Development and evaluation of novel InhA inhibitors inspired by thiadiazole and tetrahydropyran series of inhibitors

Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a leading global health challenge, exacerbated by the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. One promising therapeutic target is the enzyme enoyl-acyl carrier protein reductase (InhA), whic...

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Main Authors: Rambaher Martina Hrast, Gradišek Nina, Frlan Rok, Sosič Izidor, Bolje Aljoša, Kljun Jakob, Juhás Martin, Gobec Stanislav, Pajk Stane
Format: Article
Language:English
Published: Sciendo 2025-06-01
Series:Acta Pharmaceutica
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Online Access:https://doi.org/10.2478/acph-2025-0016
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author Rambaher Martina Hrast
Gradišek Nina
Frlan Rok
Sosič Izidor
Bolje Aljoša
Kljun Jakob
Juhás Martin
Gobec Stanislav
Pajk Stane
author_facet Rambaher Martina Hrast
Gradišek Nina
Frlan Rok
Sosič Izidor
Bolje Aljoša
Kljun Jakob
Juhás Martin
Gobec Stanislav
Pajk Stane
author_sort Rambaher Martina Hrast
collection DOAJ
description Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a leading global health challenge, exacerbated by the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. One promising therapeutic target is the enzyme enoyl-acyl carrier protein reductase (InhA), which plays a vital role in the biosynthesis of mycolic acids, essential components of the bacterial cell wall. Direct inhibition of InhA offers a potential strategy for overcoming resistance mechanisms, particularly in cases where the activation of conventional drugs like isoniazid is compromised. This study investigates two novel series of InhA inhibitors based on thiadiazole and tetrahydropyran lead compounds, originally identified through high-throughput screening by GSK. Analogues were synthesised using the copper-catalysed azide-alkyne cycloaddition (CuAAC) click reaction, and their inhibitory activity was tested against InhA. Among the tested compounds, only one exhibited modest inhibitory activity, with an IC50 of 11 µmol L–1, while others were inactive. Interestingly, during the synthetic efforts, a novel reaction was discovered between aryl methyl ketones and ethynylmagnesium bromide, yielding 1,3-diols, as confirmed by X-ray diffraction analysis. These findings underscore the challenges of optimising InhA inhibitors and highlight the potential of synthetic innovations in exploring new synthetic pathways.
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spelling doaj-art-8c0ca840976345e8a00b537a35ffa4382025-08-20T02:37:13ZengSciendoActa Pharmaceutica1846-95582025-06-0175218521810.2478/acph-2025-0016Development and evaluation of novel InhA inhibitors inspired by thiadiazole and tetrahydropyran series of inhibitorsRambaher Martina Hrast0Gradišek Nina1Frlan Rok2Sosič Izidor3Bolje Aljoša4Kljun Jakob5Juhás Martin6Gobec Stanislav7Pajk Stane81University of Ljubljana, Faculty of Pharmacy, 1000Ljubljana, Slovenia1University of Ljubljana, Faculty of Pharmacy, 1000Ljubljana, Slovenia1University of Ljubljana, Faculty of Pharmacy, 1000Ljubljana, Slovenia1University of Ljubljana, Faculty of Pharmacy, 1000Ljubljana, Slovenia1University of Ljubljana, Faculty of Pharmacy, 1000Ljubljana, Slovenia2University of Ljubljana, Faculty of Chemistry and Chemical Technology, 1000Ljubljana, Slovenia1University of Ljubljana, Faculty of Pharmacy, 1000Ljubljana, Slovenia1University of Ljubljana, Faculty of Pharmacy, 1000Ljubljana, Slovenia1University of Ljubljana, Faculty of Pharmacy, 1000Ljubljana, SloveniaTuberculosis (TB), caused by Mycobacterium tuberculosis, remains a leading global health challenge, exacerbated by the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. One promising therapeutic target is the enzyme enoyl-acyl carrier protein reductase (InhA), which plays a vital role in the biosynthesis of mycolic acids, essential components of the bacterial cell wall. Direct inhibition of InhA offers a potential strategy for overcoming resistance mechanisms, particularly in cases where the activation of conventional drugs like isoniazid is compromised. This study investigates two novel series of InhA inhibitors based on thiadiazole and tetrahydropyran lead compounds, originally identified through high-throughput screening by GSK. Analogues were synthesised using the copper-catalysed azide-alkyne cycloaddition (CuAAC) click reaction, and their inhibitory activity was tested against InhA. Among the tested compounds, only one exhibited modest inhibitory activity, with an IC50 of 11 µmol L–1, while others were inactive. Interestingly, during the synthetic efforts, a novel reaction was discovered between aryl methyl ketones and ethynylmagnesium bromide, yielding 1,3-diols, as confirmed by X-ray diffraction analysis. These findings underscore the challenges of optimising InhA inhibitors and highlight the potential of synthetic innovations in exploring new synthetic pathways.https://doi.org/10.2478/acph-2025-0016tuberculosisinhadirect inhibitorsclick reaction1,3-diol synthesis
spellingShingle Rambaher Martina Hrast
Gradišek Nina
Frlan Rok
Sosič Izidor
Bolje Aljoša
Kljun Jakob
Juhás Martin
Gobec Stanislav
Pajk Stane
Development and evaluation of novel InhA inhibitors inspired by thiadiazole and tetrahydropyran series of inhibitors
Acta Pharmaceutica
tuberculosis
inha
direct inhibitors
click reaction
1,3-diol synthesis
title Development and evaluation of novel InhA inhibitors inspired by thiadiazole and tetrahydropyran series of inhibitors
title_full Development and evaluation of novel InhA inhibitors inspired by thiadiazole and tetrahydropyran series of inhibitors
title_fullStr Development and evaluation of novel InhA inhibitors inspired by thiadiazole and tetrahydropyran series of inhibitors
title_full_unstemmed Development and evaluation of novel InhA inhibitors inspired by thiadiazole and tetrahydropyran series of inhibitors
title_short Development and evaluation of novel InhA inhibitors inspired by thiadiazole and tetrahydropyran series of inhibitors
title_sort development and evaluation of novel inha inhibitors inspired by thiadiazole and tetrahydropyran series of inhibitors
topic tuberculosis
inha
direct inhibitors
click reaction
1,3-diol synthesis
url https://doi.org/10.2478/acph-2025-0016
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