Anti-tubercular activity and molecular docking studies of indolizine derivatives targeting mycobacterial InhA enzyme

• Main Authors: Katharigatta N. Venugopala, Sandeep Chandrashekharappa, Pran Kishore Deb, Christophe Tratrat, Melendhran Pillay, Deepak Chopra, Nizar A. Al-Shar’i, Wafa Hourani, Lina A. Dahabiyeh, Pobitra Borah, Rahul D. Nagdeve, Susanta K. Nayak, Basavaraj Padmashali, Mohamed A. Morsy, Bandar E. Aldhubiab, Mahesh Attimarad, Anroop B. Nair, Nagaraja Sreeharsha, Michelyne Haroun, Sheena Shashikanth, Viresh Mohanlall, Raghuprasad Mailavaram
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2021-01-01
• Series: Journal of Enzyme Inhibition and Medicinal Chemistry
• Subjects: indolizine; mycobacterium tuberculosis; inha; docking; x-ray crystal structure
• Online Access: http://dx.doi.org/10.1080/14756366.2021.1919889
• ISSN: 1475-6366; 1475-6374

A series of 1,2,3-trisubstituted indolizines (2a–2f, 3a–3d, and 4a–4c) were screened for in vitro whole-cell anti-tubercular activity against the susceptible H37Rv and multidrug-resistant (MDR) Mycobacterium tuberculosis (MTB) strains. Compounds 2b–2d, 3a–3d, and 4a–4c were active against the H37Rv-MTB strain with minimum inhibitory concentration (MIC) ranging from 4 to 32 µg/mL, whereas the indolizines 4a–4c, with ethyl ester group at the 4-position of the benzoyl ring also exhibited anti-MDR-MTB activity (MIC = 16–64 µg/mL). In silico docking study revealed the enoyl-acyl carrier protein reductase (InhA) and anthranilate phosphoribosyltransferase as potential molecular targets for the indolizines. The X-ray diffraction analysis of the compound 4b was also carried out. Further, a safety study (in silico and in vitro) demonstrated no toxicity for these compounds. Thus, the indolizines warrant further development and may represent a novel promising class of InhA inhibitors and multi-targeting agents to combat drug-sensitive and drug-resistant MTB strains.