Antimicrobial amino esters

Abstract

A method of treating a subject contaminated or suspected of being contaminated by one or more microorganisms, the method comprising contacting the subject with a compound such that the compound kills or inhibits growth of at least a portion of the one or more microorganisms, wherein the compound has the formula 1: # imgabs0 # or a pharmaceutically acceptable salt thereof, wherein: R1 is a C4-C20 alkyl group or a C4-C20 alkenyl group; and R2 is hydrogen, C1-C4 alkyl or a side chain of a naturally occurring amino acid.

Description

Technical Field

[0001] The present disclosure generally relates to the use of amino esters as antimicrobial agents. Background Art

[0002] Microbial infections can cause a variety of diseases and even death, and have always been an important issue in global public health. Therefore, the development of antimicrobial materials or agents is of great significance for reducing the morbidity and mortality caused by microbial infections. To date, several types of antimicrobial materials have been reported. The first type is metal-based antimicrobial materials, including metal ions, oxides, and chalcogenides such as silver, copper, and zinc. However, the use of heavy metals may cause safety problems. Another area of development is antimicrobial peptides (AMPs), which are usually peptide oligomers containing dozens of amino acids. AMPs generally exhibit very high antimicrobial activity. However, due to their protein-like structure, their stability against pH and thermal changes is insufficient. Cationic polymers with guanidine and quaternary ammonium end groups have shown promising applications in antimicrobial surface treatment, but their biocompatibility is generally poor. It has been reported that some natural products, usually essential oils (EOs) and chitin, also exhibit antimicrobial properties. Summary of the Invention

[0003] A series of broad-spectrum antimicrobial amino esters are provided herein, which have a very clear chemical structure and structure-activity relationship. The amino esters can be prepared from lactic acid, amino acids, and fatty alcohols by a simple esterification reaction and purified by recrystallization. In addition to excellent antimicrobial properties, the amino esters are biodegradable, biocompatible, cost-effective, and easy to produce in batches. The relationship between the chemical structure and antimicrobial potency has also been studied, which can provide a general strategy for the design of green antimicrobial materials.

[0004] In a first aspect, a method of treating an object contaminated or suspected of being contaminated with one or more microorganisms is provided herein, the method comprising contacting the object with a compound such that the compound kills at least a portion of one or more microorganisms or inhibits the growth of at least a portion of one or more microorganisms, wherein the compound has Formula 1:

[0005]

[0006] or a pharmaceutically acceptable salt or zwitterion thereof, wherein:

[0007] R 1 is C 4 -C 20 alkyl or C 4 -C20 an alkenyl group; and

[0008] R 2 is hydrogen, C 1 -C 4 alkyl, or the side chain of a naturally occurring amino acid.

[0009] In certain embodiments, R 1 is C 10 -C 20 alkyl or C 10 -C 20 alkenyl.

[0010] In certain embodiments, R 1 is C 10 -C 18 alkyl or C 10 -C 18 alkenyl.

[0011] In certain embodiments, R 2 is selected from the group consisting of:

[0012] and pharmaceutically acceptable salts or zwitterions thereof, wherein R and N together with the carbon to which they are attached form a 5-membered heterocycloalkyl group.

[0013] In certain embodiments, R 2 is hydrogen or C 1 -C 2 alkyl.

[0014] In certain embodiments, R 1 is C 10 -C 18 alkyl or C 10 -C 18 alkenyl; and R 2 is hydrogen or C 1 -C 2 alkyl.

[0015] In certain embodiments, R 1 is C 10 -C 18 alkyl and R 2 is C 1 -C 2 alkyl.

[0016] In certain embodiments, R 1 is C 12 alkyl and R 2 is methyl.

[0017] In certain embodiments, one or more microorganisms include bacteria, fungi, viruses, or mixtures thereof.

[0018] In certain embodiments, one or more microorganisms include Gram-positive bacteria or Gram-negative bacteria.

[0019] In certain embodiments, one or more microorganisms are selected from the group consisting of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Candida albicans (C. albicans), and methicillin-resistant Staphylococcus aureus.

[0020] In certain embodiments, the method includes contacting an object with a disinfectant composition comprising a compound and a solvent.

[0021] In certain embodiments, the solvent comprises water.

[0022] In certain embodiments, the compound is present in the solvent in the form of nanoparticles.

[0023] In certain embodiments, the nanoparticles have an average diameter of 50 nm to 200 nm.

[0024] In certain embodiments, the compound is present in the disinfectant composition at a concentration of at least 80 μg / mL.

[0025] In certain embodiments, the compound is present in the disinfectant composition at a concentration of 90 μg / mL to 500 μg / mL.

[0026] In certain embodiments, the disinfectant composition further comprises quaternary ammonium chloride, triclosan, or triclocarban. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above aspects of the present invention and many attendant advantages will become more readily appreciated by reference to the following detailed description taken in conjunction with the accompanying drawings.

[0028] Figure 1 Depicts the 1 1H NMR spectrum of Ala4 in CDCl3.

[0029] Figure 2 Depicts the high-resolution mass spectrum of Ala4.

[0030] Figure 3 Depicts CD 3 OD of Ala12 1 1H NMR spectrum.

[0031] Figure 4 Depicts the high-resolution mass spectrum of Ala12.

[0032] Figure 5 Depicts the dynamic light scattering (DLS) spectrum of Ala12.

[0033] Figure 6 Depicts the results of antimicrobial testing of Ala12 against Escherichia coli, Staphylococcus aureus, Candida albicans, and methicillin-resistant S. aureus (MRSA) according to certain embodiments described herein.

[0034] Figure 7 Depicts a table presenting the minimum inhibitory concentration (MIC) of different esters against Escherichia coli and Staphylococcus aureus. Detailed Description

[0035] Definition

[0036] Throughout this disclosure, unless the context requires otherwise, the word "comprise", "comprises", "comprising" or variations thereof will be understood to mean including the stated integer or group of integers, but not excluding any other integer or group of integers. Also note that in this disclosure, particularly in the claims and / or paragraphs, terms such as "comprise", "comprised", "comprising" etc. may have the meaning given to them in United States patent law; for example, they may mean "includes", "included", "including" etc.; and terms such as "consisting essentially of" have the meaning given to them in United States patent law, for example, they allow the presence of elements not expressly recited, but exclude elements found in the prior art or elements that affect the basic or novel characteristics of the invention.

[0037] Furthermore, throughout this disclosure and the claims, unless the context requires otherwise, the word "include" or variations thereof such as "include" or "include" will be understood to mean including the stated integer or group of integers, but not excluding any other integer or group of integers.

[0038] Unless otherwise expressly stated, a noun used without an article in this document includes one or more of the stated object (and vice versa). Further, when the term "about" is used before a numerical value, unless otherwise specifically stated, the present teachings also include the specific numerical value itself. As used herein, the term "about" means a variation of ±10%, ±7%, ±5%, ±3%, ±1% or ±0% of the nominal value, unless otherwise stated or inferred.

[0039] As used herein, the term "Gram-positive bacteria" refers to bacteria characterized by having peptidoglycan, as well as polysaccharides and / or teichoic acids as part of their cell wall structure, and by reacting blue-violet in the Gram staining procedure.

[0040] As used herein, the term "Gram-negative bacteria" refers to bacteria characterized by the presence of a double membrane around each bacterial cell and by being colorless after washing with a decolorizing agent and pink when counterstained with safranin in the Gram staining procedure.

[0041] The term "composition" is intended to encompass a product containing specified amounts of specified ingredients, as well as any product directly or indirectly resulting from the combination of specified amounts of the specified ingredients.

[0042] As used herein, unless otherwise indicated, the phrase "pharmaceutically acceptable salts" includes salts of acidic or basic groups that may be present in the compounds described herein. Compounds described herein that contain basic groups, such as amines, are capable of forming a wide variety of salts with a multitude of inorganic and organic acids. Acids useful for preparing pharmaceutically acceptable acid addition salts of such basic compounds described herein are those that form relatively non-toxic acid addition salts, i.e., salts containing pharmacologically acceptable anions, such as acetate, besylate, benzoate, bicarbonate, bisulfate, bitartrate, borate, bromide, calcium edetate, camphorsulfonate, carbonate, chloride, clavulanate, citrate, dihydrochloride, edetate, edislyate, estolate, esylate, ethyl succinate, fumarate, glucoheptonate, gluconate, glutamate, glycollylarsanilate, hexylresorcinate, hydrabamine, hydrobromide, hydrochloride, iodide, isothionate, lactate, lactobionate, laurate, malate, maleate, mandelate, mesylate, methylsulfate, mucate, napsylate, nitrate, oleate, oxalate, pamoate (embonate), palmitate, pantothenate, phosphate / diphosphate, polygalacturonate, salicylate, stearate, subacetate, succinate, tannate, tartrate, teoclate, tosylate, triethiodide, and valerate.

[0043] In other instances, the compounds described herein may contain one or more acidic functional groups and thus be capable of forming pharmaceutically acceptable salts with pharmaceutically acceptable bases. In these instances, the term "pharmaceutically acceptable salts" refers to relatively non-toxic inorganic and organic base addition salts of the compounds of the invention. These salts can likewise be prepared in situ during the formation of the medicament vehicle or dosage form, or by separately reacting the purified compound in its free acid form with a suitable base, such as the hydroxide, carbonate, or bicarbonate of a pharmaceutically acceptable metal cation, with ammonia, or with a pharmaceutically acceptable organic primary, secondary, or tertiary amine. Representative alkali metal or alkaline earth metal salts include lithium, sodium, potassium, calcium, magnesium, and aluminum salts, among others. Representative organic amines useful for the formation of base addition salts include ethylamine, diethylamine, ethylenediamine, ethanolamine, diethanolamine, piperazine, and the like.

[0044] The present invention provides a method for treating an object contaminated or suspected of being contaminated with one or more microorganisms, the method comprising contacting the object with a compound such that the compound kills at least a portion of one or more microorganisms or inhibits their growth, wherein the compound has the formula 1:

[0045]

[0046] or a pharmaceutically acceptable salt or zwitterion thereof, wherein:

[0047] R 1 is C 4 -C 20 alkyl or C 4 -C 20 alkenyl; and

[0048] R 2 is hydrogen, C 1 -C 4 alkyl or the side chain of a naturally occurring amino acid.

[0049] R 1 can be a straight-chain alkyl, straight-chain alkenyl, branched-chain alkyl, branched-chain alkenyl, cycloalkyl or cycloalkenyl. In certain embodiments, R 1 is C 5 -C 20 alkyl, C 6 -C 20 alkyl, C 7 -C 20 alkyl, C 8 -C 20 alkyl, C 9 -C 20 alkyl, C 10 -C 20 alkyl, C 11 -C 20 alkyl, C 12 -C 20 alkyl, C 12 -C 19 alkyl, C 12 -C 18 alkyl, C 12 -C 17 alkyl, C 12 -C 16 alkyl, C 12 -C 15 alkyl, C 12 -C 14 alkyl, C 12 -C 13 alkyl, C 8 -C 16 alkyl, C 9 -C15 Alkyl, C 10 -C 14 Alkyl, C 11 -C 13 Alkyl, R 1 is C 5 -C 20 Alkenyl, C 6 -C 20 Alkenyl, C 7 -C 20 Alkenyl, C 8 -C 20 Alkenyl, C 9 -C 20 Alkenyl, C 10 -C 20 Alkenyl, C 11 -C 20 Alkenyl, C 12 -C 20 Alkenyl, C 12 -C 19 Alkenyl, C 12 -C 18 Alkenyl, C 12 -C 17 Alkenyl, C 12 -C 16 Alkenyl, C 12 -C 15 Alkenyl, C 12 -C 14 Alkenyl, C 12 -C 13 Alkenyl, C 8 -C 16 Alkenyl, C 9 -C 15 Alkenyl, C 10 -C 14 Alkenyl or C 11 -C 13 Alkenyl. In which R 1 is C 4 -C 20 Alkenyl, for example, R 1 can contain 1, 2, 3 or more alkenes. Exemplary R 1 groups include but are not limited to n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl and n-hexadecyl. In certain embodiments, R 1 is n-dodecyl.

[0050] R 2 can be a straight-chain alkyl, branched-chain alkyl, cycloalkyl or hydrogen. In certain embodiments, R 2 is hydrogen, C 1 -C 4 Alkyl, C1 -C 3 alkyl or C 1 -C 2 alkyl. Exemplary R 2 groups include hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. In certain embodiments, R 2 is methyl.

[0051] In instances where R 2 is the side chain of a naturally occurring amino acid, R 2 can be selected from the group consisting of:

[0052] and its pharmaceutically acceptable salts or zwitterions, wherein R and N together with the carbon to which they are attached form a 5-membered heteroalkyl (i.e., proline).

[0053] In certain embodiments, the compound of formula 1 has the following formula:

[0054]

[0055] or its pharmaceutically acceptable salts.

[0056] Dynamic light scattering (DLS) and zeta potential indicate that Ala12 assembles into nanoparticles with an average size of about 50 nm to 200 nm ( Figure 5 ), and the surface potential of the generated nanoparticles can be +2.15 mV, which means the nanoparticles are positively charged and the hydrophilic -NH 2 groups may be distributed on the outer surface. The self-assembly of the positively charged nanoparticles will attack the negatively charged membrane of microorganisms through electrostatic attraction, which is more effective than the Brownian motion of neutral nanoparticles and is thus the main reason for the high antimicrobial efficacy.

[0057] The bacteria can be Gram-positive bacteria, Gram-negative bacteria, Gram-variable bacteria, or Gram-indeterminate bacteria.

[0058] Exemplary Gram-negative bacteria include, but are not limited to, Acinetobacter calcoaceticus, Acinetobacter baumannii, Actinobacillus actinomycetemcomitans, Aeromonas hydrophila, Alcaligenes xylosoxidans, Bacteroides spp., Bacteroides fragilis, Bartonella bacilliformis, Bordetella spp., Borrelia burgdorferi, Branhamella catarrhalis, Brucella spp., Campylobacter spp., Chlamydia pneumoniae, Chlamydia psittaci, Chlamydia trachomatis, Chromobacterium violaceum, Citrobacter spp., Eikenella corrodens, Enterobacter aerogenes, E. coli, Flavobacterium meningosepticum, Fusobacterium spp., Haemophilus influenzae, Haemophilus spp., Helicobacter pylori, Klebsiella pneumoniae, Klebsiella spp., Legionella spp., Leptospira spp.) Moraxella catarrhalis, Morganella morganii, Mycoplasma pneumoniae, Neisseria gonorrhoeae, Neisseria meningitidis, Pasteurella multocida, Plesiomonas shigelloides, Prevotella spp., Proteus spp., Providencia rettgeri, Pseudomonas aeruginosa, Pseudomonas spp., Rickettsia prowazekii, Rickettsia rickettsii, Rochalimaea spp., Salmonella spp., Salmonella typhimurium, Serratia marcescens, Shigella spp., Shigella sonnei, Treponema carateum, Treponema pallidum, Treponema pallidum endemicum, Treponema pertenue, Veillonella spp., Vibrio cholerae, Vibrio vulnificus, Yersinia enterocolitica, Yersinia pestis.

[0059] Exemplary Gram-positive bacteria include, but are not limited to, species of the genus Actinomyces (Actinomyces spp.), Bacillus anthracis, species of the genus Bifidobacterium (Bifidobacterium spp.), Clostridium botulinum, Clostridium perfringens, species of the genus Clostridium (Clostridium spp.), Clostridium tetani, Corynebacterium diphtheriae, Corynebacterium jeikeium, Enterococcus faecalis, Enterococcus faecium, Erysipelothrix rhusiopathiae, species of the genus Eubacterium (Eubacterium spp.), Gardnerella vaginalis, Gemella morbillorum, species of the genus Leuconostoc (Leuconostoc spp.), Mycobacterium abscessus, Mycobacterium avium complex, Mycobacterium chelonae, Mycobacterium fortuitum, Mycobacterium haemophilium, Mycobacterium kansasii, Mycobacterium leprae, Mycobacterium marinum, Mycobacterium scrofulaceum, Mycobacterium smegmatis, Mycobacterium terrae, Mycobacterium tuberculosis, Mycobacterium ulcerans, species of the genus Nocardia (Nocardia spp.), Peptococcus niger, species of the genus Peptostreptococcus (Peptostreptococcus spp.) Species of the genus Propionibacterium, Sarcina lutea, Staphylococcus aureus, Staphylococcus auricularis, Staphylococcus capitis, Staphylococcus cohnii, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus lugdanensis, Staphylococcus saccharolyticus, Staphylococcus saprophyticus, Staphylococcus schleiferi, Staphylococcus similans, Staphylococcus warneri, Staphylococcus xylosus, Streptococcus agalactiae (Group B streptococcus), Streptococcus anginosus, Streptococcus bovis, Streptococcus canis, Streptococcus equi, Streptococcus milleri, Streptococcus mitior, Streptococcus mutans, Streptococcus pneumoniae, Streptococcus pyogenes (Group A streptococcus), and Streptococcus salivarius, Streptococcus sanguis.

[0060] The MIC of the compounds described herein against Escherichia coli (E. coil, ATCC No.: 25922) and Staphylococcus aureus (S. aureus, ATCC No.: 6538) was measured by the broth microdilution method as Figure 7 shown. It can be clearly seen that the terminal group and the length of the alkyl chain significantly affect the antimicrobial performance, and compared with the neutral -OH group, the positively charged -NH 2 group will significantly reduce the MIC.

[0061] The antimicrobial performance and MIC of Ala12 against fungi (Candida albicans) and methicillin-resistant Staphylococcus aureus (MRSA) were 390 μg / mL, respectively. The rapid bactericidal test of Ala12 showed that the amino ester killed the microorganisms within 10 minutes (standard: ASTM E2149 13a 1015). Ala12 exhibited excellent biosafety and had no skin irritation and skin sensitization at concentrations up to 3.9 mg / mL (according to the ISO 10993-10:2010 standard). The antibacterial test results of Ala12 against Escherichia coli, Staphylococcus aureus, Candida albicans and MRSA are as Figure 6 shown.

[0062] The subject can be an animal or a non-animal subject. Animals (such as mammals) can include humans, non-human primates, canines, felines, and rodents.

[0063] Non-animal subjects can include, but are not limited to, surfaces (such as residential and hospital surfaces), curtains, textiles, electrical appliances, food processing equipment, military equipment, personal protective equipment, medical devices, household items, and building structures.

[0064] The compounds described herein can be prepared using any number of synthetic schemes. The selection of a suitable synthetic method is entirely within the capabilities of those of ordinary skill in the art. In certain embodiments, the compounds described herein are prepared by the condensation of amino acids, as shown in the following reaction scheme:

[0065]

[0066] where R 1 and R 2 are as defined herein.

[0067] In a typical procedure, amino acids, fatty alcohols, and trimethylchlorosilane (TMSCl) react in a molar ratio of 1:4:5 by refluxing for 4 hours until the reaction is complete, and then cooled to room temperature. The amino ester product is recrystallized as a white precipitate from a cold ether / ethanol solution, and its chemical structure is fully characterized by 1 1H NMR and HPLC-MS spectra and is in excellent agreement with the predicted spectra (see, for example Figure 3 and Figure 4 ).

[0068] Example

[0069] Synthesis of Example 1 - Ala4

[0070] For the typical synthesis of Ala4, first, 1.00 g of alanine (11.2 mmol) and 3.50 g of n-butanol (44.8 mmol) were added to a single-necked flask, and then trimethylchlorosilane (6.05 g, 56.0 mmol) was slowly added to the mixture. Then the mixture was refluxed for 4 hours. Excess butanol and by-products were removed by rotary evaporation. Ala4 was recrystallized as a white powder from cold ether / ethanol.

[0071] Synthesis of Example 2 - Ala12

[0072] For the typical synthesis of Ala12, first, 1.00 g of alanine (11.2 mmol) and 8.43 g of lauryl alcohol (44.8 mmol) were added to a single-necked flask, and then trimethylchlorosilane (6.05 g, 56.0 mmol) was slowly added to the mixture. Then the mixture was refluxed for 4 hours. Excess lauryl alcohol and by-products were removed by rotary evaporation. Ala12 was recrystallized as a white powder from cold ether / ethanol.

[0073] Example 3 - Antimicrobial Test

[0074] Ala12 was diluted to 10 mg / mL with phosphate buffer. Its antibacterial activity was detected using the oscillating method (see ASTM standard E2149 13a2015), where the PBS group was used as a blank control. The contact time for treating bacteria with Ala12 was 10 minutes.

Claims

1. A method for treating an object contaminated or suspected of being contaminated by one or more microorganisms, the method comprising contacting the object with a compound such that the compound kills at least a portion of the one or more microorganisms or inhibits the growth of at least a portion of the one or more microorganisms, wherein the compound has Formula 1: or a pharmaceutically acceptable salt or zwitterion thereof, wherein: R 1 It is C4-C 20 Alkyl or C4-C 20 alkenyl; and R 2 is hydrogen, C1-C4 alkyl, or the side chain of a naturally occurring amino acid.

2. The method according to claim 1, wherein R 1 It is C 10 -C 20 Alkyl or C 10 -C 20 Alkenyl.

3. The method according to claim 1, wherein R 1 It is C 10 -C 18 Alkyl or C 10 -C 18 Alkenyl.

4. The method according to claim 1, wherein R 2 Selected from the group consisting of: and pharmaceutically acceptable salts or zwitterions thereof, wherein R and N together with the carbon to which they are attached form a 5-membered heterocycloalkyl.

5. The method according to claim 1, wherein R 2 It is hydrogen or C1-C2 alkyl.

6. The method according to claim 1, wherein R 1 It is C 10 -C 18 Alkyl or C 10 -C 18 alkenyl; and R 2 It is hydrogen or C1-C2 alkyl.

7. The method according to claim 1, wherein R 1 It is C 10 -C 18 Alkyl and R 2 It is a C1-C2 alkyl group.

8. The method according to claim 1, wherein R 1 It is C 12 Alkyl and R 2 It's methyl.

9. The method of claim 1, wherein the one or more microorganisms comprise bacteria, fungi, viruses, or mixtures thereof.

10. The method of claim 1, wherein the one or more microorganisms comprise Gram-positive bacteria or Gram-negative bacteria.

11. The method of claim 8, wherein the one or more microorganisms are selected from the group consisting of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Candida albicans (C. albicans), and methicillin-resistant Staphylococcus aureus.

12. The method of claim 1, wherein the method comprises contacting the object with a disinfectant composition comprising the compound and a solvent.

13. The method of claim 12, wherein the solvent comprises water.

14. The method of claim 12, wherein the compound is present in the solvent in the form of nanoparticles.

15. The method of claim 14, wherein the nanoparticles have an average diameter of 50 nm to 200 nm.

16. The method of claim 12, wherein the compound is present in the disinfectant composition at a concentration of at least 80 μg / mL.

17. The method of claim 12, wherein the compound is present in the disinfectant composition at a concentration of 90 μg / mL to 500 μg / mL.

18. The method of claim 12, wherein the disinfectant composition further comprises quaternary ammonium chloride, triclosan, or triclocarban.

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