Arylthio analogs of 5,8-quinolinedione: Synthesis, characterization, antibacterial, and antifungal evaluations

Abstract

A set of bis(arylthio) substituted 5,8-quinolinedione derivatives were synthesized and investigated for their in vitro antimicrobial effect. The antibacterial and antifungal activities of 6,7-bis(arylthio)-5,8-quinolinedione (4a–f) and 6,7-bis(arylthio)-2-methyl-5,8-quinolinedione (5a–f) were evaluated against four gram-negative bacteria, three gram-positive bacteria, and three fungi strains. The bis(methoxyarylthio) 5,8-quinolinedione analogs presented better activity against especially gram-positive bacteria compared to bis(halogenarylthio) 5,8-quinolinedione analogs. Bis(3-methoxyarylthio) 5,8-quinolinedione (4e) had the same activity of the reference drug against Staphylococcus aureus. Bis(2-methoxyarylthio) 5,8-quinolinedione (4f) showed two-and-a half-fold better activity with 89.69 μM against Enterococcus faecalis, and two-fold better activity with 11.20 μM against Staphylococcus epidermidis. Bis(2-methoxyarylthio)-2-methyl-5,8-quinolinedione 5f exhibited five-fold higher antibacterial activity with 43.44 μM against E. faecalis and also eight-fold activity of the reference drug with 2.71 μM against S. epidermidis.

Graphical Abstract

Keywords:

• 67-Bis(arylthio) 58-quinolinedione
• antibacterial activity
• antifungal activity

Acknowledgments

I thank Dr. Emel Mataracı Kara for providing me the biological data of synthesized compounds from the Department of Pharmaceutical Microbiology Department in the Pharmacy Faculty at Istanbul University.

Conflicts of interest

The author declares that they have no conflicting interests.

Figure 1. Structures of 5,8-quinolinedione antibiotics.^[10–13] (a) Streptonigrin (b) Lavendamycin (c) Streptınigrone (d) Ascidiathiazone A (e) Ascidiathiazone B.

Additional information

Funding

This work was financially supported by the Scientific Research Projects Coordination Unit of Istanbul University-Cerrahpasa (Project number: FBA-2016-20662) for supplying the equipment and materials.