Abstract
Background: Tuberculosis caused by Mycobacterium tuberculosis has been reported to infect about two-third of the global population and to continuously develop multidrug resistance. DNA gyrase, a type II topoisomerase, is a promising target of the quinolone class of drugs in the treatment of tuberculosis.
Objective: The present study is focused on the design and synthesis of newer nitrogen heterocyclics containing indole, n-methyl piperazine, piperidine, and pyrrolidine ring structures.
Methods: Initially designed compounds were evaluated for their affinity to the DNA gyrase target. The molecular docking performed using FlexX indicated compounds IIb5 (1-(R)-(4-hydroxyphenyl)(4- methylpiperazin-1-yl)methyl)-3-((S)-(4-hydroxyphenyl)(4-methylpiperazin-1-yl)methyl)urea and IIc5 ((1-(R)-(4-hydroxyphenyl)(4-methylpiperazin-1-yl)methyl)-3-((S)-(4-hydroxyphenyl)(4-methylpiperazin- 1-yl)methyl) thiourea to exhibit promising binding affinity (dock score of -15.01 and -13.77) respectively when compared to the reference MFX moxifloxacin (dock score -4.40) with the target 5BS8 (DNA gyrase). Further, the best 10 compounds were synthesized by one-pot synthesis employing the reaction of indole/N-methyl piperazine/piperidine/pyrrolidine with N-substituted benzaldehydes in the presence of acetamide/urea/thiourea to afford the compounds in 54.60% to 85.47% yield. The synthesized compounds were suitably characterized using chromatographic and spectroscopic tools.
Results: In the microplate Alamar Blue assay (MABA), compounds IIb1, IIIc2, IIIb1, and IIb5 exhibited good minimum inhibitory concentrations of 1.6 μg/mL, 3.12 μg/mL, and 12.5 μg/mL, respectively, when compared to the standard rifampicin with 0.8 μg/mL inhibitory concentration. The MTB gyrase supercoiling assay performed using Mycobacterium tuberculosis gyrase supercoiling assay kit demonstrated compound IIb5 at a concentration of 300 μg/mL to show gyrase inhibition in comparison to MFX at 60 μg/mL. In the MTT assay performed using the human breast cancer cell line MCF-7, compounds IIc2, IIb5, and IIb1 showed IC50 values of 2.57 μM, 12.54 μM, and 12.75 μM, respectively, compared to doxorubicin (1.10 μM) at 7-48 hrs and 72 hrs of the study.
Conclusion: Based on these observations, N-methyl piperazine class of compounds can serve as a lead/pharmacophore for the rational design of potent molecules against MTB gyrase to combat the growing issue of MDR-TB.
[http://dx.doi.org/10.5588/ijtld.17.0835] [PMID: 29914597]
[http://dx.doi.org/10.1101/2020.04.28.20079582]
[http://dx.doi.org/10.1016/S0140-6736(10)60359-9] [PMID: 20488518]
[http://dx.doi.org/10.1093/jac/46.4.571]
[http://dx.doi.org/10.1164/ajrccm/145.5.1223] [PMID: 1586071]
[http://dx.doi.org/10.1146/annurev.biochem.70.1.369] [PMID: 11395412]
[http://dx.doi.org/10.1146/annurev.biophys.33.110502.140357] [PMID: 15139806]
[http://dx.doi.org/10.1016/S0167-4781(98)00126-2] [PMID: 9748489]
[http://dx.doi.org/10.1073/pnas.0401595101] [PMID: 15123801]
[http://dx.doi.org/10.1054/drup.1998.0068] [PMID: 11504468]
[http://dx.doi.org/10.2174/1381612013398013] [PMID: 11254893]
[http://dx.doi.org/10.2174/156802609789630947] [PMID: 19747119]
[http://dx.doi.org/10.1093/jac/dkr566] [PMID: 22279180]
[http://dx.doi.org/10.1021/bi5000564] [PMID: 24576155]
[http://dx.doi.org/10.1111/nyas.12830] [PMID: 26190223]
[http://dx.doi.org/10.1128/AAC.00695-11]
[http://dx.doi.org/10.1007/s00044-012-0101-3]
[http://dx.doi.org/10.1183/16000617.0085-2015] [PMID: 26929417]
[http://dx.doi.org/10.1056/NEJMoa1407426] [PMID: 25196020]
[http://dx.doi.org/10.1016/S0966-842X(96)10085-8]
[http://dx.doi.org/10.2174/187152607781001763] [PMID: 17970226]
[http://dx.doi.org/10.3109/10409239109114072] [PMID: 1657531]
[http://dx.doi.org/10.1007/978-3-642-79488-9_8]
[http://dx.doi.org/10.2298/JSC0510163V]
[http://dx.doi.org/10.1016/j.ejmech.2005.06.004] [PMID: 16040160]
[http://dx.doi.org/10.1016/j.bmc.2007.08.013] [PMID: 17723305]
[http://dx.doi.org/10.1016/j.bmcl.2009.10.135] [PMID: 19917527]
[http://dx.doi.org/10.15585/mmwr.mm7108a1] [PMID: 35202353]
[http://dx.doi.org/10.1164/rccm.202011-4239PP] [PMID: 33761302]
[http://dx.doi.org/10.1002/cpt.2261] [PMID: 33837535]
[http://dx.doi.org/10.1016/j.ijid.2021.03.001] [PMID: 33684562]
[http://dx.doi.org/10.1016/S1473-3099(20)30770-2] [PMID: 33587897]
[http://dx.doi.org/10.1016/j.bmcl.2009.07.010] [PMID: 19632841]
[http://dx.doi.org/10.1023/A:1023008422464]
[http://dx.doi.org/10.1002/jccs.200600086]
[http://dx.doi.org/10.1016/S0014-827X(99)00035-X] [PMID: 10384720]
[http://dx.doi.org/10.1002/bio.748] [PMID: 14981640]
[http://dx.doi.org/10.1016/j.bmc.2007.05.063] [PMID: 17561405]
[http://dx.doi.org/10.1590/S0103-50532002000600016]
[http://dx.doi.org/10.1016/j.bmc.2003.11.001] [PMID: 14738966]
[http://dx.doi.org/10.1080/00397910600602503]
[http://dx.doi.org/10.1021/ct300175w] [PMID: 26605615]
[http://dx.doi.org/10.1006/jmbi.1996.0477] [PMID: 8780787]
[http://dx.doi.org/10.1023/B:JCAM.0000017496.76572.6f] [PMID: 15072435]
[http://dx.doi.org/10.1145/1188455.1188544]
[http://dx.doi.org/10.1128/AAC.41.5.1004] [PMID: 9145860]
[http://dx.doi.org/10.1093/humrep/dem011] [PMID: 17307808]
[http://dx.doi.org/10.1016/j.diagmicrobio.2004.04.003] [PMID: 15246507]
[http://dx.doi.org/10.1128/JCM.02083-07] [PMID: 18701659]
[PMID: 16104645]
[http://dx.doi.org/10.1007/s11094-022-02597-z]
[http://dx.doi.org/10.1002/1097-0142(197403)33:3<850::AID-CNCR2820330334>3.0.CO;2-H] [PMID: 4592905]
[http://dx.doi.org/10.1016/j.ijid.2019.02.006] [PMID: 30776547]
[http://dx.doi.org/10.1093/jac/dks161] [PMID: 22635525]
[http://dx.doi.org/10.1016/j.medidd.2021.100115]
[http://dx.doi.org/10.1016/j.mimet.2019.105687] [PMID: 31415793]
[http://dx.doi.org/10.1128/AAC.03705-14] [PMID: 25348525]