Quinonoid and phenazine compounds: synthesis of new antimycobacterial prototypes

The minimum inhibitory concentrations (MICs) for the compounds were evaluated against MT H37Rv, MT rifampicin resistance (ATCC 35338) and MT isoniazid resistance (ATCC 35822). The toxicity of compounds toward a normal proliferating cell was investigated using the Alamar Blue assay. The compounds were classified by us according to their activity against MT as highly active (MIC ≤ 3 μg/mL), lowly active (3 μg/mL 100 μg/mL). Lapachol (1) and the compounds 2, 9 and 10, were considered inactive when MIC >100 μg/mL for H37Rv, ATCC 35338 and ATCC 35822 strains and the substances 3 and 4 were lowly active. With MIC value of 25, 12.5 and 25 μg/mL for MT H37Rv, MT rifampicin resistance and MT isoniazid resistance the reduced quinone 4 can be considered as an important prototype. The substance 7 was highly active [MIC ≤ 3 μg/mL (9.75 μM)] against MT H37Rv. For ATCC 35822 strains the compound was less active with MIC value of 12.5 μg/mL and for ATCC 35822 strain was inactive. The substance 7 was not cytotoxic against normal cells (IC50 > 25 μg/mL).