Xanthone compound as well as preparation method and application thereof

Abstract

The invention discloses xanthone compounds as well as a preparation method and application thereof, the xanthone compounds are obtained by taking stems and leaves of dry Garciniaceae Rhodophyllum plants as raw materials through extract extraction, organic solvent extraction, silica gel column chromatography and high performance liquid chromatography separation, and the molecular formula of the xanthone compounds is C20H20O8. The compound provided by the invention belongs to a novel xanthone structure, can reduce the generation of reactive oxygen species (ROS) in juvenile zebrafish bodies, has an anti-oxidation effect, can be used for preparing anti-reactive oxygen species (ROS) drugs, and has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of plant active ingredient extraction, and particularly to a xanthone compound, a preparation method thereof, and an application thereof. Background Art

[0002] There are about 180 species of plants in the genus Calophyllum (Calophyllum L.) of the family Clusiaceae. There are 4 species in China (Calophyllum blancoi Planch. et Triana, Calophyllum inophyllum L., Calophyllum membranaceum Gardn. et Champ., Calophyllum polyanthum Wall. ex Choisy). Among them, the roots of Calophyllum membranaceum are used medicinally among the people to treat traumatic injuries, rheumatic bone pain, and kidney deficiency low back pain, and can disperse stasis and relieve pain, tonify the kidney and strengthen the waist; the leaves are used to treat external bleeding. Calophyllum polyanthum is used in traditional Chinese medicine to treat traumatic bleeding and relieve pain. Its seed oil is often used to treat skin wounds and scabies. The main chemical components of plants in the genus Calophyllum are xanthones, chromanone derivatives, coumarins, flavonoid compounds, triterpenoid compounds, etc.; these compounds exhibit various activities such as antioxidant, cytotoxic, anti-HIV, antibacterial, anti-tumor, anti-parasitic, and mitochondrial respiration.

[0003] How to more effectively utilize the plant resources of the genus Calophyllum in the family Clusiaceae and find active ingredients with development prospects therefrom is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The first object of the present invention is to provide a xanthone compound; the second object is to provide a preparation method of the xanthone compound; the third object is to provide an application of the xanthone compound in the preparation of anti-reactive oxygen species (ROS) drugs.

[0005] The first object of the present invention is achieved as follows. A xanthone compound is obtained by using the dried stems and leaves of plants in the genus Calophyllum of the family Clusiaceae as raw materials, through extract extraction, organic solvent extraction, silica gel column chromatography, and high performance liquid chromatography separation. The molecular formula of the xanthone compound is C 20 H 20 O8; in the present invention, this xanthone compound is named caledonixanthone M.

[0006] The structural formula of the xanthone compound is:

[0007]

[0008] The second object of the present invention is achieved as follows. A method for preparing xanthone compounds comprises the following steps:

[0009] A. Extracting the extract: Coarsely pulverize the stems and leaves of the plant of the genus Calophyllum in the family Clusiaceae to 20-40 mesh, and ultrasonically extract with an organic solvent 3-4 times, 30-40 minutes each time. Combine the extracts; filter the extract, and concentrate the extract under reduced pressure to 1 / 4-1 / 2 of its volume. Let it stand, filter off the precipitate, and concentrate it into extract a;

[0010] B. Extracting with an organic solvent: Add 1-2 times the weight of water to extract a, and extract with an organic solvent of the same volume as water 3-5 times. Combine the organic solvent extraction phases and concentrate under reduced pressure to obtain extract b;

[0011] C. Silica gel column chromatography: Dissolve extract b in an organic solvent 1.5-3 times its weight, then mix it with silica gel of 80-100 mesh, 0.8-1.2 times the weight of the extract, and then perform silica gel column chromatography. The silica gel for packing the column is 180-300 mesh, and the dosage is 6-8 times the weight of extract b; Gradient elute with a mixed organic solvent with a volume ratio of 1:0-0:1, collect the gradient eluate, concentrate it, and monitor by TLC. Combine the same parts;

[0012] D. Reverse-phase column chromatography: Load the eluate obtained by eluting with an organic solvent in a ratio of 20:1 onto a reverse-phase column chromatography. The reverse-phase column is packed with a reverse-phase material C-18 or ODS; Gradient elute with a methanol aqueous solution with a volume content of 20-100%, collect each part of the eluate and concentrate it, and monitor by TLC. Combine the same parts;

[0013] E. High-performance liquid chromatography separation: Purify the eluate obtained by eluting with a methanol aqueous solution with a volume content of 70-100% by high-performance liquid chromatography to obtain the xanthone compounds.

[0014] Specifically, in step E, the high-performance liquid chromatography separation and purification uses methanol at 80-100% as the mobile phase, the flow rate is 3 ml / min, a reverse-phase preparative column of 10×250 mm and 5 μm is used as the stationary phase, the detection wavelength of the ultraviolet detector is 254 nm, 30-50 μL is injected each time, the chromatographic peaks from 20-50 minutes are collected, and after multiple accumulations, it is evaporated to dryness to obtain the xanthone compounds.

[0015] Among them, in step A, the organic solvent is ethanol or methanol at 80-100%.

[0016] Among them, in step B, the organic solvent is one of dichloromethane, petroleum ether, and chloroform.

[0017] Among them, in step C, the mixed organic solvent is dichloromethane-methanol, or dichloromethane-ethyl acetate, or chloroform-ethyl acetate, or chloroform-acetone, or petroleum ether-ethyl acetate.

[0018] Among them, in step C, the volume ratio of the mixed organic solvent is one of 1:0, 20:1, 9:1, 8:2, 7:3, 3:2, 1:1, 1:2, 0:1.

[0019] The xanthone compounds of the present invention are isolated for the first time, determined to be xanthone compounds by nuclear magnetic resonance and other spectroscopic determination methods, and their specific structures are characterized as:

[0020]

[0021] Upon identification, compound caledonixanthone M is a yellow amorphous solid; ultraviolet spectrum (solvent is methanol), λ max : 194, 238, 252, 310, 362 nm; infrared spectrum (KBr pellet) ν max 3441, 2879, 1621, 1599, 1494, 1464, 1366, 1269, 1230 cm -1 ; HRESIMS shows that the quasi-molecular ion peak of the compound of the present invention is m / z 389.1281 [M+H]+, (calculated value 389.1231), combined with 13 C and 1 H NMR spectra ( Figure 1 and Figure 2 , the data attribution of carbon spectrum and hydrogen spectrum is shown in Table 1) gives its molecular formula as C 20 H 20 O8. 1 H NMR (CD3OD, 600 MHz) and 13 C NMR (CD3OD, 125 MHz) data are shown in Table 1.

[0022] HRESIMS shows that its quasi-molecular ion peak is the quasi-molecular ion peak m / z 389.1281 [M+H]+, (calculated value 389.1231), combined with 13 C NMR spectrum to determine the molecular formula as C 20 H 20 O8, and the degree of unsaturation is 11. The 1 H- and 13 C-NMR data attribution is shown in Table 1. The 13 C NMR spectrum of this compound shows the presence of a xanthone skeleton [δ C182.7 (C-9), 163.2 (C-1), 161.3 (C-8), 156.7 (C-4a), 155.8 (C-6), 151.7 (C-4b), 137.3 (C-3), 136.7 (C-5), 114.2 (C-7), 111.6 (C-8a), 110.4 (C-9a), 109.8 (C-2), 107.6 (C-4)], and the 1 1H-NMR spectrum of this compound shows that there is a hydroxyl proton at δ H 13.14 (1H, s, OH-1), three aromatic protons (δ H 6.74, d, J = 8.3 Hz; δ H 7.59, t, J = 8.3 Hz; δ H 6.97, d, J = 8.3 Hz), a gem - dimethyl functional group (δ H 1.35 and 1.33), and two methoxy groups ((δ H 3.98 and 3.99). Based on these spectral data, it is speculated that this compound is a xanthone - type compound, and its chemical structure is similar to caledonixanthone J, except for two additional methoxy groups in the compound. By comparing with caledonixanthone J, 1 the 1H - NMR (δ H 5.70, d, J = 3.5 Hz; δ H 4.55, d, J = 3.5 Hz) spectrum shows the presence of 3,4 - cis - dihydroxy - 2,2 - dimethylchroman in the molecule. In the HMBC spectrum of this compound, the quaternary oxygen carbon of the chroman ring [δ C 71.8 (C - 3′)] is correlated with H - 1′, H - 2′, and the aforementioned gem - dimethyl protons. Therefore, these elements characterize the 3,4 - dihydroxy - 2,2 - dimethylchroman moiety. The HSQC spectrum confirms the carbon - hydrogen assignments of the same carbon, δ H 3.99 and 5 - OMe (δ C 61.7) and δ H 3.98 and 6 - OMe (δ C 62.8) are correlated. In addition, the HMBC spectrum shows that δ H 3.99 is correlated with C - 5 (δ H 136.7) and δ H 3.98 is correlated with C - 6 (δ C 155.8), proving that the methoxy groups are attached to C - 5 and C - 6 respectively. Figure 2)。These results indicate that the compound may have a 1-hydroxy-5,6-dimethoxy-7,8-disubstituted xanthone structure. According to the molecular formula and nuclear magnetic resonance spectrum, C-2′ and C-1′ should be substituted by hydroxyl groups respectively. Based on the above, the structure of the compound can be deduced, and the compound is determined to be caledonixanthone M.

[0023] The third object of the present invention is achieved as follows. The application of the xanthone compound in the preparation of anti-reactive oxygen species (ROS) drugs. Through the zebrafish reactive oxygen species inhibition activity experiment, using vitamin C as the positive control, caledonixanthone M can significantly inhibit the aggregation of reactive oxygen species (ROS) in zebrafish larvae, and it has good antioxidant activity. The compound of the present invention has a simple structure and good activity, can be used as a lead compound for anti-reactive oxygen species (ROS) drugs, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the carbon nuclear magnetic resonance spectrum ( 13 C NMR) of compound caledonixanthone M;

[0025] Figure 2 is the proton nuclear magnetic resonance spectrum ( 1 H NMR) of compound caledonixanthone M;

[0026] Figure 3 is the main HMBC correlation spectrum of compound caledonixanthone M;

[0027] Figure 4 is the situation of compound caledonixanthone M inhibiting reactive oxygen species (ROS) in zebrafish. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] To make the objectives, features, and advantages of the present invention more obvious and understandable, the following provides a detailed description of the specific embodiments of the present invention with reference to the accompanying drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0029] The present invention will be described in different embodiments below. The Garcinia plants in each embodiment are not restricted by region and variety, and all can implement the present invention.

[0030] Example 1

[0031] Take 3.8 kg of the stems and leaves of the plant Calophyllum inophyllum L. of the family Clusiaceae, coarsely crush them to 20 mesh, and ultrasonically extract them 3 times with 85% ethanol for 30 minutes each time. Combine the extraction solutions; filter the extraction solution, and concentrate it under reduced pressure to 1 / 3 of its original volume; let it stand, filter off the precipitate, and concentrate it into 80 g of extract a; add 89 g of water to extract a, and extract it 3 times with dichloromethane with the same volume as water. Combine the extraction phases and concentrate them under reduced pressure to 30 g of extract b; pack a column with 240 g of silica gel with a mesh size of 200 - 300, dissolve extract b in 45 mL of dichloromethane, then add 30 g of silica gel with a mesh size of 100 for sample mixing. After sample mixing, load the sample onto the column; elute it with a gradient of dichloromethane - methanol mixed organic solvents with volume ratios of 1:0, 100:1, 50:1, 20:1, 10:1, 4:1, 6:4, 1:1, 0:1 respectively. Collect the gradient elution solution, concentrate it, monitor it by TLC, and combine the same parts; the elution solution c of the dichloromethane - methanol mixed organic solvent with a volume ratio of 20:1 is 5 g; pack a column with reverse-phase material C-18, load elution solution c onto the reverse-phase column, and perform gradient elution with a methanol aqueous solution with a volume content of 20 - 100%. Collect each part of the elution solution and concentrate it, monitor it by TLC, and combine the same parts; take the elution solution eluted with a methanol aqueous solution with a volume content of 70 - 100%, then use 90% methanol as the mobile phase, with a flow rate of 3 ml / min, a 10×250 mm, 5 μm Neptune EC-C18 column as the stationary phase, a detection wavelength of 254 nm for the ultraviolet detector, inject 30 μL each time, collect the chromatographic peaks for 45 minutes, and after multiple accumulations, evaporate to dryness to obtain the xanthone compound caledonixanthone M.

[0032] Example 2

[0033] Take 5.7 kg of the stems and leaves of plants in the genus Calophyllum in the family Clusiaceae, coarsely crush them to 30 mesh, and ultrasonically extract with 70% methanol 4 times, each time for 35 minutes, and combine the extracts; filter the extract, and concentrate it under reduced pressure to 1 / 2 of the original volume; let it stand, filter off the precipitate, and concentrate it into 149 g of extract a; add 200 g of water to extract a, and extract with chloroform of the same volume as water 4 times, combine the extraction phases, and concentrate it under reduced pressure to 54 g of extract b; pack a column with 430 g of silica gel of 200 - 300 mesh, dissolve extract b in 50 mL of ethyl acetate, then add 64 g of silica gel of 80 - 100 mesh for sample mixing, and load the sample onto the column after mixing; elute with a gradient of dichloromethane - ethyl acetate mixed organic solvents with volume ratios of 1:0, 100:1, 20:1, 9:1, 8:2, 7:3, 6:4, 1:1, 0:1 respectively, collect the gradient eluate, concentrate it, monitor by TLC, and combine the same parts; the eluate c of the dichloromethane - ethyl acetate mixed organic solvent with a volume ratio of 20:1 is 7 g; pack a column with reverse-phase material ODS, load eluate c onto the reverse-phase column, and perform gradient elution with a methanol aqueous solution with a volume content of 20 - 100%, collect each part of the eluate and concentrate it, monitor by TLC, and combine the same parts; take the eluate eluted with a methanol aqueous solution with a volume content of 70 - 100%, then use 86% methanol as the mobile phase, with a flow rate of 3 ml / min, a 10×250 mm, 5 μm Neptune EC-C18 column as the stationary phase, the detection wavelength of the ultraviolet detector is 254 nm, inject 50 μL each time, collect the chromatographic peak for 50 minutes, accumulate it multiple times and then evaporate to dryness to obtain the xanthone compound caledonixanthone M as described above.

[0034] Example 3

[0035] Take 10.0 kg of the stems and leaves of Garcinia oblongata, coarsely crush them to 40 mesh, extract with 90% ethanol three times, each time for 40 min, and combine the extracts; filter the extract, and concentrate it under reduced pressure to 1 / 4 of its original volume; let it stand, filter off the precipitate, and concentrate it into 301 g of extract a; add 320 g of water to extract a, extract with ethyl acetate of the same volume as water four times, combine the extraction phases, and concentrate it under reduced pressure to 120 g of extract b; pack a column with 960 g of silica gel of 200 mesh, dissolve 160 mL of methanol in extract b, then add 130 g of silica gel of 100 mesh for sample mixing, and load the sample onto the column after mixing; elute with a gradient of petroleum ether-ethyl acetate mixed organic solvents with volume ratios of 1:0, 20:1, 9:1, 8:2, 7:3, 3:2, 1:1, 1:2, 0:1 respectively, collect the gradient eluate, concentrate it, monitor by TLC, and combine the same parts; the eluate c of the petroleum ether-ethyl acetate mixed organic solvent with a volume ratio of 20:1 is 16 g; pack a column with reverse-phase material C-8, load eluate c onto the reverse-phase column, perform gradient elution with a methanol aqueous solution with a volume content of 20-100%, collect each part of the eluate and concentrate it, monitor by TLC, and combine the same parts; take the eluate eluted with a methanol aqueous solution with a volume content of 80-100%, then use 93% methanol as the mobile phase, with a flow rate of 3 ml / min, a 10×250 mm, 5 μm Neptune EC-C18 column as the stationary phase, and the detection wavelength of the ultraviolet detector is 254 nm, collect the chromatographic peak for 35 min, evaporate to dryness after multiple accumulations, and thus obtain the xanthone compound caledonixanthone M.

[0036] Example 4

[0037] Take the compound caledonixanthone M prepared in Example 1, which is a yellow amorphous solid; the determination method is: identify the structure by nuclear magnetic resonance, combined with other spectroscopic techniques.

[0038] (1) Ultraviolet spectrum (solvent is methanol), λ max : 194, 238, 252, 310, 362 nm;

[0039] (2) Infrared spectrum (KBr tablet) ν max 3441, 2879, 1621, 1599, 1494, 1464, 1366, 1269, 1230 cm -1 ;

[0040] (3) HRESIMS shows that the quasi-molecular ion peak of the compound of the present invention is m / z 389.1281 [M+H]+, (calculated value 389.1231), combined with 13 C and 1 H NMR spectrum ( Figure 1 andFigure 2 The carbon spectrum and hydrogen spectrum data attribution are shown in Table 1), and its molecular formula is C 20 H 20 O8. 1 1H NMR (600 MHz, CD3OD) and 13 13C NMR (125 MHz, CD3OD) data are shown in Table 1.

[0041] HRESIMS shows that its quasi-molecular ion peak is the quasi-molecular ion peak m / z 389.1281 [M+H]+, (calculated value 389.1231). Combining with 13 the 13C NMR spectrum, the molecular formula is determined to be C 20 H 20 O8, and the degree of unsaturation is 11. The 1 1H- and 13 13C-NMR data attribution are shown in Table 1. The 13 13C NMR spectrum of this compound shows the presence of a xanthone skeleton [δ C 182.7 (C-9), 163.2 (C-1), 161.3 (C-8), 156.7 (C-4a), 155.8 (C-6), 151.7 (C-4b), 137.3 (C-3), 136.7 (C-5), 114.2 (C-7), 111.6 (C-8a), 110.4 (C-9a), 109.8 (C-2), 107.6 (C-4)], and the 1 1H-NMR spectrum of this compound shows a hydroxyl proton at δ H 13.14 (1H, s, OH-1), three aromatic protons (δ H 6.74, d, J = 8.3 Hz; δ H 7.59, t, J = 8.3 Hz; δ H 6.97, d, J = 8.3 Hz), a gem-dimethyl functional group (δ H 1.35 and 1.33) and two methoxy groups (δ H 3.98 and 3.99). Based on these spectral data, it is speculated that this compound is a xanthone compound, and its chemical structure is similar to that of caledonixanthone J, except for two additional methoxy groups in the compound. By comparing with caledonixanthone J, 1 1H-NMR (δ H 5.70, d, J = 3.5 Hz; δ H 4.55, d, J = 3.5 Hz) spectrum shows the presence of 3,4-cis-dihydroxy-2,2-dimethylchroman in the molecule. In the HMBC spectrum of this compound, the quaternary oxygen carbon of the chroman ring [δC Both 71.8 (C-3′)] are related to H-1′, H-2′ and the aforementioned gem-dimethyl protons. Therefore, these elements characterize the 3,4-dihydroxy-2,2-dimethylchroman moiety. The HSQC spectrum confirmed the homonuclear proton-carbon assignments, δ H 3.99 and 5-OMe (δ C 61.7) and δ H 3.98 and 6-OMe (δ C 62.8) are related. In addition, the HMBC spectrum showed that δ H 3.99 and C-5 (δ H 136.7) are related and δ H 3.98 and C-6 (δ C 155.8) are related, proving that the methoxy groups are attached to C-5 and C-6 respectively ( Figure 3 ). These results suggest that the compound may have a 1-hydroxy-5,6-dimethoxy-7,8-disubstituted xanthone structure. Based on the molecular formula and nuclear magnetic resonance spectrum, C-2′ and C-1′ should be substituted by hydroxyl groups respectively. From the above, the structure of the compound can be deduced, and the compound is determined to be caledonixanthone M.

[0042] Example 5

[0043] Take the compound prepared in Example 2, which is a yellow amorphous solid; perform structure determination according to the method in Example 4, and the results are as follows: its structure is the same as that in Example 4, and the molecular formula is C 20 H 20 O8. It is confirmed that the compound prepared in Example 2 is the xanthone compound caledonixanthone M.

[0044] Example 6

[0045] Take the compound prepared in Example 3, which is a yellow amorphous solid; perform structure determination according to the method in Example 4, and the results are as follows: its structure is the same as that in Example 4, and the molecular formula is C 20 H 20 O8. It is confirmed that the compound prepared in Example 3 is the xanthone compound caledonixanthone M.

[0046] Table 1 1 H and 13 C NMR data (600 / 125 MHz, CD3OD)

[0047]

[0048]

[0049] Example 7

[0050] The xanthone compounds prepared in Example 1 were subjected to an in vivo reactive oxygen species scavenging activity detection test, and the test results are as follows:

[0051] The generation of many diseases is related to the inactivation of proteins, nucleic acids, lipids and other molecules caused by the oxidation of reactive oxygen species (ROS). The ROS regulation mechanism in zebrafish is the same as that in humans. Using a specific reactive oxygen species fluorescent staining reagent, ROS in zebrafish embryo cells can be efficiently and specifically labeled, and at this time its fluorescence intensity is positively correlated with the intracellular ROS level. Software is used to analyze and quantitatively read the green fluorescent signal that increases with the increase of ROS in zebrafish embryos, and the changes in the ROS levels of fish embryos in the treatment group and the blank control group are tested and compared, and the ROS scavenging rate is calculated to evaluate the in vivo antioxidant ability of the compound.

[0052] Activity determination method

[0053] (1) Wild zebrafish embryos were obtained by natural pairing. Zebrafish embryos and larvae were cultured in E3 medium (3.4 μM KCl, 1 mM NaCl, 6.6 μM MgSO4 and CaCl2) at a 14-hour:10-hour day-night cycle at 28.0 ± 0.5 °C.

[0054] (2) A blank control group (fish embryo culture medium), a positive control group (10 μg / mL vitamin C working solution) and a test drug group (1 μg / mL) were set up.

[0055] (3) Fertilized embryos were selected using a stereomicroscope and transferred to a six-well polystyrene plate, with 10 fish per well, and treated with the test samples, and then placed in an incubator at 28 ± 1 °C and cultured until 72 ± 1 h after fertilization.

[0056] (4) Zebrafish larvae treated with the test samples were stained with 0.1% ROS (DCF-DA) staining solution at 37 °C for 30 minutes in the dark, and then washed 5 times with 0.003% PTU in the dark.

[0057] (5) Then the fish were photographed under an inverted fluorescence microscope (Leica TCS SP5, Germany) at the same magnification. ImageJ (NIH) was used to calculate the fluorescence intensity of ROS staining.

[0058] The results are as Figure 4 shown. The xanthone compound caledonixanthone M of the present invention can significantly inhibit the aggregation of reactive oxygen species ROS in zebrafish larvae, and the effect is equivalent to that of the positive control vitamin C.

[0059] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0060] The above-described embodiments merely represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A xanthone compound, characterized in that, The xanthone compound is obtained from the stems and leaves of plants of the genus Calophyllum in the family Guttiferae after drying, through processes such as extract preparation, organic solvent extraction, silica gel column chromatography, and high performance liquid chromatography separation. The molecular formula of the xanthone compound is C 20 H 20 O8; The structural formula of the xanthone compound is as follows:

2. The preparation method of the xanthone compound according to claim 1, characterized in that, It includes the following steps: A. Extracting the extract: Coarsely pulverize the stems and leaves of the plant of the genus Calophyllum in the family Clusiaceae to 20 - 40 mesh, and ultrasonically extract with an organic solvent 3 - 4 times, each time for 30 - 40 min, and combine the extraction solutions; filter the extraction solution, and when the extraction solution is concentrated under reduced pressure to 1 / 4 - 1 / 2 of its volume, let it stand, filter off the precipitate, and concentrate it into extract a; B. Extracting with an organic solvent: Add water in an amount 1 - 2 times the weight of extract a, and extract with an organic solvent of the same volume as water 3 - 5 times, combine the organic solvent extraction phases, and concentrate under reduced pressure into extract b; C. Silica gel column chromatography: Dissolve extract b with an organic solvent in an amount 1.5 - 3 times the weight of extract b, then mix the sample with silica gel of 80 - 100 mesh in an amount 0.8 - 1.2 times the weight of the extract, and then perform silica gel column chromatography. The silica gel for packing the column is 180 - 300 mesh, and the amount used is 6 - 8 times the weight of extract b; Gradient elute with a mixed organic solvent with a volume ratio of 1:0 - 0:1, collect the gradient eluate, concentrate it, and monitor by TLC, and combine the same parts; D. Reverse - phase column chromatography: Load the eluate obtained by eluting with an organic solvent in a ratio of 20:1 onto a reverse - phase column chromatography. The reverse - phase column is packed with a reverse - phase material C - 18 or ODS; Gradient elute with a methanol - aqueous solution with a volume content of 20 - 100%, collect each part of the eluate and concentrate it, and monitor by TLC, and combine the same parts; E. High - performance liquid chromatography separation: Purify the eluate obtained by eluting with a methanol - aqueous solution with a volume content of 70 - 100% by high - performance liquid chromatography to obtain the xanthone compound.

3. The preparation method of the xanthone compound according to claim 2, characterized in that, In step E, for the high - performance liquid chromatography separation and purification, methanol with a concentration of 80 - 100% is used as the mobile phase, the flow rate is 3 ml / min, a reverse - phase preparative column of 10×250 mm, 5 μm is used as the stationary phase, the detection wavelength of the ultraviolet detector is 254 nm, each injection volume is 30 - 50 μL, collect the chromatographic peaks from 20 - 50 min, and after multiple accumulations, evaporate to dryness to obtain the xanthone compound.

4. The preparation method of the xanthone compound according to claim 2, characterized in that, In step A, the organic solvent is ethanol or methanol with a concentration of 80 - 100%.

5. The preparation method of the xanthone compound according to claim 2, characterized in that, In step B, the organic solvent is one of dichloromethane, petroleum ether, and chloroform.

6. The preparation method of the xanthone compound according to claim 2, wherein In step C, the mixed organic solvent is dichloromethane - methanol, or dichloromethane - ethyl acetate, or chloroform - ethyl acetate, or chloroform - acetone, or petroleum ether - ethyl acetate.

7. The preparation method of the xanthone compound according to claim 2, characterized in that, In step C, the volume ratio of the mixed organic solvent is one of 1:0, 20:1, 9:1, 8:2, 7:3, 3:2, 1:1, 1:2, 0:

1.

8. Use of the xanthone compound according to claim 1 in the preparation of a drug against reactive oxygen species (ROS).

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