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

Eight 1-[(2-chlorophenyl)carbamoyl]naphthalen-2-yl alkylcarbamates and eight 1-[(2-nitrophenyl)carbamoyl]naphthalen-2-yl alkylcarbamates were tested for their activity related to the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. The PET-inhibiting activity of the compounds was relatively low; the corresponding IC50 values ranged from 0.05 to 0.664 mmol/L; and the highest activity within the series of compounds was observed for 1-[(2-chlorophenyl)-carbamoyl]naphthalen-2-yl propylcarbamate. It has been proven that the compounds are PET-inhibitors in photosystem II. Despite rather low PET-inhibiting activities, primary structure-activity trends can be discussed.

• Keywords
• PET inhibition, alkylcarbamates, hydroxynaphthalene-carboxamides, spinach chloroplasts, structure-activity relationships,
• MeSH
• Chloroplasts drug effects   metabolism   MeSH
• Photosynthesis drug effects   MeSH
• Inhibitory Concentration 50 MeSH
• Carbamates chemistry   pharmacology   MeSH
• Spinacia oleracea metabolism   MeSH
• Electron Transport drug effects   MeSH
• Structure-Activity Relationship MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Carbamates MeSH

Series of thirteen 1-[(2-chlorophenyl)carbamoyl]naphthalen-2-yl carbamates and thirteen 1-[(2-nitrophenyl)carbamoyl]naphthalen-2-yl carbamates with alkyl/cycloalkyl/arylalkyl chains were prepared and characterized. Primary in vitro screening of the synthesized compounds was performed against Staphylococcus aureus, two methicillin-resistant S. aureus strains, Mycobacterium marinum, and M. kansasii. 1-[(2-Chlorophenyl)carbamoyl]naphthalen-2-yl ethylcarbamate and 1-[(2-nitrophenyl)carbamoyl]naphthalen-2-yl ethylcarbamate showed antistaphylococcal (MICs = 42 µM against MRSA) and antimycobacterial (MICs = 21 µM) activity against the tested strains comparable with or higher than that of the standards ampicillin and isoniazid. In the case of bulkier carbamate tails (R > propyl/isopropyl), the activity was similar (MICs ca. 70 µM). Screening of the cytotoxicity of both of the most effective compounds was performed using THP-1 cells, and no significant lethal effect was observed (LD50 >30 µM). The structure-activity relationships are discussed.

• Keywords
• carbamates, hydroxynaphthalene-carboxamides, in vitro antibacterial activity, in vitro antimycobacterial activity, in vitro cytotoxicity assay, structure-activity relationships,
• MeSH
• Anti-Infective Agents * chemical synthesis   chemistry   pharmacology   MeSH
• Cytotoxins * chemical synthesis   chemistry   pharmacology   MeSH
• Carbamates * chemical synthesis   chemistry   pharmacology   MeSH
• Humans MeSH
• Methicillin-Resistant Staphylococcus aureus growth & development   MeSH
• Mycobacterium tuberculosis growth & development   MeSH
• Cell Line, Tumor MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Infective Agents * MeSH
• Cytotoxins * MeSH
• Carbamates * MeSH

A series of fifteen new N-alkoxyphenylanilides of 3-hydroxynaphthalene-2-carboxylic acid was prepared and characterized. Primary in vitro screening of the synthesized compounds was performed against Staphylococcus aureus, three methicillin-resistant S. aureus strains, Mycobacterium tuberculosis H37Ra and M. avium subsp. paratuberculosis. Some of the tested compounds showed antibacterial and antimycobacterial activity against the tested strains comparable with or higher than that of the standards ampicillin or rifampicin. 3-Hydroxy-N-(2-propoxyphenyl)naphthalene-2-carboxamide and N-[2-(but-2-yloxy)-phenyl]-3-hydroxynaphthalene-2-carboxamide had MIC = 12 µM against all methicillin-resistant S. aureus strains; thus their activity is 4-fold higher than that of ampicillin. The second mentioned compound as well as 3-hydroxy-N-[3-(prop-2-yloxy)phenyl]-naphthalene-2-carboxamide had MICs = 23 µM and 24 µM against M. tuberculosis respectively. N-[2-(But-2-yloxy)phenyl]-3-hydroxynaphthalene-2-carboxamide demonstrated higher activity against M. avium subsp. paratuberculosis than rifampicin. Screening of the cytotoxicity of the most effective antimycobacterial compounds was performed using THP-1 cells, and no significant lethal effect was observed for the most potent compounds. The compounds were additionally tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. N-(3-Ethoxyphenyl)-3-hydroxynaphthalene-2-carboxamide (IC50 = 4.5 µM) was the most active PET inhibitor. The structure-activity relationships are discussed.

• Keywords
• hydroxynaphthalene-2-carboxanilides, in vitro antibacterial activity, in vitro antimycobacterial activity, in vitro cytotoxicity, photosynthetic electron transport inhibition, structure-activity relationships,
• MeSH
• Ampicillin pharmacology   MeSH
• Anilides chemical synthesis   pharmacology   MeSH
• Anti-Bacterial Agents chemical synthesis   pharmacology   MeSH
• Cell Line MeSH
• Chloroplasts drug effects   physiology   MeSH
• Photosynthesis drug effects   physiology   MeSH
• Humans MeSH
• Methicillin-Resistant Staphylococcus aureus drug effects   growth & development   MeSH
• Microbial Sensitivity Tests MeSH
• Microbial Viability drug effects   MeSH
• Monocytes cytology   drug effects   MeSH
• Mycobacterium avium subsp. paratuberculosis drug effects   growth & development   MeSH
• Mycobacterium tuberculosis drug effects   growth & development   MeSH
• Naphthalenes chemical synthesis   pharmacology   MeSH
• Rifampin pharmacology   MeSH
• Spinacia oleracea drug effects   physiology   MeSH
• Electron Transport drug effects   physiology   MeSH
• Cell Survival drug effects   MeSH
• Structure-Activity Relationship MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Ampicillin MeSH
• Anilides MeSH
• Anti-Bacterial Agents MeSH
• Naphthalenes MeSH
• Rifampin MeSH