A benzamide antibacterial compound and its use in the preparation of antibacterial medicaments

Abstract

The present application relates to the technical field of pharmacy, in particular to a benzamide antibacterial compound and its use in the preparation of antibacterial drugs, the benzamide antibacterial compound has the following structure or its pharmaceutically acceptable salt: The benzamide antibacterial compound of the present application has antibacterial and antibacterial activity on S.aureus and E.coli, realizes the balanced expansion of the antibacterial spectrum, and has important antibacterial and antibacterial application value.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical technology, specifically to a benzamide-based antibacterial compound and its use in the preparation of antibacterial drugs. Background Technology

[0002] The main pathogens include Staphylococcus aureus and Escherichia coli. Staphylococcus aureus is one of the most common Gram-positive bacteria in clinical infections, frequently found on the upper respiratory tract mucosa and skin surface. It can produce enterotoxins, leading to food poisoning and is one of the most common pathogens causing food poisoning. Escherichia coli is one of the most common Gram-negative bacteria in clinical infections, usually transmitted via the fecal-oral route. Under certain conditions, it can cause infections of various local tissues and organs, such as the gastrointestinal tract and urinary tract, in various animals and humans.

[0003] In the current technology, compounds containing amide structures have become a research hotspot due to their structural diversity. Among them, some fatty amides and heterocyclic amides have been proven to have highly effective inhibitory and antibacterial effects against specific bacterial species.

[0004] For example, the compounds containing amide structures disclosed in technical solutions such as CN114712348A and CN116947678A have a MIC < 1 μg / mL against Staphylococcus aureus; when the compound in CN114712348A is used in combination with levofloxacin, the MIC against Escherichia coli is > 200 μg / mL.

[0005] The compound containing an amide structure disclosed in the patent technology solution with publication number CN113226469A exhibits extremely strong inhibitory activity against Acinetobacter baumannii.

[0006] The patent background technology published in CN108017664A mentions that sulfonamide compounds have problems with cytotoxicity and weak antibacterial activity.

[0007] These existing technological studies collectively demonstrate that innovative derivatization of compounds containing amide structures is a viable direction for drug development.

[0008] Despite significant progress in the development of compounds containing amide structures, the biological activity, particularly antibacterial activity, of other amide compounds remains uncertain. This technological gap means that it is impossible to predict whether structural modifications of amide compounds will retain their medicinal value and produce antibacterial effects. Benzamides, as an important subclass of amides, have had insufficient exploration of their antibacterial potential using current technologies. Therefore, providing a benzamide compound and confirming its activity is of great significance for expanding the chemical space of antibacterial drugs. Summary of the Invention

[0009] The benzamide antibacterial compound provided by this invention has a MIC of 64 μg / mL and an MBC of 64 μg / mL against Staphylococcus aureus, and a MIC of 64 μg / mL and an MBC of 128 μg / mL against Escherichia coli. This demonstrates that the benzamide antibacterial compound has significant antibacterial activity against Staphylococcus aureus and Escherichia coli, and has important value in antibacterial and antimicrobial drug applications.

[0010] The first object of the present invention is to provide a benzamide antibacterial compound having a structure represented by formula (Ⅰ) or a pharmaceutically acceptable salt thereof: .

[0011] According to formula (Ⅰ), the antibacterial compound of the benzamide class has the chemical name: 4-[[(1,3,3-trimethyl-2-indolone-5-yl)sulfonamide]methyl]-N-(pyridin-3-ylmethyl)benzamide, and its chemical structure can also be represented by the following canonical SMILES: CN1C(=O)C(C)(C)C2=C1C=CC(=C2)S(=O)(=O)NCC1=CC=C(C=C1)C(=O)NCC1=CN=CC=C1; it is selected from ChemDiv library, catalog number E589-3083.

[0012] A second object of the present invention is to provide the use of the above-mentioned benzamide antibacterial compound in the preparation of antibacterial drugs.

[0013] Preferably, in this use, the antibacterial drug is an anti-staphylococcal drug or an anti-Escherichia coli drug.

[0014] Preferably, in this use, the antibacterial drug is an anti-staphylococcal drug.

[0015] Preferably, in this use, the staphylococcus is Staphylococcus aureus.

[0016] Preferably, in this use, the Escherichia coli is Escherichia coli.

[0017] A third object of the present invention is to provide an antibacterial agent comprising the above-mentioned benzamide antibacterial compounds or their pharmaceutically acceptable salts as active ingredients.

[0018] Preferably, the antibacterial agent of the present invention further includes excipients.

[0019] Preferably, the antibacterial agent of the present invention is a solid dosage form, a semi-solid dosage form, a liquid dosage form, or a gaseous dosage form.

[0020] A fourth object of the present invention is to provide a method for preparing an antibacterial agent, comprising the step of mixing the above-mentioned benzamide antibacterial compound or a pharmaceutically acceptable salt thereof with one or more excipients. The excipients may be carriers, excipients, etc.

[0021] The beneficial effects of this invention are: 1. The benzamide antibacterial compounds provided by this invention have both antibacterial and antimicrobial activities against Escherichia coli and Staphylococcus aureus.

[0022] 2. The benzamide antibacterial compounds provided by this invention have cytotoxicity of less than 10% at a concentration of <150μg / mL and have good antibacterial activity, thus having important antibacterial and antimicrobial application value. Attached Figure Description

[0023] Figure 1 These are photographs of petri dishes after treating *S. aureus* with different concentrations of benzamide-based antibacterial compounds according to the present invention. Figure 2 This is a bar chart showing the survival rate of S. aureus after treatment with different concentrations of benzamide antibacterial compounds according to the present invention. Figure 3 These are photographs of culture dishes after E. coli were treated with different concentrations of benzamide antibacterial compounds according to the present invention. Figure 4 This is a bar chart showing the survival rate of E. coli after treatment with different concentrations of benzamide antibacterial compounds according to the present invention. Figure 5 The bar chart shows the cell viability results of HL7702 hepatocytes after treatment with different concentrations of benzamide antibacterial compounds according to the present invention. Detailed Implementation

[0024] A benzamide-based antibacterial compound having the following chemical structure: .

[0025] The benzamide antibacterial compounds of the present invention exhibit good antibacterial activity against pathogens. Further research on the antibacterial activity of these benzamide antibacterial compounds is conducted as follows: a. Antibacterial activity against Staphylococcus aureus and Escherichia coli Strain selection: Staphylococcus aureus and Escherichia coli were used as experimental strains and stored at -80℃.

[0026] Bacterial suspension concentration: Staphylococcus aureus and Escherichia coli were used as experimental strains. The strains were stored at -80℃ and then thawed. After thawing, the experimental strains were inoculated into Luria Bertani (LB) broth at 37℃ and cultured. The absorbance of the bacterial suspension at 600 nm was measured using an ELISA reader to determine the concentration of the bacterial suspension.

[0027] Antibacterial activity assay: The antibacterial effects of each drug against Staphylococcus aureus and Escherichia coli were evaluated based on the plate count method.

[0028] First, the bacterial suspension was diluted with LB medium to obtain 1×10⁻⁶. 6 CFU / mL bacterial suspension was then inoculated into a culture medium, followed by the addition of the aforementioned benzamide antimicrobial compound at final concentrations of 0 μg / mL, 25 μg / mL, 50 μg / mL, 100 μg / mL, and 150 μg / mL. The mixture was incubated at 37°C for 4 h. After the above treatment, the resulting bacterial suspension was diluted 100-fold with PBS, and 100 μL was dropped onto an LB agar plate. The plate was then spread using the dilution-spreading method and incubated at 37°C for 16 h. Finally, the antimicrobial activity and bacterial survival rate of the aforementioned benzamide antimicrobial compound were evaluated by counting the colony-forming units on the culture dish.

[0029] The survival rates of Staphylococcus aureus and Escherichia coli treated with different concentrations of benzamide antibacterial compounds in this experiment are statistically shown in Table 1.

[0030] Table 1. Survival rates of Staphylococcus aureus and Escherichia coli after treatment with different concentrations of benzamide antibacterial compounds.

[0031] The following are photographs of culture dishes after treatment with different concentrations of benzamide antibacterial compounds for Staphylococcus aureus (S. aureus), as shown in the attached images. Figure 1 As shown in Table 1; the bar chart of the survival rate of Staphylococcus aureus (S. aureus) is attached. Figure 2 As shown.

[0032] The following are photographs of culture dishes of *E. coli* treated with different concentrations of benzamide compounds: Figure 3 As shown in Table 1; the bar chart of the survival rate of Escherichia coli is attached. Figure 4 As shown.

[0033] From Table 1 and Appendix Figure 1-4 It is evident that the benzamide antibacterial compounds of this invention exhibit antibacterial activity against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli).

[0034] b. Determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in vitro for Escherichia coli and Staphylococcus aureus. Test method: MIC value testing: The experimental group diluted the above-mentioned benzamide antibacterial compounds using a two-fold dilution method to obtain antibacterial solutions with concentrations of 1024 μg / mL, 512 μg / mL, 256 μg / mL, 128 μg / mL, 64 μg / mL, 32 μg / mL, 16 μg / mL, and 8 μg / mL, respectively. Then, 100 μL of each concentration of antibacterial solution and 100 μL of 1×10⁻⁶ MIC value were respectively tested. 5 CFU / mL bacterial suspension was added to 96-well plates to achieve final concentrations of benzamide antimicrobial compounds of 512 μg / mL, 256 μg / mL, 128 μg / mL, 64 μg / mL, 32 μg / mL, 16 μg / mL, 8 μg / mL, and 4 μg / mL; the control group consisted of 100 μL of LB medium and 100 μL of 10... 5 The bacterial suspension was mixed at CFU / mL; the experimental and control groups were incubated in an incubator at 37℃ and 5% carbon dioxide for 12 h; the samples were then removed for observation, and the concentration at which no sterile growth was observed was taken as the minimum inhibitory concentration (MIC). The experiment was repeated three times for both the experimental and control groups, and the average value was taken.

[0035] MBC value test: In the MIC value test, 100 μL of bacterial suspension was taken from each of the wells where no bacteria had grown and subsequent wells, and spread onto LB medium. The culture was incubated at 37℃ for 16 h, and the growth of bacteria on the medium was observed. The lowest concentration of benzamide antimicrobial compound with a bacterial colony count ≤10 is the minimum bactericidal concentration (MBC) in vitro. The above test was repeated 3 times, and the average value was taken.

[0036] The MIC value of the above-mentioned benzamide antibacterial compounds for inhibiting Escherichia coli was 64 μg / mL, and the MIC value for inhibiting Staphylococcus aureus was also 64 μg / mL; the MBC value of the above-mentioned benzamide antibacterial compounds for killing Escherichia coli was 128 μg / mL, and the MBC value for killing Staphylococcus aureus was also 64 μg / mL.

[0037] d. Cytotoxicity assay

[0038] The MTT assay was used to evaluate the cytotoxicity of the above-mentioned benzamide antibacterial compounds. The specific method is as follows: The in vitro biocompatibility of the above-mentioned benzamide antibacterial compounds was determined using normal human hepatocytes (HL7702) as a model. Logarithmic growth phase cell suspensions were seeded into 96-well plates at 8000 cells per well (100 μL per well) and cultured for 24 h. The above-mentioned benzamide antibacterial compounds were then added to the 96-well plates at final concentrations of 0 μg / mL, 25 μg / mL, 50 μg / mL, 100 μg / mL, and 150 μg / mL, and incubated for another 24 h. The cells were washed three times with PBS. 100 μL of fresh culture medium with an MTT concentration of 0.5 mg / mL was added to the 96-well plates, and after incubation for 4 h, the culture medium was removed. The purple formazan product was dissolved in DMSO for 15 min, and the absorbance was measured at 490 nm using a microplate reader to calculate cell viability.

[0039] The bar chart showing the cell viability of HL7702 cells cultured at different concentrations of benzamide antibacterial compounds is attached. Figure 5 As shown.

[0040] From the appendix Figure 5 As can be seen, compared with 0 μg / mL, the above-mentioned benzamide antibacterial compounds have a cell activity of more than 90% at a concentration of 150 μg / mL, indicating that they have low cytotoxicity.

[0041] The above test results on antibacterial activity and cytotoxicity show that the benzamide antibacterial compounds of the present invention have significant antibacterial and antimicrobial effects on Escherichia coli and Staphylococcus aureus, and have low cytotoxicity at the antibacterial and antimicrobial concentrations.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A benzamide-based antibacterial compound, characterized in that, It has a structure represented by the following formula (Ⅰ) or a pharmaceutically acceptable salt thereof: 。 2. Use of the benzamide antibacterial compound of claim 1 or a pharmaceutically acceptable salt thereof in the preparation of antibacterial drugs.

3. The use according to claim 2, characterized in that: The antibacterial drug is an anti-staphylococcal drug or an anti-Escherichia coli drug.

4. The use according to claim 2, characterized in that: The antibacterial drug is an anti-staphylococcal drug.

5. The use according to claim 3 or 4, characterized in that: Staphylococcus is Staphylococcus aureus.

6. The use according to claim 3, characterized in that: Escherichia coli is a bacterium called Escherichia coli.

7. An antibacterial agent, characterized in that, The active ingredient includes the benzamide antibacterial compound of claim 1 or a pharmaceutically acceptable salt thereof.

8. The antibacterial agent according to claim 7, characterized in that, It also includes auxiliary materials.

9. The antibacterial agent according to claim 7, characterized in that, The antibacterial agent is in solid, semi-solid, liquid, or gaseous form.

10. A method for preparing an antibacterial agent, characterized in that, The step includes mixing the benzamide antimicrobial compound of claim 1 or a pharmaceutically acceptable salt thereof with one or more excipients.

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