CN115043719B - Polyketide from fungus, preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of biological medicine, and provides a polyketide from fungi, a preparation method and application thereof, wherein the invention extracts two novel polyketides from fungi, has anti-inflammatory activity, has obvious inhibition activity on the generation of inflammatory factors induced by LPS, and has IC on the generation of inflammatory factors NO induced by LPS ₅₀ The values can reach 3.18+/-0.21 mu M and 4.89+/-0.27 mu M respectively, can obviously inhibit the expression levels of inflammatory factors IL-6, IL-1 beta and TNF-alpha, can be used for preparing anti-inflammatory medicaments, and provides candidate compounds for researching and developing new anti-inflammatory medicaments.

Description

Polyketide from fungus, preparation method and application thereof

Technical Field

The invention relates to the technical field of biological medicine, in particular to a polyketone compound from fungus, a preparation method and application thereof.

Background

Microglia represent a special population of macrophage-like cells in the central nervous system, which are resident immune cells of the brain, involved in regulating brain development, maintaining the neural environment and repairing lesions. Alterations in microglial function are associated with brain development, aging, and neurodegeneration. Microglia produce pro-inflammatory cytokines including IL-1α, IL-1β, IL-6, and small molecule messengers (including prostaglandins, nitric oxide, and reactive oxygen species) when pathological lesions such as infections, wounds, ischemia, and toxins cause inflammatory responses in the central nervous system. Sustained inflammatory responses can lead to neurodegenerative diseases such as alzheimer's disease, parkinson's disease, multiple sclerosis and amyotrophic lateral sclerosis. The compounds inhibit microglial-mediated neuroinflammation potentially as a method of treating neurodegenerative diseases.

Alternaria fungi are mostly saprophytic or pathogenic species. Alternaria alternata is one of important economic fungi in the world, most of the Alternaria alternata is parasitic on plants, and mainly invades various economic crops, so that serious yield loss is caused, such as cabbage black spot, onion purple spot, corn leaf spot, wheat leaf blight and other diseases. In addition, the alternaria can generate a plurality of secondary metabolites, and researches show that the secondary metabolites of the alternaria have obvious physiological functions of resisting cancer, killing insects or resisting bacteria, and the alternaria fungus is a very promising bioactive compound resource. Therefore, it is necessary to perform systematic chemical component mining and biological activity evaluation on pathogenic bacteria of the genus Alternaria.

At present, the requirements of anti-inflammatory drugs are continuously expanded, and the research and development of the anti-inflammatory drugs with high efficiency, small side effect, low toxicity and broad spectrum has very important significance for human health and social development. In recent years, plant endophytes become new hot spots for natural product development and drug lead compound discovery, and the excavation of active molecules with potential drug targets from metabolites of plant endophytes is one of the important directions of drug development at present.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems in the prior art described above. Therefore, the invention provides a polyketide from fungi, a preparation method and application thereof, and the polyketide is derived from endophytic fungi Alternaria sp.J030, and IC for generating inflammatory factor Nitric Oxide (NO) induced by LPS by the compounds I and II ₅₀ The values can reach 3.18+/-0.21 mu M and 4.89+/-0.27 mu M respectively, has obvious anti-inflammatory activity, can be used for preparing anti-inflammatory lead compounds and anti-inflammatory medicaments, and provides candidate compounds for researching and developing new anti-inflammatory medicaments.

In a first aspect the invention provides a polyketide of fungal origin.

Specifically, a polyketide from fungus has a molecular structure shown in the following formula (I):

R ₁ and R is ₂ Each independently selected from H or benzyl, R ₁ And R is ₂ Not both H and benzyl.

In a second aspect, the invention provides a method for preparing a polyketide of fungal origin.

The invention provides a preparation method of the polyketide, which is separated from a fermentation culture of endophytic fungi Alternaria sp.J030, wherein the strain Alternaria sp.J030 is preserved in the microbiological strain collection center (GDMCC) of Guangdong province, and the address is: guangzhou city first middle road No. 100 college No. 59 building, date of preservation: 2022, 4, 28, deposit number: GDMCC No:62440.

the polyketides protected by the invention are isolated from fermentation cultures of the fungus Alternaria sp.J030, which strain Alternaria sp.J030 has been deposited at the Guangdong province microbiological culture Collection center (GDMCC), address: guangzhou city first middle road No. 100 college No. 59 building, date of preservation: 2022, 4, 28, deposit number: GDMCC No:62440. the invention separates two compounds, which have obvious inhibiting activity on the generation of inflammatory factors induced by LPS, and the compounds I and II can obviously inhibit the expression levels of inflammatory factors IL-6, IL-1 beta and TNF-alpha.

Preferably, the method comprises the following steps:

(1) Activating the endophytic fungus Alternaria sp.J030;

(2) Fermenting and culturing the plant endophytic fungi Alternaria sp.J030 after the activation in the step (1) to obtain a fermentation culture;

(3) Extracting the fermentation culture in the step (2) to obtain a crude extract, and separating and purifying to obtain the polyketide with the molecular structure shown in the formula (I).

Preferably, in step (1), the activation is for 3-7 days at a constant temperature of 25-30 ℃.

Preferably, in step (1), the activation is performed on a PDA plate.

Preferably, the endophytic fungus Alternaria sp.J030 is stored at 4℃in PDA slant medium before activation.

Preferably, in the step (2), the fermentation culture is inoculated into a fermentation medium and cultured at 20-40 ℃ for 20-40 days to obtain a fermentation culture.

Preferably, in the step (2), before the inoculation into the fermentation medium, the method further comprises inoculating the endophytic fungus Alternaria sp.J030 activated in the step (1) onto a plate for cultivation.

Preferably, the culture is carried out in an incubator at 28-30℃for 5-7 days.

Preferably, the fermentation medium is a solid rice fermentation medium.

Preferably, in step (3), the separation is performed by eluting through a silica gel column chromatography and then separating through a Sephadex LH-20 (MeOH) column.

Preferably, the elution system for elution by silica gel column chromatography is petroleum ether and ethyl acetate in a volume ratio of (80:1) - (0:1).

Preferably, in step (3), the fraction of petroleum ether and ethyl acetate in a volume ratio (5:1) - (1:1) is collected at the time of elution.

Preferably, in step (3), the purification is performed using reversed phase C ₁₈ The column was purified by Semi-preparative high performance liquid chromatography (Semi-preparative HPLC) with methanol and water as mobile phases.

Preferably, the volume ratio of the methanol to the water is (60-70): 40-30.

More preferably, the volume ratio of methanol to water is 65:35.

Preferably, the flow rate of the mobile phase is 1-3mL/min.

Preferably, in step (3), the solvent used for the extraction is ethyl acetate.

Preferably, in the step (3), after the extraction, the method further comprises concentrating the extract under reduced pressure to obtain a crude extract.

In a third aspect the invention provides the use of a polyketide of fungal origin.

The invention protects the application of the polyketide in preparing anti-inflammatory drugs.

In a fourth aspect, the invention provides an anti-inflammatory agent.

The invention provides an anti-inflammatory drug, which comprises the polyketide and auxiliary materials.

Compared with the prior art, the invention has the following beneficial effects:

(1) The invention extracts two novel polyketides from fungi, has anti-inflammatory activity and relatively obvious inhibition activity on the generation of inflammatory factors induced by LPS, wherein the IC for the generation of inflammatory factors NO induced by LPS ₅₀ The values can reach 3.18+/-0.21 mu M and 4.89+/-0.27 mu M respectively, can obviously inhibit the expression levels of inflammatory factors IL-6, IL-1 beta and TNF-alpha, can be used for preparing anti-inflammatory medicaments, and provides candidate compounds for researching and developing new anti-inflammatory medicaments;

(2) The preparation method comprises the steps of activating plant endophytic fungi Alternaria sp.J030, preparing a fermentation culture of the plant endophytic fungi Alternaria sp.J030 by a fermentation culture method, and respectively obtaining two novel polyketides by separation and purification technologies.

Drawings

FIG. 1 shows the hydrogen nuclear magnetic resonance spectrum of the compound I prepared in example 1 of the present invention ¹ H NMR spectrum);

FIG. 2 shows nuclear magnetic resonance spectrum of the compound I prepared in example 1 of the present invention ¹³ C NMR spectrum);

FIG. 3 shows the hydrogen-hydrogen chemical shift Guan Pu of the compound I prepared in example 1 of the present invention ¹ H– ¹ H COSY spectrum);

FIG. 4 is a heteronuclear single quantum correlation spectrum (HSQC spectrum) of the compound I prepared in example 1 of the present invention;

FIG. 5 is a heteronuclear multiple bond correlation spectrum (HMBC spectrum) of the compound I prepared in example 1 of the present invention;

FIG. 6 is a high resolution electrospray ionization mass spectrum (HRESIMS) of the compound I prepared in example 1 of the present invention;

FIG. 7 is an infrared spectrum (IR spectrum) of the compound I produced in example 1 of the present invention;

FIG. 8 is an ultraviolet spectrum (UV spectrum) of the compound I prepared in example 1 of the present invention;

FIG. 9 shows a compound II obtained in example 1 of the present invention ¹ H NMR spectroscopy;

FIG. 10 shows a compound II obtained in example 1 of the present invention ¹³ C NMR spectrum;

FIG. 11 shows a compound II obtained in example 1 of the present invention ¹ H– ¹ H COSY profile;

FIG. 12 is a HSQC spectrum of Compound II obtained in example 1 of the present invention;

FIG. 13 is a HMBC spectrum of the compound II prepared in example 1 of the present invention;

FIG. 14 is a HRESIMS spectrum of compound II of the invention prepared in example 1;

FIG. 15 is an IR spectrum of a compound II produced in example 1 of the present invention;

FIG. 16 is a UV spectrum of compound II prepared in example 1 of the present invention;

FIG. 17 is a graph showing the results of MTT assay for cell viability of the compounds I and II of example 1 of the present invention;

FIG. 18 is a graph showing the results of inhibition of LPS-induced NO production by the compounds I and II prepared in example 1 of the present invention;

FIG. 19 is a graph showing the inhibition of IL-1β, IL-6 and TNF- α production in LPS-induced BV-2 cells by Compound I and Compound II prepared in example 1 of the present invention.

Detailed Description

In order to make the technical solutions of the present invention more apparent to those skilled in the art, the following examples will be presented. It should be noted that the following examples do not limit the scope of the invention.

The starting materials, reagents or apparatus used in the following examples are all available from conventional commercial sources or may be obtained by methods known in the art unless otherwise specified.

Isolation, purification and characterization of the fungus Alternaria sp.J 030:

the fungus Alternaria sp.J030 is obtained by separating and purifying fresh leaves of plant samples Bai Huayang cercis (Bauhinia variegata Linn. Var. Candida (Roxb.) Voigt) collected from southern campus of Zhongshan university in China in 10 months in 2021, and the strain is identified as Alternaria sp.J030 GenBank by blast comparison through ITS sequence analysis, and the gene accession number is: OM062590. ITS sequences of the strain Alternaria sp. Are shown in SEQ ID NO: 1.

PDA slant culture medium used in the invention is prepared by the following method (per liter): peeling fresh potato 200g, cutting, boiling for 30min, filtering with 8 layers of gauze, adding glucose 20g and agar 20g, adding distilled water to volume to 1L, naturally adjusting pH, and sterilizing at 121deg.C for 30min. After sterilization kanamycin sulfate was added to a final working concentration of 50. Mu.g/mL.

The rice culture medium used in the invention is prepared by the following method: 300g rice and 350mL double distilled water are added in each portion, the natural pH is that the sterilization is carried out for 30min at 121 ℃.

Example 1

Polyketides I and II have the molecular structures shown below:

the preparation method of the polyketone compound comprises the following steps:

(1) Collecting strain Alternaria sp.J030 preserved in PDA slant culture medium at 4deg.C, picking strain onto PDA plate, and activating at 28deg.C for 5 days;

(2) Inoculating activated strain on a large number of PDA plates, placing in a 28 ℃ incubator for 5 days, cutting each plate full of strain (90 mm i.d.) into uniform small pieces, inoculating into a solid rice fermentation medium, uniformly stirring the bacterial pieces and rice, and standing at room temperature for 30 days to obtain a fermentation culture;

(3) Extracting the fermentation culture with ethyl acetate for 3 times, mixing the 3 times of extracting solutions, and concentrating the extracting solutions under reduced pressure to obtain ethyl acetate crude extract; firstly, carrying out silica gel column chromatography on the ethyl acetate crude extract by adopting a petroleum ether/ethyl acetate (80:1-0:1, V/V) elution system, collecting a component Fr.8 with the volume ratio of petroleum ether to ethyl acetate of 5:1-1:1, and separating the component Fr.8 by a Sephadex LH-20 (MeOH) column to obtain 5 subfractions Fr.8.1-8.5; subjecting the subfraction Fr.8.3 to silica gel column chromatography(mobile phase dichloromethane/methanol, volume ratio 50:1-5:1) to obtain subcomponent Fr.8.3a-Fr.8.3e; component Fr.8.3b was purified by semi-preparative RP-HPLC (column RP-C ₁₈ 5. Mu. Mol/L, 250X 10mm,Welch Materials,Inc.) in a volume ratio of methanol/water of 65:35 in a flow rate of 3mL/min to obtain two polyketides, compound I (retention time t _R 19.5 min) and compound II (retention time t _R 13.2 min).

Structural analysis is carried out on the compound I and the compound II, and the obtained physicochemical property data are as follows:

compound i: colorless crystals; M.P.159.5-161.2 ℃; as shown in fig. 8, UV (MeOH) lambda _max (log ε) 213 (1.56), 279 (0.65) nm; as shown in FIG. 7, IR v _max 3260,3062,2938,2433,1656,1591,1452,1421,1362,1169,1098,738,700cm ^–1 ； ¹ H NMR(Acetone-d ₆ 600 MHz) and ¹³ C NMR(Acetone-d ₆ 150 MHz) results are shown in fig. 1 and 2; as shown in FIG. 6, HRESIMS [ M-H ]] ^- m/z 331.1334(calcd.for C ₂₂ H ₁₉ O ₃ ^- 331.1334 Compound I ¹ H– ¹ The results of the H COSY spectrum, the HSQC spectrum and the HMBC spectrum are respectively shown in figures 3-5, and the results show that the compound I prepared by the invention is a polyketone compound with a molecular structure shown in the formula (I).

Compound II: colorless crystals; M.P.152.7-153.9 ℃; as shown in fig. 16, UV (MeOH) lambda _max (log ε) 211 (0.50), 260 (0.06), 315 (0.04) nm; as shown in FIG. 15, IR v _max 3204,3084,3030,2929,2874,1660,1609,1584,1452,1426,1312,1177,1050,725,696cm ^–1 ； ¹ H NMR(Acetone-d ₆ 600 MHz) and ¹³ C NMR(Acetone-d ₆ 150 MHz) results are shown in fig. 9 and 10; as shown in FIG. 14, HRESIMS [ M-H ]] ^- m/z 331.1333(calcd.for C ₂₂ H ₁₉ O ₃ ^- 331.1334 Compound II ¹ H– ¹ The results of the H COSY spectrum, the HSQC spectrum and the HMBC spectrum are respectively shown in figures 11-13, and all the results show that the compound II prepared by the invention is a polymer with a molecular structure shown in the formula (I)A ketone compound. Wherein Fragmentor Voltage in fig. 6 and 14 is the fragmentation voltage, collision Energy is the Collision Energy, ionization Mode is the Ionization Mode, ESI is the ion spray, scan (1.844 min) represents the Scan time (1.884 min), counts vs. mass-to-Charge (m/z) represents the count by mass-to-Charge ratio (m/z). In fig. 7 and 15, wavenumber is Wavenumber, and transmissibility is transmissivity.

Application example 1

An anti-inflammatory agent comprising the compound i prepared in example 1 as an active ingredient.

Application example 2

An anti-inflammatory agent comprising the compound II prepared in example 1 as an active ingredient.

Application example 3

An anti-inflammatory agent comprising the compound I and the compound II obtained in example 1 as active ingredients.

Anti-inflammatory Activity test of polyketides I and II

1. Experimental materials

The main instrument is as follows: infinite M200 Pro multifunctional microplate reader (TECAN, USA), multiskan GO full-wavelength microplate reader (Thermo Scientific, USA), amersham imager (GE, USA).

The main reagent comprises: minocycline (Mino), dimethyl sulfoxide (DMSO), fetal bovine serum, DMEM medium, lipopolysaccharide (LPS), and thiazole blue (MTT).

Test cells: BV-2 microglia.

2. Test method

2.1 cell culture

BV-2 microglial cells were added to DMEM medium containing 10% (V/V) fetal bovine serum and antibiotics (100U/mL penicillin and 100U/mL streptomycin) and incubated in an incubator (37 ℃,5% CO) ₂ ) Is cultured.

2.2 Determination of cell viability of Compounds I and II by MTT method

BV-2 cells were seeded in 96-well plates (3X 10 ³ Per well), then BV-2 microglia were pretreated with compounds I and II to be tested (20. Mu. Mol/L) for 1 hour, then incubated with LPS (1. Mu.g/mL) for 24 hours. The medium is then replaced to the endMTT at a concentration of 1mg/mL was freshly cultured in 100. Mu.L and allowed to stand in an incubator for 4 hours. The MTT solution was removed and 100 μl DMSO was added to dissolve the MTT formazan. After incubation at 37 ℃ for 10 minutes, cell viability was detected by measuring absorbance at 570 nm. The absorbance of formazan formed in control (untreated) cells is believed to represent 100% viability. Minocycline (30. Mu. Mol/L) was selected as a positive drug using 1% DMSO as a control.

2.3 Testing of NO production inhibition

iNOS activity was determined using the amount of nitrite produced (stable end product of NO oxidation). The concentration of nitrite in the medium was determined using the Griess method. BV-2 cells were pretreated with compounds I, II at concentrations of 5, 10 and 20. Mu.M, respectively, for 1 hour, followed by incubation with LPS (1. Mu.g/mL) for 24 hours. Minocycline was selected as a positive drug using 1% dmso as a control group. The results are shown in FIG. 17. An aliquot (50 μl) of each supernatant was left with an equal amount of Griess reagent at room temperature for about 10 minutes. The absorbance of the final product was spectrophotometrically measured at 540nm using an enzyme-labeled instrument. The nitrite content of the samples was evaluated using nitrite and sodium nitrate standard curves generated in DMEM medium. This test was independently repeated 3 times. And calculate its IC ₅₀ Values.

The inhibition of NO production by the drug was calculated using the following formula:

inhibition of NO production by drug (%) = (1-sample group) _{OD value} Control group _{OD value} ) X 100%. Wherein OD value is absorbance of the test object.

2.4 enzyme-Linked immunosorbent assay (ELISA)

BV-2 microglia were seeded in 24-well plates, pretreated with compounds I, II at 5, 10 and 20. Mu. Mol/L concentrations for 1 hour, and then incubated with LPS (1. Mu.g/mL) for 24 hours. The medium was collected and centrifuged at 12000rpm for 15 minutes. The amounts of the pro-inflammatory cytokines IL-6, IL-1. Beta. And TNF-. Alpha.were then determined at 450nm by ELISA using ELISA kit (Nanjing institute of biological engineering). Minocycline (30. Mu. Mol/L) was selected as a positive drug using 1% DMSO as a control. Data are expressed as mean ± Standard Deviation (SD). * P <0.05, p <0.01, p <0.001, p <0.0001, compared to the LPS group; # denotes p <0.05, # denotes p <0.01, # denotes p <0.0001, compared to the normal control group.

3. Test results

The results of the MTT assay for cell viability of compounds i and ii are shown in fig. 17, which shows that there is no significant decrease in cell viability (greater than 75% in both treatment groups) compared to the blank group, where data are expressed as mean ± SD, p <0.05, p <0.01, p <0.001, p <0.0001, compared to the LPS group; compared to the control group, #p <0.05, #p <0.01.Con: blank, LPS: LPS builds the module, mino: minocycline positive drug group, C1: compound i, C2: a compound II. It is clear that the compounds I and II have no obvious cytotoxicity on BV-2 microglial cells induced by LPS at the concentration of 20 mu mol/L, and do not influence the cell viability of the activated BV-2. Wherein Cell availability in the figure: cell viability, con: blank, LPS: LPS builds the module, mino: minocycline positive drug group, C1: compound i, C2: a compound II.

The results of the inhibition of LPS-induced NO production by Compounds I and II are shown in FIG. 18, and it is apparent from the graph that the production rate of LPS-induced NO in BV-2 cells is lower than that of minocycline, which is a positive drug, at 10. Mu.M and 5. Mu.M, and that the production rate of LPS-induced NO in BV-2 cells is lower than that of minocycline, which is a positive drug, at 5. Mu.M, whereby it is seen that Compounds I and II have anti-inflammatory activity for inhibiting the production of inflammatory factor NO. Further IC for inhibiting the production of inflammatory factor NO by Compounds I and II ₅₀ Value test, IC ₅₀ The values were 3.18.+ -. 0.21. Mu.M, 4.89.+ -. 0.27. Mu.M, respectively, and their ICs ₅₀ All lower than 10. Mu.M, indicating that compounds I and II have potent anti-inflammatory activity. In the figure, NO production: NO yield, con: blank, LPS: LPS builds the module, mino: minocycline positive drug group, 1: compound i, 2: a compound II.

FIG. 19 (a) shows the inhibition of IL-1β production by Compound I and Compound II in LPS-induced BV-2 cells, FIG. 19 (b) shows the inhibition of IL-6 production by Compound I and Compound II in LPS-induced BV-2 cells, and FIG. 19 (c) shows the inhibition of TNF- α production by Compound I and Compound II in LPS-induced BV-2 cells, as can be seen from FIGS. 19 (a), (b) and (c), compounds I and II significantly inhibit the production of inflammatory factors IL-1β, IL-6 and TNF- α in LPS (1. Mu.g/mL) induced BV-2 microglia at concentrations of 5. Mu.mol/L, 10. Mu.mol/L and 20. Mu.mol/L; the inhibition effect of the compound I on inflammatory factors IL-1 beta, IL-6 and TNF-alpha is better than that of a positive drug minocycline (30 mu mol/L) at the concentration of 10 mu mol/L and 20 mu mol/L; the inhibition effect of the compound II on inflammatory factor IL-1 beta is better than that of the positive medicine minocycline (30 mu mol/L) at the concentration of 5 mu mol/L, 10 mu mol/L and 20 mu mol/L, and the inhibition effect of the compound II on inflammatory factor TNF-alpha is better than that of the positive medicine minocycline (30 mu mol/L) at the concentration of 20 mu mol/L. From the above results, it is clear that compounds I and II are capable of significantly inhibiting the expression levels of inflammatory factors IL-6, IL-1. Beta. And TNF-. Alpha.in the cells. In the figure, con is a blank control, LPS is lipopolysaccharide, mino is minocycline, C1 is a compound I with different concentrations, C2 is a compound II with different concentrations, and uM is mu mol/L. Therefore, the invention provides candidate compounds for researching and developing new anti-inflammatory drugs and provides new resources and ways for producing anti-inflammatory drugs.

SEQUENCE LISTING

<110> university of Zhongshan

<120> a polyketone compound of fungal origin, and preparation method and application thereof

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<160> 1

<170> PatentIn version 3.5

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<211> 547

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<213> Alternaria sp. J030

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Claims (9)

1. The polyketide is characterized by having a molecular structure shown in the following formula (I):

R ₁ and R is ₂ Each independently selected from H or benzyl, R ₁ And R is ₂ Not both H and benzyl.

2. The process for preparing polyketides according to claim 1, wherein the polyketides are isolated from a fermentation culture of the endophytic fungus Alternaria sp.J030, which strain Alternaria sp.J030 has been deposited at the microorganism seed culture Collection, guangdong province, address: guangzhou city first middle road No. 100 college No. 59 building, date of preservation: 2022, 4, 28, deposit number: GDMCC No:62440;

the preparation method of the polyketone compound comprises the following steps:

(1) Activating the endophytic fungus Alternaria sp.J030;

(2) Fermenting and culturing the plant endophytic fungi Alternaria sp.J030 after the activation in the step (1) to obtain a fermentation culture;

(3) Extracting the fermentation culture in the step (2) to obtain a crude extract, and separating and purifying to obtain the polyketide with the molecular structure shown in the formula (I).

3. The method according to claim 2, wherein in the step (1), the activation is carried out at a constant temperature of 25 to 30 ℃ for 3 to 7 days.

4. The method according to claim 2, wherein in the step (2), the fermentation culture is inoculated into a fermentation medium and cultured at 20 to 40℃for 20 to 40 days to obtain a fermentation culture.

5. The method according to claim 4, wherein in the step (2), the endophytic fungus Alternaria sp.J030 is inoculated onto a plate for cultivation before the step (1) is performed.

6. The method according to claim 2, wherein in the step (3), the separation is performed by eluting through silica gel column chromatography and then Sephadex LH-20 column separation.

7. The method of claim 2, wherein in step (3), the purification is performed using reversed phase C ₁₈ The column is purified by semi-preparative high performance liquid chromatography, and the mobile phase is methanol and water.

8. Use of polyketides as defined in claim 1 for the preparation of anti-inflammatory drugs.

9. An anti-inflammatory drug comprising the polyketide of claim 1 and an adjuvant.

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