Abstract
Objectives: The slow development of major advances in drug discovery for the treatment of Mycobacterium tuberculosis (Mtb) infection suggests a compelling need for evaluation of more effective drug therapies against TB. New classes of drugs are constantly being evaluated for anti-mycobacterial activity with currently a very limited number of new drugs approved for TB treatment. Minor groove binders (MGBs) have previously revealed promising antimicrobial activity against various infectious agents; however, they have not yet been screened against Mtb.
Methods: The mycobactericidal activity of 96 MGB compounds against Mtb was determined using an H37Rv-GFP microplate assay. MGB hits were screened for their intracellular mycobactericidal efficacy against the clinical Beijing Mtb strain HN878 in bone-marrow-derived macrophages using standard cfu counting. Cell viability was assessed by CellTiter-Blue assays. Selected MGBs were encapsulated into non-ionic surfactant vesicles (NIVs) for drug delivery system evaluation.
Results: H37Rv-GFP screening yielded a hit-list of seven compounds at an MIC99 of between 0.39 and 1.56 μM. MGB-362 and MGB-364 displayed intracellular mycobactericidal activity against Mtb HN878 at an MIC50 of 4.09 and 4.19 μM, respectively, whilst being non-toxic. Subsequent encapsulation into NIVs demonstrated a 1.6- and 2.1-fold increased intracellular mycobacterial activity, similar to that of rifampicin when compared with MGB-alone formulation.
Conclusions: MGB anti-mycobacterial activities together with non-toxic properties indicate that MGB compounds constitute an important new class of drug/chemical entity, which holds promise in future anti-TB therapy. Furthermore, the ability of NIVs to better deliver entrapped MGB compounds to an intracellular Mtb infection suggests further preclinical evaluation is warranted.
Original language | English |
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Pages (from-to) | 3334-3341 |
Number of pages | 8 |
Journal | Journal of Antimicrobial Chemotherapy |
Volume | 72 |
Issue number | 12 |
Early online date | 18 Sep 2017 |
DOIs | |
Publication status | Published - 1 Dec 2017 |