Application of carbazole derivative in prevention and treatment of dairy cow mastitis pathogenic bacteria

Abstract

The invention discloses application of carbazole derivatives C1-1 to C1-12, C2-1 to C2-5, C3-1 to C3-10, C4-1 to C4-3 and C5-1 to C5-2 to prevention and treatment of pathogenic bacteria of cow mastitis, and belongs to the field of natural medicinal chemistry. The compound disclosed by the invention has good inhibitory activity on the pathogenic bacteria, such as Streptococcus agalactiae ATCC27956, Streptococcus dysgalactiae ATCC27957 and Staphylococcus aureus, of the mastitis of the dairy cow, and the compound disclosed by the invention has good inhibitory activity on the pathogenic bacteria, such as Streptococcus agalactiae ATCC27956, Streptococcus dysgalactiae ATCC27957 and Staphylococcus aureus. The carbazole derivative has the characteristics of simple structure, easiness in synthesis, low price, wide application and the like, and has further research and development values in the aspect of preventing and treating the cow mastitis.

Description

Technical Field

[0001] The invention belongs to the field of natural drug chemistry and discloses a new use of a carbazole derivative, in particular to the use of the carbazole derivative in preventing and treating cow mastitis caused by Streptococcus agalactiae ATCC27956, Streptococcus dysgalactiae ATCC27957, Escherichia coli ATCC 25922 and Staphylococcus aureus Newman. Background Art

[0002] Milk and its derivatives are rich in nutrients and are a common food for people of all ages. Although milk and dairy products are widely consumed, mastitis in dairy cows (usually caused by bacteria) has caused people to worry about the quality of milk. The main cause of mastitis in dairy cows is the invasion of pathogenic microorganisms into the mammary glands of dairy cows, among which Streptococcus agalactiae and Streptococcus dysgalactiae are the main bacterial pathogens causing mastitis in dairy cows. The current treatment of mastitis mainly relies on antibiotics, which is also the main reason for the use of antibiotics in dairy cows. However, the emergence of drug-resistant strains is threatening the feasibility of antibiotic treatment of mastitis.

[0003] Carbazole is composed of a central pyrrole ring and two benzene rings, and has a unique structure of a tricyclic aromatic basic skeleton. In addition, there have been many reports that natural compounds and synthetic derivatives containing carbazole structures have a variety of biological activities, such as antibacterial, antiviral, and antitumor activities, so natural carbazole alkaloids and carbazole derivatives have received extensive attention.

[0004] The invention uses carbazole derivatives to carry out activity screening on main pathogenic bacteria of cow mastitis, including Streptococcus agalactiae ATCC27956, Streptococcus dysgalactiae ATCC27957, Escherichia coli ATCC 25922 and Staphylococcus aureus Newman, and the results show good antibacterial activity, indicating that these carbazole derivatives have broad application prospects for preventing and treating cow mastitis and are worth further research and development. Summary of the invention

[0005] The purpose of the present invention is to provide a new use of carbazole derivatives in treating cow mastitis, which is used for preventing and treating cow mastitis caused by Streptococcus agalactiae, Streptococcus dysgalactiae, Escherichia coli and Staphylococcus aureus.

[0006] In order to achieve the above objectives, the present invention provides the following technical methods:

[0007] The invention provides a new use of a carbazole derivative in resisting pathogenic bacteria of cow mastitis. The dosage concentrations of the carbazole derivative for Streptococcus agalactiae ATCC27956, Streptococcus dysgalactiae ATCC27957, Escherichia coli ATCC 25922 and Staphylococcus aureus Newman are 100, 50, 25, 12.5, 6.25, 3.12 μg / mL and the like.

[0008] The invention adopts the method reported in the literature to synthesize carbazole derivatives, and separates the pure products through conventional methods such as multiple silica gel column chromatography. The structures of carbazole derivatives C1-1~C1-12, C2-1~C2-5, C3-1~C3-10, C4-1~C4-3, and C5-1~C5-2 are determined by spectral techniques such as mass spectrometry and nuclear magnetic resonance.

[0009] Among them, compounds C1-1 to C1-12 and C2-1 to C2-5 are as shown in Chemical Formula 1, and R1 can be thiazol-2-ylmethyl, furan-2-ylmethyl, thien-2-ylmethyl, 6-chloropyridin-3-ylmethyl, pyridin-2-ylmethyl, pyridin-4-ylmethyl, pyrimidin-2-ylmethyl, (1H-benzo[d]imidazol-2-yl)methyl, (1H-indol-2-yl)methyl, (1H-indol-3-yl)methyl, 2-(1H-indol-2-yl)ethyl, 2-morpholinylethyl, benzyl, 4-fluorobenzyl, 4-chlorobenzyl, 4-trifluoromethylbenzyl, 4-methoxybenzyl; compounds C3-1 to C3-10 are as shown in chemical formula 2, R2 can be hydrogen, 4-methoxyphenyl, 4-fluorophenyl, 4-chlorophenyl, 2,4-difluorophenyl, 3,4-dichlorophenyl, benzyl, 4-fluorobenzyl, 3,5-difluorobenzyl, 3,4-dichlorobenzyl; compounds C4-1 to C4-3 are as shown in chemical formula 3, R3 can be benzyl, pyridin-2-ylmethyl, cyclopentyl; compounds C5-1 to C5-2 are as shown in chemical formula 4, R4 can be hydrogen or allyl.

[0010]

[0011] Specifically, the chemical structural formula of the carbazole derivative is:

[0012]

[0013]

[0014]

[0015]

[0016] The antibacterial agent provided by the present invention has the following advantages:

[0017] 1) The present invention finds that the carbazole compound involved exhibits excellent inhibitory effect on the pathogenic bacteria of bovine mastitis and has great application value in treating bovine mastitis.

[0018] 2) The carbazole derivatives involved have the characteristics of easy synthesis, simple structure, and cheap raw materials. They have application value in preventing and treating bovine mastitis and are worthy of further research and development. DETAILED DESCRIPTION

[0019] In order to better understand the present invention, the above contents of the present invention are further described in detail through the following specific examples. However, this should not be understood as limiting the present invention. The following are specific embodiments of the present invention, which further describe the technical scheme of the present invention, but the contents of the present invention are not limited to the scope described in the embodiments, and any changes or equivalent substitutions that do not deviate from the concept of the present invention are included in the protection scope of the present invention.

[0020] Example 1: Determination of the activity of carbazole derivatives against pathogenic bacteria causing bovine mastitis

[0021] 1) Test reagent: carbazole derivative.

[0022] 2) Test bacteria: Streptococcus agalactiae ATCC27956, Streptococcus dysgalactiae ATCC27957, Escherichia coli ATCC 25922 and Staphylococcus aureus Newman.

[0023] 3) Test method:

[0024] The strains used in this experiment were frozen in the laboratory at -80℃ with 30% glycerol. The frozen strains of Streptococcus agalactiae and Streptococcus dysgalactiae were taken out and streaked on TSA (tryptic soy peptone agar medium) + 5% sheep blood agar plates, and cultured at 37℃ until single colonies grew. Single colonies were picked and added to brain heart infusion broth (BHI) liquid culture medium (tryptone: 10.0g, beef heart extract powder: 17.5g, sodium chloride: 5.0g, glucose: 2.0g, disodium hydrogen phosphate (12H2O): 2.5g, distilled water: 1L; sterilized at 121℃ for 20min), and cultured at 37℃, 140rpm constant temperature shaker until the logarithmic growth phase. Similarly, the frozen strains of Escherichia coli and Staphylococcus aureus were taken out and streaked on MH solid culture medium (beef powder: 2.0g, soluble starch: 1.5g, acid hydrolyzed casein: 17.5g, agar: 20g, distilled water: 1L; sterilized at 121℃ for 20min), and cultured at 37℃ until single colonies grew. Single colonies were picked and added to MH broth medium (beef powder: 2.0g, soluble starch: 1.5g, acid hydrolyzed casein: 17.5g, distilled water: 1L; sterilized at 121℃ for 20min). Then, the strains in the logarithmic growth phase were diluted to about 10 with the corresponding liquid culture medium. 6 Dissolve the compounds in DMSO, add them to the liquid culture medium, mix them evenly, and prepare the compounds into a drug-containing liquid culture medium with a concentration of 200 μg / mL. Take 50 μL of the drug-containing culture medium and the same volume of the drug-containing medium containing about 10 6 CFU / mL bacterial culture was added to the wells of a 96-well plate, and the final compound administration concentration was 100 μg / mL. 100 μL of bacterial solution of the same concentration containing an equal amount of DMSO was used as a control. The 96-well plate was cultured in a 37°C constant temperature incubator for 12 hours until the control group bacterial solution grew, and the OD value (OD 600 ). In addition, the OD values ​​of 100 μL of liquid culture medium and the drug with a concentration of 100 μg / mL were measured to correct the OD values ​​caused by the culture medium and the drug itself. The calculation formula for the corrected OD value and inhibition rate is as follows:

[0025] Corrected OD value = OD value of bacterial culture medium - OD value of sterile culture;

[0026] Inhibition rate = (corrected control culture medium bacterial solution OD value - corrected drug-containing culture medium OD value) / corrected control culture medium bacterial solution OD value × 100%

[0027] All experiments were repeated three times, and the inhibition rates of the compounds were shown in Table 1.

[0028] Table 1. Inhibition rate of carbazole derivatives at 100 μg / mL on pathogenic bacteria of bovine mastitis (%)

[0029]

[0030]

[0031] From the results in Table 1, it can be seen that most of the carbazole derivatives of the present invention exhibit certain antibacterial activity against the tested strains at 100 μg / mL, and some exhibit high antibacterial activity.

[0032] The drug-containing liquid culture medium of the active compound was diluted by a two-fold dilution method in a 96-well plate to obtain 50 μL of drug-containing culture medium of a series of concentrations, and then the inhibition rate corresponding to the series of concentrations was determined according to the same test method as in Example 1. The lowest concentration with an inhibition rate greater than 90% was defined as MIC, and the activity data obtained by the determination are shown in Table 2.

[0033] Table 2. MIC values ​​of terpenoids against pathogenic bacteria of bovine mastitis

[0034]

[0035]

[0036] From the results in Table 1 and Table 2, it can be seen that the carbazole derivatives involved in the present invention show good antibacterial activity against the test strains except Escherichia coli. The inhibition rate of most compounds at 100 μg / mL is greater than 90%. Compounds C1-10 and C4-2 have the best activity, with MIC values ​​ranging from 1.56 to 6.25 μg / mL, showing excellent antibacterial activity.

[0037] In summary, the carbazole derivatives of the present invention show good antibacterial activity against Streptococcus agalactiae ATCC27956, Streptococcus dysgalactiae ATCC27957, and Staphylococcus aureus Newman, have research prospects in the prevention and treatment of bovine mastitis, and are worthy of further research and development.

Claims

1. Use of a carbazole derivative in preventing and treating pathogenic bacteria of dairy cow mastitis.

2. The use according to claim 1, wherein The structural formula of the compound involved is as follows:

3. Use of the carbazole derivatives according to claims 1 and 2 in preventing and treating cow mastitis caused by Streptococcus agalactiae ATCC27956, Streptococcus dysgalactiae ATCC27957, Escherichia coli ATCC 25922, and Staphylococcus aureus Newman.

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