with 16 degrees of unsaturation. IR spectral absorption peaks suggest the presence of olefins and carbonyl groups. In the 1D-NMR spectrum (see Table 1.2), 1 H-NMR spectroscopy revealed a set of characteristic structures of lindera sesquiterpenes, including a methylene signal from cyclopropane. d H 1.21 (m), 2H; 0.63 (m), 2H]; 5 methyl groups [ d H 1.85 (s), 3H; 1.82 (dd, J = 7.2, 1.2 Hz), 3H; 1.47 (s), 3H; 1.15 (s), 3H; 0.92 (s), 3H]; 1 methoxy group [ d H 3.75 (s), 3H]; three distinct olefinic hydrogen signals also exist in the low-field region [ d H 6.89 (m), 1H; 6.59 (s), 1H; 5.74 (s), 1H]. [Combined] 13 C-NMR and DEPT spectra revealed 6 methyl groups (including 1 methoxy group), 6 methylene groups, 8 methine groups (including 1 hydroxymethyl group and 2 alkenyl groups) and 16 quaternary carbon groups (including 1 carbonyl carbon and 3 ester carbons) among the 36 carbon signals. Based on these findings, the compound was determined to be a sesquiterpene dimer, with a structure significantly different from classic lindera alkyl sesquiterpene dimers.

[0053] By comprehensively analyzing the 1D-NMR and 2D-NMR spectra, the planar structure of this compound can be determined in detail, and it can be constructed into two partial structures (unit A and unit B) for analysis. HMBC spectroscopy analysis of H-3 ( d H 5.71) and C-1 ( d C 70.1) and C-2 ( d C 32.5) related; H-9 ( d H 4.01) and C-1, C-5 ( d C 71.3) and C-8 ( d C 196.8) related; H-14 ( d H 1.15) and C-1, C-5, C-9 ( d C 78.3) and C-10 ( d C 48.6) related; H-15 ( d H 2.88, 2.48) and C-3 ( d C 121.4) and C-5 are related, combined 1 H- 1 The correlation of H-1 / H-2 / H-3 in H COSY indicates that C-1 and C-9 each have two hydroxyl groups, and C-8 has one carbonyl group. In unit B, the COSY correlation of H-1′ / H-2′ / H-3′ / H-5 / H2-6 and the correlation from H-5′ ( d H 1.91) to C-1′ ( d C 27.1), C-3′ d C 29.3), C-4′ ( d C 78.6), C-7′ ( d C 57.1), C-9′ ( d C 48.3) and C-15′ d C The HMBC cross peak at 70.2) and from H-13′ ( d H 6.59, 5.74) to C-7′, C-11′ ( d C 143.5) and C-12′ d C The HMBC cross peaks at 168.1 indicate that unit B is a classic lindera sesquiterpene monomer with an α,β-unsaturated ketone structure. Unit A and unit B are linked through key HMBC interactions H-15 / C-8′, C-9′, and H-13 / C-7′, demonstrating a synergistic effect. , and The connection is shown. Therefore, the planar structure of compound 1 was determined to consist of one molecule of a eucalyptane-type sesquiterpene monomer and one molecule of a linderane-type sesquiterpene monomer. The relative configuration of compound 1 was determined based on NOESY spectral analysis, H-15. β ( d H 2.88) / H-2′ β ( d H1.21) / H-9′ ( d H 3.07) / H-14′ d H The presence of a correlation signal (0.92) indicates that they are all located on the same side. β configuration 。 H-1 ( d H 4.10) / H-9 ( d H 4.01), H-3′ ( d H 1.65) / H-5′ ( d H NOESY correlation analysis (1.91) showed that H-1, H-9, H-3′, and H-5′ were... α Configuration. Finally, through quantum computational chemistry, the absolute configuration of compound 8 was determined to be 1 by comparing the experimental and calculated ECD curves. R 5 S 9 R 10 R 11 R 1′ R 3′ S 4′ S 5′ R 7′ R 8′ R 9′ S 10′ S .

[0054]

[0055] Example 3

[0056] The in vitro anti-inflammatory activity of the compound of the present invention

[0057] Experimental methods

[0058] 1. Cell Culture

[0059] After resuscitation, BV-2 cells were passaged in DMEM high-glucose medium [containing 10% fetal bovine serum (FBS) and penicillin-streptomycin antibiotics] under constant temperature cell culture conditions of 37 ℃ and 5% CO2. Once the BV-2 cells were in good growth condition, cells in the logarithmic growth phase were collected to prepare a cell suspension, counted using a hemocytometer, and then the cell density was adjusted to 2.78 × 10⁻⁶. 5Cells / mL. Subsequently, the cell suspension was seeded into 96-well plates at a rate of 90 µL / well and cultured at 37 ℃ in a 5% CO2 incubator for 24 h. Three experimental groups were set up in the 96-well plates: a blank control group, a model group, and a drug-treated group. Each experimental group had three replicates. The blank control group and the model group each had one well, and the rest were drug-treated groups.

[0060] 2. MTT assay to determine the effect of compounds on BV-2 cell viability

[0061] Remove the 96-well plate from the incubator after 24 hours of culture. Dilute all prepared compound stock solutions (20 mM) to 400 μM with culture medium, then add 10 µL / well to the drug-treated group to achieve a final compound concentration of 40 μM. After incubating at 37 ℃ and 5% CO2 for two hours, add 10 μL LPS (1 mg / mL LPS stock solution diluted 100 times with culture medium to 10 μg / mL) to each well in both the model group and the drug-treated group. Continue culturing the cells under the same conditions for another 24 hours. After the culture period, add 10 μL MTT staining agent (5 mg / mL) to each well, and then incubate the 96-well plate at 37 ℃ and 5% CO2 for another 4 hours. Subsequently, carefully aspirate the supernatant, add 150 μL DMSO to each well, and place the 96-well plate in a 37 ℃ constant temperature shaker for 15 minutes until the formazan crystals are completely dissolved. Finally, the absorbance (A) value of each well was measured using an ELISA reader, and the cell viability was calculated according to the formula.

[0062] Calculation formula:

[0063] Survival rate (%) = (OD value of experimental group - OD value of blank group) / (OD value of control group - OD value of blank group) × 100%.

[0064] Cell viability was determined by the MTT assay, and compounds 1, 2, and 3 were all non-toxic at a concentration of 40 μM.

[0065] 3. Griess method for detecting the inhibitory effect of compounds on LPS-induced NO release from BV-2 cells

[0066] Remove the prepared 96-well plate from the incubator and add 10 μL of the test sample with a final concentration of 20 μM to each well. Incubate for another 2 h. Then, add 10 μL of LPS (10 μg / mL) to each well in both the model group and the drug-treated group. After incubating for another 24 h at 37 ℃ and 5% CO2, aspirate 50 μL of the supernatant from each well and add 50 μL each of Griess reagent I and II to the supernatant. Finally, use a microplate reader to detect the absorbance of each well at 540 nm and calculate the inhibition rate of NO production by the compound. The experiment was repeated three times, and the average value was taken. Compounds with a NO inhibition rate greater than 60% were then selected and diluted with culture medium to prepare six different concentrations. The above steps were repeated, and the absorbance at each concentration was measured. Minocycline was used as a positive control drug in each experiment. A cell growth curve was plotted with compound concentration on the x-axis and NO inhibition rate on the y-axis. The half-maximal inhibitory concentration (IC50) of the compound was calculated using the Reed-Muench method. 50 The experiment was repeated three times, and the results were averaged. The results are as follows: Figure 11 As shown in the figure. The results indicate that compound 1 inhibits LPS-induced NO production in BV-2 cells. Further IC50 analysis... 50 Test results show that compound 1 has an IC50 value. 50 The value was 4.09 ± 1.42 μM, and its effect was superior to that of the positive control drug minocycline (18.89 ± 3.69 μM).

[0067] 4. Western blot analysis of the expression of NF-κB signaling pathway-related proteins COX-2, iNOS, and MYD88.

[0068] Take BV-2 cells in the logarithmic growth phase and use 80×10⁻⁶ cells. 4Cells were seeded per well in 6-well plates and incubated at 37 °C with 5% CO2 for 24 h. Final drug concentrations of 2, 5, and 10 μM were set for each well. After 2 h of incubation, 1.5 μL of LPS (1 mg / mL) was added to each well (except for the control group). 24 h after drug administration, the supernatant was discarded, and cells were washed twice with PBS. Total protein was extracted using SDS cell lysis buffer containing 1% PMSF and a phosphorylated protease inhibitor. The total protein concentration was determined using a BCA kit, and the proteins were denatured at 95 °C. After separation by electrophoresis on a 10% SDS-PAGE separating gel, the proteins were transferred to a PVDF membrane, blocked with 5% BSA, and incubated overnight with primary antibody at 4 °C. The membrane was then incubated with secondary antibody at room temperature for 1 hour and washed with TBST. Protein bands were then detected using a BeyoECL PLUS kit. The experiment was repeated in triplicate. Results are shown below. Figure 12 As shown, compared with the blank control group, the expression levels of COX-2, iNOS, and MYD88 proteins in BV-2 cells of the model group (only LPS was added) were significantly increased. In contrast, the protein expression of COX-2, iNOS, and MYD88 in the treatment groups (final concentrations of compound 1 were 2, 5, and 10 μM, respectively) was significantly decreased in a dose-dependent manner. These mechanistic results indicate that compound 1 exerts its anti-neuroinflammatory effect by regulating the NF-κB and MYD88 signaling pathways. Therefore, compound 1, due to its novel structure and activity, should be considered a novel neuroprotective agent.

[0069] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

Claims

1. A sesquiterpene dimer compound, characterized in that: Extracted from *Sarcandra glabra*, its chemical structural formula is shown in formula (I): 。 2. A method for preparing the sesquiterpene dimer compound according to claim 1, characterized in that: Includes the following steps: 1) After the grass coral is dried, it is crushed, extracted with organic solvent, and then extracted by hot reflux and concentrated under reduced pressure to recover the solvent, so as to obtain crude extract. 2) The crude extract was suspended in water and extracted sequentially with organic solvents. The organic solvents were then recovered to obtain the extract of Coral Gynostemma pentaphyllum. 3) The extract of *Sarcandra glabra* from step 2) was eluted with a normal-phase silica gel gradient using dichloromethane / methanol at a volume ratio of 100:0 to 0:

100. Thin-layer chromatography was then used to detect the fractions that showed fluorescence under UV light and / or the chromogenic fractions developed by 5% sulfuric acid ethanol, respectively, to obtain fractions Fr.1 to Fr.

16. 4) The Fr.16 from step 3) was subjected to gradient elution by MCI GEL CHP20P column chromatography with methanol / water at a volume ratio of 50:50~100:

0. Thin-layer chromatography was then used to detect the fluorescence under UV light and / or the colorimetric fraction of 5% sulfuric acid ethanol, respectively, to obtain the Fr.16.1~Fr.16.12 fractions. 5) Elute Fr.16.8 from step 4) with a normal-phase silica gel gradient using petroleum ether / ethyl acetate at a volume ratio of 8:1 to 1:1, and then detect the elution by thin-layer chromatography. Collect the components that fluoresce under UV light and / or the colorimetric components of 5% sulfuric acid ethanol to obtain the components Fr.16.8.1 to Fr.16.8.8, respectively. 6) The Fr.16.8.6 from step 5) was subjected to Sephadex LH-20 column chromatography with dichloromethane / methanol at a volume ratio of 1:1 as the eluent, and then detected by thin-layer chromatography. The components that fluoresce under UV light and / or the colorimetric components of 5% sulfuric acid ethanol were collected sequentially to obtain the components Fr.16.8.6.1 to Fr.16.8.6.5, respectively. 7) Fr.16.8.6.5 from step 6) was further purified by semi-preparative HPLC. Methanol / water with a volume ratio of 58:42 was selected as the mobile phase, and the chromatographic peak was collected at a retention time of 15 min to obtain the compound shown in formula (I).

3. The method for preparing the sesquiterpene dimer compound according to claim 2, characterized in that, In step 1), the organic solvent is 95% ethanol, and the volume of ethanol used is 3~5 L / kg based on the weight of the Coral Gum powder. The reflux extraction is performed at least 3 times, and the extraction time is 2 h each time.

4. The method for preparing the sesquiterpene dimer compound according to claim 2, characterized in that, The organic solvents mentioned in step 2) are petroleum ether and ethyl acetate. The crude extract is extracted with petroleum ether and ethyl acetate 5-6 times each. The volume of water used for water suspension is 2-5 L / kg based on the weight of the crude extract. The volume ratio of petroleum ether and ethyl acetate to water is 1:

1.

5. The method for preparing the sesquiterpene dimer compound according to claim 2, characterized in that, In step 3), the elution conditions for silica gel column chromatography are as follows: gradient elution is performed using dichloromethane / methanol mixed solvent with volume ratios of 100:0, 100:1, 50:1, 25:1, 10:1, 5:1, 2:1, 1:1, and 0:

1.

6. The method for preparing the sesquiterpene dimer compound according to claim 2, characterized in that, In step 4), the elution conditions for MCIGEL CHP20P column chromatography are as follows: gradient elution is performed using methanol / water mixed solvents with volume ratios of 50:50, 60:40, 70:30, 80:20, 90:10, and 100:

0.

7. The use of the sesquiterpene dimer compound of claim 1 in the preparation of a neuritis inhibitor, characterized in that, The neuritis inhibitor suppresses the expression level of the protein.

8. The application as described in claim 7, characterized in that, The proteins are COX-2, INOS, MYD88, and p-iκBα.

9. The use of the sesquiterpene dimer compound of claim 1 in the preparation of an anti-inflammatory drug.

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