Synthesis, In Vitro and In Silico Studies of Indolequinone Derivatives against Clinically Relevant Bacterial Pathogens

Title:Synthesis, In Vitro and In Silico Studies of Indolequinone Derivatives against Clinically Relevant Bacterial Pathogens

Volume: 20 Issue: 3

Author(s): Talita Odriane Custodio Leite, Juliana Silva Novais, Beatriz Lima Cosenza de Carvalho, Vitor Francisco Ferreira, Leonardo Alves Miceli, Letícia Fraga, Bárbara Abrahim-Vieira, Carlos Rangel Rodrigues, Agnes Marie Sá Figueiredo, Helena Carla Castro*Anna Claudia Cunha*

Affiliation:

• Universidade Federal Fluminense, Programas de Pos-Graduacao em Patologia (HUAP) e em Ciencias e Biotecnologia (PPBI), 24020-150, Niteroi, Rio de Janeiro,Brazil

• Universidade Federal Fluminense, Instituto de Quimica, Departamento de Quimica Organica, Programa de Pos- Graduacao em Quimica, 24020-141, Niteroi, Rio de Janeiro,Brazil

Keywords: Indolequinone, Antimicrobial, β-enamino ketones, Staphylococcus aureus, MRSA, Molecular docking.

Abstract:

Background: According to the World Health Organization, antimicrobial resistance is one of the most important public health threats of the 21st century. Therefore, there is an urgent need for the development of antimicrobial agents with new mechanism of action, especially those capable of evading known resistance mechanisms.

Objective: We described the synthesis, in vitro antimicrobial evaluation, and in silico analysis of a series of 1H-indole-4,7-dione derivatives.

Methods: The new series of 1H-indole-4,7-diones was prepared with good yield by using a copper(II)- mediated reaction between bromoquinone and β-enamino ketones bearing alkyl or phenyl groups attached to the nitrogen atom. The antimicrobial potential of indole derivatives was assessed. Molecular docking studies were also performed using AutoDock 4.2 for Windows. Characterization of all compounds was confirmed by one- and two-dimensional NMR techniques 1H and 13C NMR spectra [1H, 13C – APT, 1H x 1H – COSY, HSQC and HMBC], IR and mass spectrometry analysis.

Results: Several indolequinone compounds showed effective antimicrobial profile against Grampositive (MIC = 16 µg.mL-1) and Gram-negative bacteria (MIC = 8 µg.mL-1) similar to antimicrobials current on the market. The 3-acetyl-1-(2,5-dimethylphenyl)-1H-indole-4,7-dione derivative exhibited an important effect against different biofilm stages formed by a serious hospital life-threatening resistant strain of Methicillin-Resistant Staphylococcus aureus (MRSA). A hemocompatibility profile analysis based on in vitro hemolysis assays revealed the low toxicity effects of this new series. Indeed, in silico studies showed a good pharmacokinetics and toxicological profiles for all indolequinone derivatives, reinforcing their feasibility to display a promising oral bioavailability. An elucidation of the promising indolequinone derivatives binding mode was achieved, showing interactions with important sites to biological activity of S. aureus DNA gyrase. These results highlighted 3-acetyl-1-(2-hydroxyethyl)-1Hindole- 4,7-dione derivative as broad-spectrum antimicrobial prototype to be further explored for treating bacterial infections.

Conclusion: The highly substituted indolequinones were obtained in moderate to good yields. The pharmacological study indicated that these compounds should be exploited in the search for a leading substance in a project aimed at obtaining new antimicrobials effective against Gram-negative bacteria.

Cite this article as:

Leite Odriane Custodio Talita , Novais Silva Juliana , de Carvalho Lima Cosenza Beatriz , Ferreira Francisco Vitor , Miceli Alves Leonardo , Fraga Letícia , Abrahim-Vieira Bárbara , Rodrigues Rangel Carlos , Sá Figueiredo Marie Agnes , Castro Carla Helena *, Cunha Claudia Anna *, Synthesis, In Vitro and In Silico Studies of Indolequinone Derivatives against Clinically Relevant Bacterial Pathogens, Current Topics in Medicinal Chemistry 2020; 20 (3) . https://dx.doi.org/10.2174/1568026620666191223110518