BACKGROUND AND PURPOSE: New compounds and innovative therapeutic approaches are trying to prevent antimicrobial resistance, which has become a global health challenge. EXPERIMENTAL APPROACH: This study includes a series of twelve mono-, di- and trichlorinated 1-hydroxynaphthalene-2-carboxanilides designed as multitarget agents. All compounds were evaluated for their antistaphylococcal activity. Furthermore, MTT assay and chemoproteomic analysis of selected compounds were performed. Cytotoxicity in human cells was also tested. KEY RESULTS: N-(3,5-Dichlorophenyl)-1-hydroxynaphthalene-2-carboxamide (10) demonstrated activity comparable to or higher than clinically used drugs, with minimum inhibitory concentrations (MICs) of 0.37 μM. The compound was equally effective against clinical isolates of methicillin-resistant S. aureus. On the other hand, compound 10 showed 96 % inhibition of S. aureus respiration only at a concentration of 16× MIC. Chemoproteomic analysis revealed that the effect of agent 10 on staphylococci resulted in the downregulation of four proteins. This compound expressed no in vitro cytotoxicity up to a concentration of 30 μM. CONCLUSION: From the set of tested mono-, di- and trisubstituted derivatives, it is evident that the position of chlorine atoms is decisive for significant antistaphylococcal activity. Inhibition of energy metabolism does not appear to be one of the main mechanisms of action of compound 10; on the contrary, the antibacterial effect may likely be contributed by downregulation of proteins (especially ATP-dependent protease ATPase subunit HslU) involved in processes essential for bacterial survival and growth, such as protein, nucleotide/nucleic acid synthesis and efficient protein repair/degradation.

• Keywords
• Lipophilicity, MTT assay, antistaphylococcal activity, chemoproteomic analysis, cytotoxicity,
• Publication type
• Journal Article MeSH

BACKGROUND AND PURPOSE: Many new compounds are being prepared to overcome the problem of increasing microbial resistance and the increasing number of infections. EXPERIMENTAL APPROACH: This study includes a series of twenty-seven mono-, di- and trisubstituted 2-hydroxynaphthalene-1-carboxanilides designed as multitarget agents. The compounds are substituted with methoxy, methyl, and nitro groups, as well as additionally with chlorine, bromine, and trifluoromethyl at various positions. All the compounds were evaluated for antibacterial activities against Gram-positive and Gram-negative bacteria and mycobacteria. Cytotoxicity on human cells was also tested. KEY RESULTS: Three compounds showed activity comparable to clinically used drugs. N-(3,5-Dimethylphenyl)-2-hydroxynaphthalene-1-carboxamide (13) showed only antistaphylococcal activity (minimum inhibitory concentration (MIC) = 54.9 μM); 2-hydroxy-N-[2-methyl-5-(trifluoromethyl)phenyl]naphthalene-1-carboxamide (22) and 2-hydroxy-N-[4-nitro-3-(trifluoromethyl)phenyl]naphthalene-1-carboxamide (27) were active across the entire spectrum of tested bacteria/mycobacteria, both against the sensitive set and against resistant isolates (MICs range 0.3 to 92.6 μM). Compound 22 was even active against E. coli (MIC = 23.2 μM). The active agents showed no in vitro cytotoxicity up to a concentration of 30 μM. CONCLUSION: Compounds with trifluoromethyl in the meta-anilide position, experimental lipophilicity expressed as log k (logarithm of the capacity factor) in the range of 0.31 to 0.34 and calculated electron σ parameter for the anilide substituent higher than 0.59 were effective. The investigated compounds meet the definition of Michael acceptors. Based on ADME screening, the investigated compounds 13, 22 and 27 should have suitable physicochemical parameters for good bioavailability in the organism. Therefore, these are promising agents for further study.

• Keywords
• Lipophilicity, antibacterial activity, antimycobacterial activity, cytotoxicity,
• Publication type
• Journal Article MeSH

A series of nine 2,3-disubstituted-quinazolin-4(3H)-one derived Schiff bases and their three Cu(II) complexes was prepared and tested for their antimicrobial activities against reference strains Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212 and resistant clinical isolates of methicillin-resistant S. aureus (MRSA) and vancomycin-resistant E. faecalis (VRE). All the substances were tested in vitro against Mycobacterium tuberculosis H37Ra ATCC 25177, M. kansasii DSM 44162 and M. smegmatis ATCC 700084. While anti-enterococcal and antimycobacterial activities were insignificant, 3-[(E)-(2-hydroxy-5-nitrobenzylidene)amino]-2-(2-hydroxy-5-nitrophenyl)-2,3-dihydroquinazolin-4(1H)-one (SB3) and its Cu(II) complex (SB3-Cu) demonstrated bacteriostatic antistaphylococcal activity. In addition, both compounds, as well as the other two prepared complexes, showed antibiofilm activity, which resulted in a reduction of biofilm formation and eradication of mature S. aureus biofilm by 80% even at concentrations lower than the values of their minimum inhibitory concentrations. In addition, the compounds were tested for their cytotoxic effect on the human monocytic leukemia cell line THP-1. The antileukemic efficiency was improved by the preparation of Cu(II) complexes from the corresponding non-chelated Schiff base ligands.

• Keywords
• Antibacterial activity, Antibiofilm effect, Cu(II) complexes, Cytotoxicity, Quinazolinones, Schiff bases,
• Publication type
• Journal Article MeSH

A series of eleven benzylated intermediates and eleven target compounds derived from salicylanilide were tested against Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212 as reference strains and against three clinical isolates of methicillin-resistant S. aureus (MRSA) and three isolates of vancomycin-resistant E. faecalis. In addition, the compounds were evaluated against Mycobacterium tuberculosis H37Ra and M. smegmatis ATCC 700084. The in vitro cytotoxicity of the compounds was assessed using the human monocytic leukemia cell line THP-1. The lipophilicity of the prepared compounds was experimentally determined and correlated with biological activity. The benzylated intermediates were found to be completely biologically inactive. Of the final eleven compounds, according to the number of amide groups in the molecule, eight are diamides, and three are triamides that were inactive. 5-Chloro-2-hydroxy-N-[(2S)- 4-(methylsulfanyl)-1-oxo-1-{[4-(trifluoromethyl)phenyl]amino}butan-2-yl]benzamide (3e) and 5-chloro-2-hydroxy-N-[(2S)-(4-methyl-1-oxo-1-{[4-(trifluoromethyl)phenyl]amino)pentan-2-yl)benzamide (3f) showed the broadest spectrum of activity against all tested species/isolates comparable to the used standards (ampicillin and isoniazid). Six diamides showed high antistaphylococcal activity with MICs ranging from 0.070 to 8.95 μM. Three diamides showed anti-enterococcal activity with MICs ranging from 4.66 to 35.8 μM, and the activities of 3f and 3e against M. tuberculosis and M. smegmatis were MICs of 18.7 and 35.8 μM, respectively. All the active compounds were microbicidal. It was observed that the connecting linker between the chlorsalicylic and 4-CF3-anilide cores must be substituted with a bulky and/or lipophilic chain such as isopropyl, isobutyl, or thiabutyl chain. Anticancer activity on THP-1 cells IC50 ranged from 1.4 to >10 µM and increased with increasing lipophilicity.

• Keywords
• antimicrobial activity, cytotoxicity, lipophilicity, peptidomimetics, salicylamide, structure–activity relationships,
• MeSH
• Ampicillin MeSH
• Anilides MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Benzamides MeSH
• Isoniazid MeSH
• Humans MeSH
• Methicillin-Resistant Staphylococcus aureus * MeSH
• Microbial Sensitivity Tests MeSH
• Mycobacterium tuberculosis * MeSH
• Peptidomimetics * MeSH
• Salicylanilides pharmacology   MeSH
• Vancomycin MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Ampicillin MeSH
• Anilides MeSH
• Anti-Bacterial Agents MeSH
• Benzamides MeSH
• Isoniazid MeSH
• Peptidomimetics * MeSH
• salicylanilide MeSH Browser
• Salicylanilides MeSH
• Vancomycin MeSH

A set of twenty-four 3-hydroxynaphthalene-2-carboxanilides, disubstituted on the anilide ring by combinations of methoxy/methyl/fluoro/chloro/bromo and ditrifluoromethyl groups at different positions, was prepared. The compounds were tested for their ability to inhibit photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. N-(3,5-Difluorophenyl)-, N-(3,5-dimethylphenyl)-, N-(2,5-difluorophenyl)- and N-(2,5-dimethylphenyl)-3-hydroxynaphthalene-2-carboxamides showed the highest PET-inhibiting activity (IC50 ~ 10 µM) within the series. These compounds were able to inhibit PET in photosystem II. It has been found that PET-inhibiting activity strongly depends on the position of the individual substituents on the anilide ring and on the lipophilicity of the compounds. The electron-withdrawing properties of the substituents contribute towards the PET activity of these compounds.

• Keywords
• PET inhibition, hydroxynaphthalene-carboxamides, spinach chloroplasts, structure-activity relationships,
• MeSH
• Chloroplasts drug effects   metabolism   MeSH
• Photosynthesis drug effects   MeSH
• Photosystem II Protein Complex antagonists & inhibitors   metabolism   MeSH
• Herbicides chemistry   metabolism   MeSH
• Naphthalenes chemistry   metabolism   MeSH
• Spinacia oleracea drug effects   metabolism   MeSH
• Electron Transport drug effects   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Photosystem II Protein Complex MeSH
• Herbicides MeSH
• Naphthalenes MeSH

A series of twenty-two novel N-(disubstituted-phenyl)-3-hydroxynaphthalene- 2-carboxamide derivatives was synthesized and characterized as potential antimicrobial agents. N-[3,5-bis(trifluoromethyl)phenyl]- and N-[2-chloro-5-(trifluoromethyl)phenyl]-3-hydroxy- naphthalene-2-carboxamide showed submicromolar (MICs 0.16-0.68 µM) activity against methicillin-resistant Staphylococcus aureus isolates. N-[3,5-bis(trifluoromethyl)phenyl]- and N-[4-bromo-3-(trifluoromethyl)phenyl]-3-hydroxynaphthalene-2-carboxamide revealed activity against M. tuberculosis (both MICs 10 µM) comparable with that of rifampicin. Synergistic activity was observed for the combinations of ciprofloxacin with N-[4-bromo-3-(trifluoromethyl)phenyl]- and N-(4-bromo-3-fluorophenyl)-3-hydroxynaphthalene-2-carboxamides against MRSA SA 630 isolate. The similarity-related property space assessment for the congeneric series of structurally related carboxamide derivatives was performed using the principal component analysis. Interestingly, different distribution of mono-halogenated carboxamide derivatives with the -CF3 substituent is accompanied by the increased activity profile. A symmetric matrix of Tanimoto coefficients indicated the structural dissimilarities of dichloro- and dimetoxy-substituted isomers from the remaining ones. Moreover, the quantitative sampling of similarity-related activity landscape provided a subtle picture of favorable and disallowed structural modifications that are valid for determining activity cliffs. Finally, the advanced method of neural network quantitative SAR was engaged to illustrate the key 3D steric/electronic/lipophilic features of the ligand-site composition by the systematic probing of the functional group.

• Keywords
• CoMSA, IVE-PLS, MIC, MTT assay, antistaphylococcal activity, antitubercular activity, hydroxynaphthalenecarboxamides, lipophilicity, similarity-activity landscape index,
• MeSH
• Anti-Infective Agents chemical synthesis   MeSH
• Methicillin-Resistant Staphylococcus aureus * MeSH
• Microbial Sensitivity Tests MeSH
• Mycobacterium tuberculosis * MeSH
• Naphthalenes chemistry   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Infective Agents MeSH
• Naphthalenes MeSH
• naphthalene-2-carboxamide MeSH Browser

A series of sixteen ring-substituted N-arylcinnamanilides, previously described as highly antimicrobially effective against a wide spectrum of bacteria and fungi, together with two new derivatives from this group were prepared and characterized. Moreover, the molecular structure of (2E)-N-(2-bromo-5-fluorophenyl)-3-phenylprop-2-enamide as a model compound was determined using single-crystal X-ray analysis. All the compounds were tested for their anti-inflammatory potential, and most tested compounds significantly attenuated the lipopolysaccharide-induced NF-κB activation and were more potent than the parental cinnamic acid. (2E)-N-[2-Chloro-5-(trifluoromethyl)phenyl]-3-phenylprop-2-enamide, (2E)-N-(2,6-dibromophenyl)- 3-phenylprop-2-enamide, and (2E)-N-(2,5-dichlorophenyl)-3-phenylprop-2-enamide demonstrated the highest inhibition effect on transcription factor NF-κB at the concentration of 2 µM and showed a similar effectiveness as the reference drug prednisone. Several compounds also decreased the level of TNF-α. Nevertheless, subsequent tests showed that the investigated compounds affect neither IκBα level nor MAPKs activity, which suggests that the N-arylcinnamanilides may have a different mode of action to prednisone. The modification of the C(2,5)' or C(2,6)' positions of the anilide core by rather lipophilic and bulky moieties seems to be preferable for the anti-inflammatory potential of these compounds.

• Keywords
• X-ray structure, anti-inflammatory potential, cinnamamides, polypharmacology,
• MeSH
• Anti-Inflammatory Agents chemical synthesis   chemistry   pharmacology   MeSH
• Cinnamates chemical synthesis   chemistry   pharmacology   MeSH
• Crystallography, X-Ray MeSH
• Humans MeSH
• Lipopolysaccharides adverse effects   MeSH
• Models, Molecular MeSH
• Molecular Structure MeSH
• NF-kappa B metabolism   MeSH
• Gene Expression Regulation drug effects   MeSH
• Signal Transduction drug effects   MeSH
• THP-1 Cells MeSH
• Tumor Necrosis Factor-alpha metabolism   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Inflammatory Agents MeSH
• Cinnamates MeSH
• Lipopolysaccharides MeSH
• NF-kappa B MeSH
• TNF protein, human MeSH Browser
• Tumor Necrosis Factor-alpha MeSH

A set of 25 novel, silicon-based carbamate derivatives as potential acetyl- and butyrylcholinesterase (AChE/BChE) inhibitors was synthesized and characterized by their in vitro inhibition profiles and the selectivity indexes (SIs). The prepared compounds were also tested for their inhibition potential on photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. In fact, some of the newly prepared molecules revealed comparable or even better inhibitory activities compared to the marketed drugs (rivastigmine or galanthamine) and commercially applied pesticide Diuron®, respectively. Generally, most compounds exhibited better inhibition potency towards AChE; however, a wider activity span was observed for BChE. Notably, benzyl N-[(1S)-2-[(tert-butyldimethylsilyl)oxy]-1-[(2-hydroxyphenyl)carbamoyl]ethyl]-carbamate (2) and benzyl N-[(1S)-2-[(tert-butyldimethylsilyl)oxy]-1-[(3-hydroxyphenyl)carbamoyl]ethyl]-carbamate (3) were characterized by fairly high selective indexes. Specifically, compound 2 was prescribed with the lowest IC50 value that corresponds quite well with galanthamine inhibition activity, while the inhibitory profiles of molecules 3 and benzyl-N-[(1S)-2-[(tert-butyldimethylsilyl)oxy]-1-[(4-hydroxyphenyl)carbamoyl]ethyl]carbamate (4) are in line with rivastigmine activity. Moreover, a structure-activity relationship (SAR)-driven similarity evaluation of the physicochemical properties for the carbamates examined appeared to have foreseen the activity cliffs using a similarity-activity landscape index for BChE inhibitory response values. The 'indirect' ligand-based and 'direct' protein-mediated in silico approaches were applied to specify electronic/steric/lipophilic factors that are potentially valid for quantitative (Q)SAR modeling of the carbamate analogues. The stochastic model validation was used to generate an 'average' 3D-QSAR pharmacophore pattern. Finally, the target-oriented molecular docking was employed to (re)arrange the spatial distribution of the ligand property space for BChE and photosystem II (PSII).

• Keywords
• CoMSA, IVE-PLS, in vitro cholinesterase inhibition, molecular docking, silicon-based carbamates, similarity-activity landscape index,
• MeSH
• Butyrylcholinesterase MeSH
• Chloroplasts MeSH
• Cholinesterase Inhibitors chemistry   pharmacology   MeSH
• Photosystem II Protein Complex MeSH
• Inhibitory Concentration 50 MeSH
• Carbamates chemistry   pharmacology   MeSH
• Silicon chemistry   MeSH
• Humans MeSH
• Ligands MeSH
• Molecular Docking Simulation MeSH
• Spinacia oleracea MeSH
• THP-1 Cells drug effects   MeSH
• Electron Transport drug effects   MeSH
• Binding Sites MeSH
• Cell Survival drug effects   MeSH
• Structure-Activity Relationship MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Butyrylcholinesterase MeSH
• Cholinesterase Inhibitors MeSH
• Photosystem II Protein Complex MeSH
• Carbamates MeSH
• Silicon MeSH
• Ligands MeSH

A series of twenty-six methoxylated and methylated N-aryl-1-hydroxynaphthalene- 2-carboxanilides was prepared and characterized as potential anti-invasive agents. The molecular structure of N-(2,5-dimethylphenyl)-1-hydroxynaphthalene-2-carboxamide as a model compound was determined by single-crystal X-ray diffraction. All the analysed compounds were tested against the reference strain Staphylococcus aureus and three clinical isolates of methicillin-resistant S. aureus as well as against Mycobacterium tuberculosis and M. kansasii. In addition, the inhibitory profile of photosynthetic electron transport in spinach (Spinacia oleracea L.) chloroplasts was specified. In vitro cytotoxicity of the most effective compounds was tested on the human monocytic leukaemia THP-1 cell line. The activities of N-(3,5-dimethylphenyl)-, N-(3-fluoro-5-methoxy-phenyl)- and N-(3,5-dimethoxyphenyl)-1-hydroxynaphthalene-2-carbox- amide were comparable with or even better than the commonly used standards ampicillin and isoniazid. All promising compounds did not show any cytotoxic effect at the concentration >30 µM. Moreover, an in silico evaluation of clogP features was performed for the entire set of the carboxamides using a range of software lipophilicity predictors, and cross-comparison with the experimentally determined lipophilicity (log k), in consensus lipophilicity estimation, was conducted as well. Principal component analysis was employed to illustrate noticeable variations with respect to the molecular lipophilicity (theoretical/experimental) and rule-of-five violations. Additionally, ligand-oriented studies for the assessment of the three-dimensional quantitative structure-activity relationship profile were carried out with the comparative molecular surface analysis to determine electron and/or steric factors that potentially contribute to the biological activities of the investigated compounds.

• Keywords
• 3D-QSAR, CoMSA, MTT assay, PET inhibition, X-Ray structure, antimycobacterial activity, antistaphylococcal activity, cytotoxicity, hydroxynaphthalenecarboxamides, lipophilicity,
• MeSH
• Ampicillin pharmacology   MeSH
• Principal Component Analysis MeSH
• Anilides chemical synthesis   chemistry   pharmacology   MeSH
• Anti-Bacterial Agents chemical synthesis   chemistry   pharmacology   MeSH
• Chloroplasts drug effects   physiology   MeSH
• Photosynthesis drug effects   MeSH
• Isoniazid pharmacology   MeSH
• Humans MeSH
• Methicillin-Resistant Staphylococcus aureus drug effects   growth & development   MeSH
• Methylation MeSH
• Microbial Sensitivity Tests MeSH
• Mycobacterium kansasii drug effects   growth & development   MeSH
• Mycobacterium tuberculosis drug effects   growth & development   MeSH
• Naphthols chemical synthesis   chemistry   pharmacology   MeSH
• Spinacia oleracea chemistry   drug effects   metabolism   MeSH
• THP-1 Cells MeSH
• Electron Transport drug effects   MeSH
• Structure-Activity Relationship MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Comparative Study MeSH
• Names of Substances
• Ampicillin MeSH
• Anilides MeSH
• Anti-Bacterial Agents MeSH
• Isoniazid MeSH
• Naphthols MeSH

A series of 116 small-molecule 1-hydroxynaphthalene-2-carboxanilides was designed based on the fragment-based approach and was synthesized according to the microwave-assisted protocol. The biological activity of all of the compounds was tested on human colon carcinoma cell lines including a deleted TP53 tumor suppressor gene. The mechanism of activity was studied according to the p53 status in the cell. Several compounds revealed a good to excellent activity that was similar to or better than the standard anticancer drugs. Some of these appeared to be more active against the p53 null cells than their wild-type counterparts. Intercalating the properties of these compounds could be responsible for their mechanism of action.

• MeSH
• Apoptosis drug effects   MeSH
• DNA metabolism   MeSH
• Doxorubicin pharmacology   MeSH
• HCT116 Cells MeSH
• Intercalating Agents pharmacology   MeSH
• Small Molecule Libraries chemistry   pharmacology   MeSH
• Humans MeSH
• Models, Molecular MeSH
• Tumor Suppressor Protein p53 metabolism   MeSH
• Naphthols chemical synthesis   chemistry   pharmacology   MeSH
• Cell Proliferation drug effects   MeSH
• Antineoplastic Agents chemical synthesis   chemistry   pharmacology   MeSH
• Drug Design * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• 1-naphthol MeSH Browser
• calf thymus DNA MeSH Browser
• DNA MeSH
• Doxorubicin MeSH
• Intercalating Agents MeSH
• Small Molecule Libraries MeSH
• Tumor Suppressor Protein p53 MeSH
• Naphthols MeSH
• Antineoplastic Agents MeSH