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System for Efficacy and Cytotoxicity Screening of Inhibitors Targeting Intracellular Mycobacterium tuberculosis
Published on: April 5, 2017
Development of Isoniazid-Pyrazole Hybrids as Potential Antitubercular Agents
Mukanda Gedeon Kadima1, Vinayak Singh2, Gobind Kumar3
1Discipline of Pharmaceutical Sciences, Westville Campus, University of KwaZulu-Natal, Durban 4000, South Africa.
International Journal of Molecular Sciences
|May 27, 2026
Summary
New isoniazid-pyrazole hybrids show potent anti-tubercular activity against drug-susceptible Mycobacterium tuberculosis strains, outperforming isoniazid. These compounds also demonstrate low toxicity and favorable drug-likeness, offering promise for future tuberculosis treatments.
Area of Science:
- Medicinal Chemistry
- Drug Discovery
- Microbiology
Background:
- Tuberculosis (TB) remains a significant global health threat, driven by drug-resistant strains of Mycobacterium tuberculosis.
- Isoniazid (INH) is a first-line anti-tubercular drug, but resistance limits its efficacy.
- Developing novel anti-TB agents with improved activity against resistant strains is crucial.
Purpose of the Study:
- To synthesize and evaluate novel isoniazid-pyrazole molecular hybrids for in vitro anti-tubercular activity.
- To assess the activity of these hybrids against drug-susceptible, multidrug-resistant (MDR), and extensively drug-resistant (XDR) Mycobacterium tuberculosis strains.
- To investigate the cytotoxicity and drug-likeness properties of the synthesized compounds.
Main Methods:
- Synthesis of INH-pyrazole hybrids (compounds 6a-o) and their precursors (4a-o).
- In vitro anti-tubercular activity testing using minimum inhibitory concentration (MIC) assays against various M. tuberculosis strains.
- Cytotoxicity evaluation using THP-1 human monocytic cells.
- In silico ADME (Absorption, Distribution, Metabolism, and Excretion) analysis for drug-likeness.
Main Results:
- Several INH-pyrazole hybrids exhibited anti-tubercular activity comparable to or exceeding isoniazid against drug-susceptible strains.
- Compounds 6a, 6d-6f, and 6m showed high potency (MIC = 0.9 µM), a 4.3-fold enhancement over INH.
- Compound 6o demonstrated improved activity against the XDR strain (MIC = 121 µM) compared to its precursor.
- All tested compounds displayed low cytotoxicity, maintaining acceptable cell viability at 10 µg/mL.
- In silico ADME analysis indicated that the hybrids comply with key drug-likeness criteria.
Conclusions:
- INH-pyrazole molecular hybrids represent a promising scaffold for developing novel anti-tubercular agents.
- These hybrids show potential for activity against drug-susceptible and, in some cases, resistant M. tuberculosis strains.
- The favorable toxicity and ADME profiles suggest their suitability for further drug development.
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