CN117843703A

CN117843703A - Heptosaponin derivative, and preparation method and application thereof

Info

Publication number: CN117843703A
Application number: CN202311835140.6A
Authority: CN
Inventors: 陈义华; 王敏; 李鹏伟
Original assignee: Institute of Microbiology of CAS
Current assignee: Institute of Microbiology of CAS
Priority date: 2023-12-28
Filing date: 2023-12-28
Publication date: 2024-04-09

Abstract

The invention discloses heptosaponin derivatives, and a preparation method and application thereof. The structural formula is shown in formula I. The invention adopts a method of combining microbial fermentation with chemical semisynthesis to obtain six heptosaponin derivatives with new structures. The anti-dermatophyte activity experiment shows that the activity of the obtained 7 heptosaponin derivatives on the test strain is compared with that of the positive derivativesThe best antifungal activity was seen with fluconazole, the lowest MIC of SEPS646 for the test fungi. Next, we tested the anti-tumor activity of SEPS646, found that SEPS646 had different levels of activity in inhibiting tumor cell proliferation, SEPS646 had greater activity on tumor cells MC38 and HepG2 than 5-fluorouracil, while SEPS646 had toxicity on human normal keratinocytes comparable to 5-fluorouracil.

Description

Heptosaponin derivative, and preparation method and application thereof

Technical Field

The invention belongs to the field of biological medicine, and in particular relates to heptosaponin derivatives, and a preparation method and application thereof.

Background

Heptosaponin (Septacidin) is a class of compounds with a specific N ⁶ The glycosylated adenine core nucleoside antibiotic was isolated in 1963 from fermentation broth of Streptomyces rimosus (Streptomyce fimbriatus ATCC 15051) and has good antitumor and antifungal activity. The chemical structure of heptosaponin is mainly composed of fatty acyl side chain, glycyl, aminoheptose and adenine (shown in figure 1).

The heptosaponin has good activity of resisting dermatophyte, such as Trichophyton rubrum (Trichophyton rubrum), trichophyton mentagrophytes (Trichophyton mentagrophytes), and Microsporum canis (Microsporon canis). Studies on its antitumor activity showed that heptocin was active against mouse adenocarcinoma CA755, but not against Walker carcinoma sarcoma 256 and L1210 lympholeukemia cells, indicating that it has an unusual spectrum of anticancer activity. Furthermore, recent studies have found that heptosaponin can induce immunogenic cell death. Studies on the structure-activity relationship of heptosaponin show that the length of the fatty acyl chain is critical for the antitumor activity of the heptosaponin, and when the fatty acyl chain is shortened to hexanoyl, the antitumor activity of the heptosaponin is lost.

The fermentation of the streptomyces rimosus is unstable, and the chemical method for fully synthesizing the heptosaponin has the advantages of long steps and low yield, so that the subsequent research of the heptosaponin is seriously hindered; meanwhile, the hepcidin hepatotoxicity is serious, so that the research and development of the compounds are further limited. Therefore, the gene cluster responsible for synthesizing the heptosaponin is subjected to heterologous expression to obtain a large amount of heptosaponin which is used for chemical semisynthesis derivative, so that the anti-dermatophyte and the heptosaponin derivative with remarkably improved anti-tumor activity and reduced cytotoxicity are prepared, the potential of developing the compound into a drug lead compound is greatly improved, and the compound is expected to be advanced to preclinical researches.

Disclosure of Invention

It is an object of the present invention to provide a class of heptosaponin derivatives, septacidins.

The structural formula of the heptosaponin derivative-septacidins provided by the invention is shown as formula I:

wherein,

R ₁ selected from any one of the following groups:

(a1)H

(b1)OH

R ₂ selected from any one of the following groups:

(a2)H

(b2)OH

R ₃ selected from any one of the following groups:

when R is ₁ When a1 or b1, R ₃ Any one of a3-f 3.

When R is ₂ In the case of a2 or b2, R ₃ Any one of a3-f 3.

Preferably, the heptocin derivative-septacidins is selected from at least one of the following: SEPS646, SEPS747, SEPS727, SEPS775, SEPS717, and SEPS605, each having the following structural formula:

the heptocin derivatives represented by the formula I, namely the pharmaceutically acceptable salts, esters and prodrugs of the septacidines, also belong to the protection scope of the invention.

The term "pharmaceutically acceptable salt" as used herein refers to salts that are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like commensurate with a reasonable benefit/risk ratio.

The term "pharmaceutically acceptable esters" as used herein refers to esters that hydrolyze in vivo and include those that readily decompose in the human body to give the parent compound or salt thereof.

The term "pharmaceutically acceptable prodrugs" as used herein refers to those prodrugs of the compounds of the invention and the possible zwitterionic forms of the compounds of the invention which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and lower animals without excessive toxicity, irritation, allergic response, etc., commensurate with a reasonable benefit/risk ratio, and effective for their intended use. The term "prodrug" refers to a compound that can be rapidly converted in vivo, for example, by hydrolysis in blood, to yield the parent compound of the above formula.

It is another object of the present invention to provide a process for the preparation of the heptosaponin derivative-septacidins represented by formula I above.

The preparation method of the heptosaponin derivative-septacidins shown in the formula I provided by the invention comprises the following steps: 1) Streptomyces albus 1598 (described in the following: d-sedohepulose-7-phosphate is a common precursor for the heptoses of septacidin and hygromycin B.) strain, and collecting fermentation broth;

2) Centrifuging the fermentation liquor, collecting thalli and supernatant, performing wall breaking treatment on the thalli by using acetone, adding methanol for soaking, repeatedly extracting, combining the collected organic phases, and performing vacuum concentration to obtain a crude extract of heptosaponin;

separating and purifying the crude extract obtained in the step 2) by using a silica gel column chromatography, wherein the eluent of the silica gel column chromatography is as follows: ethyl acetate with the volume of 1 time of the column volume, mixed solution of ethyl acetate and methanol with the volume ratio of 1:1 with the volume of 1.5-2 times of the column volume and methanol with the volume ratio of 1:1 with the volume ratio of 1-5 times of the column volume are collected, eluted components eluted by ethyl acetate and methanol with the volume ratio of 1:1 and methanol are concentrated to obtain a concentrate;

3) Dissolving the crude separation product (concentrate) in methanol, adding inorganic acid into the methanol, carrying out acid hydrolysis at 50-100 ℃, spin-drying the solvent, and separating and purifying the concentrated solution through a reversed-phase C18 packing column to obtain a pure SEP384 product;

wherein, the eluent of the C18 packed column chromatography is as follows in sequence: 1-1.5-2 times of water, 1.5-1.5 times of methanol-water volume ratio 3:97 mixed solution, 1-1.5 times of methanol-water volume ratio 5:95 mixed solution, 1-1.5 times of methanol-water volume ratio 10:90 mixed solution, 1-1.5 times of methanol-water volume ratio 50:50 mixed solution, 1-1.5 times of methanol, collecting eluting components eluted by the methanol-water volume ratio 3:97 mixed solution, concentrating, and taking the obtained hydrolyzed product SEP384 as a raw material for preparing other heptectin derivatives for freezing storage for standby;

4) For the preparation of the target product SEPS646, the specific preparation method involved is as follows:

linoleic acid (0.1 g) was dissolved in N, N-Dimethylformamide (DMF) (10 mL), p-nitrophenol (0.08 g) and Dicyclohexylcarbodiimide (DCC) (0.1 g) were added thereto, the reaction was stirred at room temperature for 12 hours until the reaction was completed, the mixture was filtered, the product SEP384 (0.05 g) after hydrolysis in the above step (3) and triethylamine (0.15 mL) were added to the filtrate, the mixture was reacted at room temperature for 12 hours, the reaction solution was lyophilized after the reaction was completed, the lyophilized product was separated by HPLC, acetonitrile and water containing 0.01% by mass of trifluoroacetic acid were used as mobile phases, the acetonitrile and water containing 0.01% by mass of trifluoroacetic acid were eluted in an equiconcentration gradient at a volume ratio of 35:65, and the target peak SEPS was collected 646 to obtain the compound SEPS646.

For the preparation of SEPS747, SEPS727, SEPS775, SEPS717, SEPS605, the specific preparation methods involved are as follows:

linoleic acid, arachidonic acid or 10-undecylenic acid (0.1 g) are dissolved in Dichloromethane (DCM) (2 mL), oxalyl chloride (0.1 g) and DMF (20 mL) are added into the solution, the reaction is carried out for 3 hours at room temperature, the reaction solution is dried in a spinning way, and the obtained oily compound (linolic acid chloride, arachidonic acid chloride or 10-undecylenoyl chloride) is directly used for the next reaction without purification;

glycine, beta-alanine, threonine or aspartic acid (0.05 g) is dissolved in aqueous solution of sodium hydroxide (NaOH) (0.2 g), to which oily compound (0.1 g), arachidonic acid chloride or 10-undecanoyl chloride (0.1 g) obtained in the previous step is added, the mixture is reacted overnight at room temperature, after the reaction is finished, the pH of the solution is adjusted to 3 with concentrated hydrochloric acid, the precipitate produced is collected, and the precipitate is washed with water and diethyl ether to obtain linoleoyl-glycine, arachidonic acid-glycine, linoleoyl-beta-alanine, linoleoyl-threonine, linoleoyl-aspartic acid or 10-undecanoyl-glycine;

dissolving the product (0.1 g) obtained in the last step in DMF (3 mL), adding N-hydroxysuccinimide (N-hydroxysuccinimide 0.04 g) and DCC (0.07 g) into the solution, reacting for 12 hours at room temperature, filtering the reaction solution after the reaction is finished, adding the product SEP384 (25 mg) obtained by hydrolyzing the step (3) and triethylamine (0.3 mL) into the filtrate, reacting the mixture for 24 hours at room temperature, freeze-drying the solution after the reaction is finished, and purifying by HPLC to prepare the product;

acetonitrile and water containing 0.01 percent of trifluoroacetic acid by mass fraction are taken as mobile phases, the acetonitrile and the water containing 0.01 percent of trifluoroacetic acid by mass fraction are subjected to equal concentration gradient elution according to a volume ratio of 35:65, and target peaks SEPS747, SEPS727, SEPS775, SEPS717 and SEPS605 are collected.

In the above method step 1), the fermentation culture is performed in a liquid medium, which is a GPS fermentation medium. The composition of each liter of the GPS fermentation medium is as follows: 12g of potato starch, 8g of soybean powder, 3g of yeast extract, 10mL of 0.05% cobalt chloride hexahydrate, 2.5g of calcium carbonate and adjusting the pH to 7.2 by sodium hydroxide.

The inoculum size of the Streptomyces albus 1598 was 6%.

The Streptomyces albus 1598 strain also comprises the step of preparing Streptomyces albus 1598 seed liquid before inoculation, and the method specifically comprises the following steps: inoculating spores of Streptomyces albus 1598 strain to GYT seed solution culture medium, and culturing at 28 ℃ for 48h;

wherein, the GYT seed culture medium comprises the following components/L: yeast extract 10g, peptone 10g,0.05% cobalt chloride hexahydrate 10mL, calcium carbonate 2.5g, sodium hydroxide to adjust pH to 7.2. The GYT seed culture medium is also added with the aminoplast, and 25 mu l of the aminoplast is added into each 50ml of GYT seed culture medium.

In the above method step 3), the inorganic acid may be hydrochloric acid, dilute sulfuric acid, dilute nitric acid, or the like.

When the inorganic acid is hydrochloric acid, the concentration of the hydrochloric acid is 1M.

The temperature of the acid hydrolysis may be 50-100 ℃, and the time of the acid hydrolysis may be 1-3 hours.

In the above method step 3), the chromatographic conditions of the reverse phase high performance liquid chromatography are as follows: the chromatographic column is Aglient SB-CN Semi-preparative, with the specification of 9.4X105 mm and 5 μm; the flow rate was 2mL/min.

A further object of the present invention is to protect the heptocin derivative of formula I, septacidins, for pharmaceutical use.

The application of the heptocin derivative-septacidins shown in the formula I provided by the invention in the aspect of medicine comprises the following aspects: 1) The application in preparing antifungal medicine; 2) The application in preparing antitumor drugs.

The antifungal medicine is an anti-dermatophyte medicine.

Further, the dermatophytes are trichophyton rubrum (Trichophyton rubrum), trichophyton mentagrophytes (Trichophyton mentagrophytes), epidermophyton floccosum (Epidermophyton floccosum), microsporopsis canis (Microsporum canis) and the like, and the dermatophytes are not limited to the above specific species.

Further, the dermatophyte-resistant medicament is used for preventing and/or treating dermatophyte infection caused by trichophyton rubrum, trichophyton mentagrophytes, epidermophyton floccosum, microsporium canis and the like.

The antitumor drug is an anti-liver cancer or anti-colon cancer drug.

The tumor is liver cancer or colon cancer.

The invention also protects an anti-dermatophyte or anti-tumor drug.

The active ingredients of the anti-dermatophyte or anti-tumor medicine comprise heptosaponin derivatives-septacidins shown in the formula I.

The active ingredients of the dermatophyte resisting medicine can also comprise other antifungal medicines.

The active ingredients of the antitumor drug can also comprise other antitumor drugs.

The heptocin derivative shown in the formula I can be used for preventing and/or treating inflammation and infection caused by skin fungi with resistance to azoles, allylamines, thiocarbamates, morpholines, hydroxamic acids, pyrimidines, polyenes, echinocandins and the like, alone or in combination with other antifungal agents.

The medicament may further comprise pharmaceutically acceptable diluents, excipients, fillers, binders, wetting agents, disintegrants, absorption enhancers, surfactants, adsorption carriers, lubricants, synergists, additives, solvents, and the like. In the preparation of the dermatophyte resistant medicament, an effective dose of the compound can be mixed with pharmaceutically acceptable diluents, excipients, fillers, adhesives, wetting agents, disintegrants, absorption promoters, surfactants, adsorption carriers, lubricants, synergists, additives, solvents and the like to prepare various medicinal preparations. The medicine can be in the form of tablet, capsule, soft capsule, powder, granule, fine granule, liquid, pill, emulsion or suspension, etc., or can be non-oral preparation such as injection (such as powder, water agent, oil agent) suppository, ointment, plaster, patch, spray, tincture or eye drop, etc. These formulations are obtained by methods well known to those skilled in the art. The administration route can be oral, percutaneous, intravenous or intramuscular injection.

The heptosaponin is composed of four parts of aminoheptose, adenine, glycyl and fatty acyl, and has biological activity of resisting dermatophytes and tumors. Wherein the length of the fatty acyl chain of heptosaponin is critical for its anti-dermatophyte and anti-tumor activity, which is lost when the fatty acyl chain is shortened to caproyl. By modifying the fatty acyl group of heptosaponin, it is possible to obtain heptosaponin analogues of various new structures.

The invention utilizes a method of biologically fermenting and producing a mother nucleus structural unit and adding organic chemical derivative to carry out structural transformation on a side chain fatty acyl group of heptosaponin to obtain new structural compounds SEPS646, SEPS747, SEPS727, SEPS775, SEPS717 and SEPS605. The anti-dermatophyte activity experiments show that the Minimum Inhibitory Concentration (MIC) of SEPS646, SEPS747, SEPS727, SEPS775, SEPS717 and SEPS605 on trichophyton rubrum, trichophyton mentagrophytes, epidermophyton floccosum and microsporum canis is lower than that of the prior medicine fluconazole. Therefore, by reasonably modifying the fatty acyl side chain, the heptosaponin derivative with good anti-dermatophyte activity is obtained.

The invention aims to modify the structure of heptosaponin to obtain a compound with higher anti-dermatophyte activity than the prior drug fluconazole. The invention has the advantages that: sufficient heptosaponin mother nucleus structure for subsequent chemical modification is obtained through biological fermentation, and chemical semisynthesis derivatization is carried out on the mother nucleus structure to obtain the heptosaponin derivative with good anti-dermatophyte activity.

Six new structure heptosaponin derivatives are obtained by chemical semisynthetic derivatization of the acid hydrolysis product of heptosaponin. The anti-dermatophyte activity experiments show that the Minimum Inhibitory Concentration (MIC) of SEPS646, SEPS747, SEPS727, SEPS775, SEPS717 and SEPS605 on trichophyton rubrum, trichophyton mentagrophytes, epidermophyton floccosum and microsporum canis is lower than that of the prior medicine fluconazole. The anti-tumor activity experiment shows that the activity of SEPS646 against liver cancer and colon cancer is higher than that of the existing medicine 5-fluorouracil. The method avoids the production of heptosaponin derivatives by a chemical total synthesis method, simplifies the lengthy synthesis steps of the chemical total synthesis, avoids a plurality of toxic reagents used in the total synthesis, and provides a good material basis for the subsequent development of the compounds into clinically used medicaments.

Drawings

FIG. 1 is a structural formula of septacidins and analogs thereof;

FIG. 2 shows the process of example 1Prepared SEPS646 ¹ H NMR spectrum;

FIG. 3 is a SEPS747 prepared in example 2 ¹ H NMR spectrum;

FIG. 4 is a SEPS727 prepared in example 2 ¹ H NMR spectrum;

FIG. 5 shows SEPS775 prepared in example 2 ¹ H NMR spectrum;

FIG. 6 is a SEPS717 prepared in example 2 ¹ H NMR spectrum;

FIG. 7 is a SEPS605 prepared in example 2 ¹ H NMR spectrum;

FIG. 8 is a toxicity test of SEPS646 on MC38 cells. 5-FU: 5-fluorouracil at a concentration of 10 μg/mL;

FIG. 9 is a toxicity test of SEPS646 on Hacat cells. 5-FU: 5-fluorouracil at a concentration of 10 μg/mL;

FIG. 10 is a toxicity test of SEPS646 on HepG2 cells. 5-FU: 5-fluorouracil at a concentration of 10. Mu.g/mL.

Detailed Description

The process of the present invention is illustrated by the following examples, but the invention is not limited thereto, and any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention should be included within the scope of the present invention.

The experimental methods used in the following examples are conventional methods unless otherwise specified.

Materials, reagents and the like used in the examples described below are commercially available unless otherwise specified.

Streptomyces albus 1598 (described in the following document: D-sedohepulose-7-phosphate is a common precursor for the heptoses of septacidin and hygromycin B.) used in the examples described below is available to the public from the applicant and can only be used for repeating the experiments of the present invention.

Example 1

Preparation method of SEPS 646:

1) Fermentation of heptosaponin

Spores of the high-yield strain Streptomyces albus 1598 frozen in a refrigerator at-80℃were spread on MS solid medium with a cotton swab, and cultured in a constant temperature incubator at 28℃for 7 days. Spores on the plates were scraped into GYT medium (apramycin, 25. Mu.l/50 ml) with a cotton swab and the seed solution was shaken at a constant temperature of 28℃for 2 days on a shaker at 220 rpm. Transferring to GPS culture medium (no antibiotics are added to seed solution of 3ml per 50 ml), and fermenting for 5-6 days. And (3) centrifuging at 5000rpm/min for 20min to collect thalli, breaking the walls of the thalli by acetone, and soaking the thalli in methanol for 1 day. The thalli are further soaked in methanol, the extraction is repeated, the collected organic phases are combined, and the concentrated solution is in vacuum to obtain the crude product of heptosaponin.

Wherein, GYT seed solution culture medium: 10g/L of yeast extract, 10g/L of peptone, 10mL/L of 0.05% cobalt chloride hexahydrate, 2.5g/L of calcium carbonate and pH 7.2.

GPS medium: 12g/L of potato starch, 8g/L of soybean powder, 3g/L of yeast extract, 10mL/L of 0.05% cobalt chloride hexahydrate, 2.5g/L of calcium carbonate and pH 7.2.

2) Preparation of SEPS646

Reagents and conditions: (a) 1M HCl/MeOH,50 ℃ for 1h; (b) p-Nitrophenol, DMF, DCC,12h; (c) SEP384, et ₃ N，DMF，24h。

The first step: separating and purifying the crude product of the heptosaponin in the step 1) by using a silica gel column chromatography, wherein the eluent of the silica gel column chromatography is as follows: ethyl acetate with the volume of 1 time of the column volume, mixed solution of ethyl acetate and methanol with the volume ratio of 1:1 with the volume of 1.5-2 times of the column volume and methanol with the volume ratio of 1:1 with the volume ratio of 1-5 times of the column volume are collected, eluted components eluted by ethyl acetate and methanol with the volume ratio of 1:1 and methanol are concentrated to obtain a concentrate;

and a second step of: dissolving the crude product of heptosaponin collected by concentrate fermentation in 1M hydrochloric acid methanol solution, carrying out acid hydrolysis for 1 hour at 50 ℃, spin-drying the solvent, and separating and purifying the concentrated solution by a reversed-phase C18 packed column to obtain purified SEP384. Wherein, the eluent of the C18 packed column chromatography is as follows in sequence: 1 time of water, 1.5-2 times of mixed solution of methanol and water in a volume ratio of 3:97, 1-1.5 times of mixed solution of methanol and water in a volume ratio of 5:95, 1-1.5 times of mixed solution of methanol and water in a volume ratio of 10:90, 1-1.5 times of mixed solution of methanol and water in a volume ratio of 50:50, 1-1.5 times of methanol, collecting eluting components eluted by the mixed solution of methanol and water in a volume ratio of 3:97, concentrating, and taking the obtained hydrolyzed product SEP384 as a raw material for preparing other heptectin derivatives for freezing storage for standby.

Compound 1 (linoleic acid, 0.1 g) and p-nitrophenol (0.08 g) were dissolved in 10mL of DMF, DCC (0.1 g) was added to the mixture, the mixture was stirred at room temperature for reaction for 12 hours, the mixture was filtered after the reaction was completed, SEP384 (50 mg) and triethylamine (0.15 mL) were added to the filtrate, the mixture was reacted at room temperature for 24 hours, the reaction solution was lyophilized, the lyophilized product was separated by HPLC, acetonitrile, water containing 0.01% by mass of trifluoroacetic acid as a mobile phase, and the acetonitrile, water containing 0.01% by mass of trifluoroacetic acid were eluted in an isoconcentration gradient at a volume ratio of 35:65, and the target peak SEPs646 was collected to obtain compound SEPs646.SEPS646 ¹ The H NMR spectrum is shown in FIG. 2.

Example 2

The preparation method of the SEPS747 comprises the following steps:

1) The fermentation of heptosaponin was the same as in example 1.

2) Preparation of SEPS747

Reagents and conditions: (a) Oxalyl chloride, DMF, DCM,3h; (b) threonine (threonine), naOH,12h; (c) DCC, N-hydroxysuccinimide (N-hydroxysuccinimide), DMF; (d) SEP384, et ₃ N,DMF,24h.

In the first step, compound 1 (linoleic acid, 0.1 g) was dissolved in methylene chloride (2 mL), oxalyl chloride (0.09 g) was added thereto, then a catalyst amount of DMF (3 drops) was added to the mixture, the reaction was stirred at room temperature, after the gas generated by the reaction stopped (about 30 min), the mixture was continued to be stirred at room temperature for 2.5 hours, and after the reaction was completed, the reaction solution was dried by spinning, and the obtained oily compound 3 (linoleate chloride) was directly used for the next reaction without purification.

In the second step, threonine (0.05 g) was dissolved in an aqueous NaOH (0.2 g), to which was added compound 3 (0.1 g) obtained in the previous step, and the mixture was reacted at room temperature overnight, after the reaction was completed, the pH of the solution was adjusted to 3 with concentrated hydrochloric acid, and the resulting precipitate was collected and washed with water and diethyl ether to obtain compound 4.

Third, compound 4 (0.1 g) was dissolved in DMF (3 mL), N-hydroxycicinimide (0.04 g) and DCC (0.07 g) were added thereto, and after the reaction was completed, the reaction solution was filtered and the filtrate was freeze-dried to obtain Compound 5.

Fourth, compound 5 is dissolved in DMF (3 mL), SEP384 (25 mg) and triethylamine (0.3 mL) are added to the mixture, the mixture is reacted for 24 hours at room temperature, after the reaction is finished, the solution is freeze-dried and HPLC is purified, acetonitrile and water containing 0.01 percent by mass of trifluoroacetic acid are taken as mobile phases, the acetonitrile and the water containing 0.01 percent by mass of trifluoroacetic acid are subjected to equal concentration gradient elution according to a volume ratio of 35:65, and a target peak SEPS747 is collected to obtain the compound SEPS747.

The preparation method of the SEPS775 comprises the following steps: the process is similar to that of SEPS747 except that aspartic acid is used in the second step as a substitute for threonine in the SEPS747 process.

The preparation method of the SEPS717 comprises the following steps: the process is similar to that of SEPS747 except that beta-alanine is used as a threonine alternative in the SEPS747 process in the second step.

The preparation method of the SEPS727 comprises the following steps: the process is similar to that of SEPS747 except that in the first step arachidonic acid is used as a substitute for compound 1 (linoleic acid) in the SEPS747 process.

Preparation method of SEPS 605: the process is similar to that of SEPS747 except that 10-undecylenic acid is used in the first step as an alternative to compound 1 (linoleic acid) in the process of SEPS747.

The structural formula, NMR and MS data of the partially preferred compounds of the invention prepared as described above are detailed in table 1 below:

TABLE 1 structural formulas and NMR and MS data for preferred Compounds of the invention

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The above compounds have activity against dermatophytes.

Effect examples

1. In vitro anti-dermatophyte activity test

The heptocin derivatives SEPS646, SEPS747, SEPS727, SEPS775, SEPS717 and SEPS605 prepared by the method are used for carrying out in-vitro dermatophyte resistance activity experiments, and the positive control is fluconazole. The test strains were Trichophyton rubrum (Trichophyton rubrum ATCC 28188), trichophyton mentagrophytes (Trichophyton mentagrophytes ATCC 18748), epidermophyton floccosum (Epidermophyton floccosum ATCC 9646), and Microsporum canis (Microsporum canis ATCC 32903).

Materials and instruments: constant temperature incubator (SPX-250B-Z Shanghai Bo Xuan medical equipment works); bench-top constant temperature oscillator (DDHZ-300 Suzhou Pegyin laboratory Co., ltd.); medical multifunctional ultra clean bench (Beijing Tong Harr instruments Co., ltd.); high pressure steam sterilizing pot (Shanghai Boqun medical equipment factory); 96-well cell culture plates (corning life sciences limited); synergy H4 Hybrid reader (Bio Tek, germany).

Preparation of antifungal drug: weighing a proper amount of heptosaponin derivative and positive control antifungal drug fluconazole, dissolving with minimum DMSO, diluting with deionized water to a final concentration of 100mM (DMSO concentration not exceeding 5%), and storing at-80deg.C.

Preparation of fungus inoculation liquid: the test fungi were inoculated into Potato Dextrose Agar (PDA) medium and activated for 10 days at 29 ℃. Then, 1mL of sterile 0.85% saline containing 0.1% Tween 80 was added dropwise to the lawn, and the colonies to be tested were gently pipetted with a sterile pipette tip to prepare a suspension. Transferring the suspension into a sterile tube, standing for 5min, taking the upper homogeneous liquid into the sterile tube, swirling for 15s, filtering the bacterial suspension with a spore filter, and measuring the OD value of about 0.15 with an enzyme-labeled instrument at the wavelength of 490 nm.

Preparing a drug sensitive plate: 200. Mu.L of the previously prepared heptosaponin and fluconazole 250. Mu.M solution were aspirated, and the resulting solution was added to a 96-well plate, and 1 to 9 wells were diluted to nine concentrations of 62.5. Mu.M, 31.25. Mu.M, 15.62. Mu.M, 7.81. Mu.M, 3.90. Mu.M, 1.95. Mu.M, 0.98. Mu.M, 0.49. Mu.M, and 0.24. Mu.M, respectively, by a double dilution method, with 100. Mu.L of sterile water being added to the 10 th well, 100. Mu.L of DMSO (concentration. Ltoreq.1%) being added to the 11 th well, and 100. Mu.L of sterile water being added to the 12 th well.

Inoculation of liquid medium: diluting the fungus suspension mother liquor prepared before with RPMI-1640 culture medium for 50 times to obtain fungus suspension (1×10) with 2 times of required experimental concentration ³ ～3×10 ³ ). On the prepared 96 Kong Yaomin plates, 100. Mu.L of diluted fungal suspension was added to 1-9, 11 and 12 wells, respectively, using a pipette. As a negative control, 100. Mu.L of RPMI-1640 medium was added to well 10. The results of the experiment were observed after 96 hours at a constant temperature of 29℃and are shown in Table 2.

TABLE 2 anti-dermatophyte Activity of heptocin derivatives

From the data in table 2 above, the compounds SEPS646, SEPS747, SEPS727, SEPS775, SEPS717 and SEPS605 have antifungal activity against skin fungi, and the antifungal activity against skin fungi is higher than that of the positive control drug fluconazole, of which SEPS646 has the strongest activity.

2. In vitro anti-tumor Activity assay

In-vitro anti-tumor activity experiments are carried out by using the prepared heptosaponin derivative SEPS646, and the positive control drug is 5-fluorouracil. The cell lines tested were HaCat cells, hepG2 cells and MC38 cells. Materials and instruments: constant temperature incubator, 96 well cell culture plate (corning life sciences limited) CCK8 (bi yun tian).

Cytotoxicity experiment: the human liver cancer cell HepG2, the human immortalized keratinocyte HaCat and the mouse colon cancer cell MC328 are recovered and then are passaged to stable growth. HepG2, haCat and MC328 cells were adjusted to 5X 10 ⁴ cells/mL were added to 96-well plates at an inoculum size of 100. Mu.L/well, and incubated in a cell incubator for 6h (37 ℃ C., 5% CO) ₂ ). After cell attachment, the medium and a small portion of non-attached cells were removed and washed three times with 1 XPBS. mu.L of DMEM medium containing SEPS646 (0, 2, 4, 6, 8, 10. Mu.g/mL) was then added to each well, followed by incubation in a cell incubator for 24h. After the incubation was completed, the medium was removed and washed three times with 1 XPBS, 100. Mu.L of 1 XPBS containing 10. Mu.L of CCK8 solution was added to each well, and after incubation in a cell incubator for 1.5h, the A450 values were determined. Cell viability was calculated from the value of a 450: cell viability (%) = [ (As-Ab)/(Ac-Ab). Where As is the absorbance of the sample containing SEP622, ac is the absorbance of the sample without SEPS646, ab is the absorbance of the solution without SEPS646 (without cells), and the experimental results are shown in FIGS. 8-10.

From FIGS. 8-10, it can be seen that SEPS646 has various levels of activity in inhibiting tumor cell proliferation, that SEPS646 has greater activity on tumor cells MC38 and HepG2 than 5-fluorouracil, and that SEPS646 has comparable toxicity on human normal keratinocytes as 5-fluorouracil.

Claims

1. A compound of formula I or a pharmaceutically acceptable salt, ester or prodrug thereof:

wherein,

R ₁ selected from any one of the following groups:

(a1)H

(b1)OH

R ₂ selected from any one of the following groups:

(a2)H

(b2)OH

R ₃ selected from any one of the following groups:

(a3)

(b3)

(c3)

(e3)

(d3)

(f3)

2. the compound of claim 1, or pharmaceutically acceptable salts, esters, and prodrugs thereof, wherein: the compound is selected from at least one of the following: SEPS646, SEPS747, SEPS727, SEPS775, SEPS717, and SEPS605, each having the following structural formula:

3. a process for the preparation of a compound as claimed in claim 2 comprising the steps of:

1) Fermenting and culturing the Streptomyces albus 1598 strain, and collecting fermentation liquor;

2) Centrifuging the fermentation liquor, collecting thalli and supernatant, performing wall breaking treatment on the thalli by using acetone, adding methanol for soaking, repeatedly extracting, combining the collected organic phases, and performing vacuum concentration to obtain a crude extract of heptosaponin; separating and purifying the crude extract by using a silica gel column chromatography, wherein the eluent of the silica gel column chromatography comprises the following components in sequence: ethyl acetate with the volume of 1 time of the column volume, mixed solution of ethyl acetate and methanol with the volume ratio of 1:1 with the volume of 1.5-2 times of the column volume and methanol with the volume ratio of 1:1 with the volume ratio of 1-5 times of the column volume are collected, eluted components eluted by ethyl acetate and methanol with the volume ratio of 1:1 and methanol are concentrated to obtain a concentrate;

3) Dissolving the concentrate obtained in the step 2) in methanol, adding inorganic acid into the methanol to carry out acid hydrolysis, spin-drying the solvent, and separating and purifying the concentrate through a reversed-phase C18 packing column to obtain a SEP384 pure product;

wherein the eluent of the C18 packed column chromatography is as follows in sequence: 1-1.5-2 times of water, 1.5-1.5 times of methanol-water volume ratio 3:97 mixed solution, 1-1.5 times of methanol-water volume ratio 5:95 mixed solution, 1-1.5 times of methanol-water volume ratio 10:90 mixed solution, 1-1.5 times of methanol-water volume ratio 50:50 mixed solution, 1-1.5 times of methanol, collecting eluting components eluted by the methanol-water volume ratio 3:97 mixed solution, concentrating to obtain a hydrolyzed product SEP384 which is used as a raw material for preparing other heptectin derivatives, and freezing for later use;

4) For the preparation of the target product SEPS646, the preparation method is as follows:

dissolving linoleic acid in N, N-dimethylformamide, adding p-nitrophenol and dicyclohexylcarbodiimide into the solution, stirring the solution at room temperature for reaction for 12 hours until the reaction is finished, filtering the mixed solution, adding the product SEP384 and triethylamine obtained after the hydrolysis in the step (3) into the filtrate, reacting the mixture at room temperature for 12 hours, freeze-drying the reaction solution after the reaction is finished, separating the freeze-dried product by HPLC, taking acetonitrile and water containing 0.01% of trifluoroacetic acid by mass as mobile phases, performing isoconcentration gradient elution on the acetonitrile and the water containing 0.01% of trifluoroacetic acid by volume ratio of 35:65, and collecting a target peak SEPS646 to obtain a compound SEPS646;

in the method, the dosage ratio of the linoleic acid, the N, N-dimethylformamide, the p-nitrophenol, the dicyclohexylcarbodiimide, the SEP384 and the triethylamine is 0.1g in sequence: 10mL:0.08g:0.1g:0.05g:0.15mL;

or, for preparing the SEPS747, the SEPS727, the SEPS775, the SEPS717 and the SEPS605, the specific preparation method is as follows:

dissolving linoleic acid, arachidonic acid or 10-undecylenic acid in dichloromethane, adding oxalyl chloride and DMF into the solution, reacting at room temperature for 3 hours until the reaction is finished, spin-drying the reaction solution to obtain an oily compound which is directly used for the next reaction without purification; in the step, the dosage proportion of linoleic acid, arachidonic acid or 10-undecylenic acid, methylene dichloride, oxalyl chloride and DMF is 0.1g in sequence: 2mL:0.1g:20mL;

dissolving glycine, beta-alanine, threonine or aspartic acid in a sodium hydroxide aqueous solution, adding the oily compound obtained in the previous step, arachidonic acid chloride or 10-undecylenoyl chloride, reacting the mixture at room temperature overnight, adjusting the pH of the solution to 3 by using concentrated hydrochloric acid after the reaction is finished, collecting the generated precipitate, and washing the precipitate by using water and diethyl ether to obtain the linoleoyl-glycine, arachidonic acid-glycine, linoleoyl-beta-alanine, linoleoyl-threonine, linoleoyl-aspartic acid or 10-undecylenoyl-glycine; in the step, the dosage proportion of glycine, beta-alanine, threonine or aspartic acid, sodium hydroxide, oily compound, arachidonic acid chloride or 10-undecanoyl acid chloride is 0.05g in sequence: 0.2g:0.1g:0.1g;

dissolving the product obtained in the last step in DMF, adding N-hydroxysuccinimide and DCC (dimethyl formamide), reacting for 12 hours at room temperature, filtering the reaction liquid after the reaction is finished, adding the product SEP384 and triethylamine obtained after the hydrolysis in the step (3) into the filtrate, reacting the mixed solution for 24 hours at room temperature, freeze-drying the solution after the reaction is finished, and purifying by HPLC (high performance liquid chromatography); in the step, the dosage proportion of the product obtained in the previous step, DMF, N-hydroxysuccinimide, DCC, SEP384 and triethylamine is 0.1g in sequence: 3mL:0.04g:0.07g:25mg:0.3mL;

4. A method of preparation according to claim 3, characterized in that: in the step 1), the conditions of the fermentation culture are as follows: culturing at 28deg.C for 5-6 days;

alternatively, the inoculum size of Streptomyces albus 1598 is 6%.

5. The method according to claim 3 or 4, wherein: in the step 3), the chromatographic conditions of the reversed phase high performance liquid chromatography are as follows: the chromatographic column is Aglient Zorbax SB-C18, the specification is 9.4X105 mm,5 mu M; the flow rate was 2mL/min.

6. Use of a compound according to claim 1 or 2, or a pharmaceutically acceptable salt, ester or prodrug thereof, for: 1) The application in preparing antifungal medicine; 2) The application in preparing antitumor drugs.

7. The use according to claim 6, characterized in that: the antifungal drug is an antifungal drug for skin.

8. The use according to claim 7, characterized in that: the dermatophytes are dermatophytes;

further, the dermatophyte is at least one of the following: trichophyton rubrum (Trichophyton rubrum), trichophyton mentagrophytes (Trichophyton mentagrophytes), epidermophyton floccosum (Epidermophyton floccosum), and microsporopsis canis (Microsporum canis).

9. The use according to claim 6, characterized in that: the antitumor drug is an anti-liver cancer and/or anti-colon cancer drug.

10. A medicament comprising, as an active ingredient, a compound of claim 1 or 2 or a pharmaceutically acceptable salt, ester, and prodrug thereof;

the medicament has at least one of the following effects: 1) Antifungal; 2) Anti-tumor.