Synthesis, antifungal, antibacterial activity, and computational evaluations of some novel coumarin-1,2,4-triazole hybrid compounds

Abstract

Effective plant pathogen control presents an important challenge. Pesticide resistance and associated health and environmental problems demonstrate the need for novel, safe active ingredients for plant protection. Since both coumarins and 1,2,4-triazoles show pesticidal activity, in this study, we evaluated the antimicrobial activity of coumarin-1,2,4-triazole hybrids against plant pathogenic fungi (Fusarium oxysporum, Fusarium culmorum, Macrophomina phaseolina and Sclerotinia sclerotiorum), bacterial plant pathogens (Pseudomonas syringae and Rhodococcus fascians), and beneficial bacteria (Bacillus mycoides and Bradyrhizobium japonicum). Coumarin-1,2,4-triazoles inhibited the growth of S. sclerotiorum and F. oxysporum, while no antibacterial effect on either pathogens or soil-beneficial bacteria was observed. A quantitative structure–activity relationship models for antifungal activities on S. sclerotiorum and F. oxysporum, developed using Dragon descriptors, can explain 79% and 77% of the compounds inhibitory activity, respectively. According to molecular docking, title compounds are potential sterol 14α-demethylase inhibitors, with 7-((5-mercapto-4-(p-tolyl)-4H-1,2,4-triazol-3-yl)methoxy)-4-methyl-2H-chromen-2-one as the promising candidate for further research in plant protection.

GRAPHICAL ABSTRACT

KEYWORDS:

• Coumarin-1,2,4-triazoles
• antimicrobial activity
• QSAR
• molecular docking
• sterol 14α-demethylase
• plant protection

Acknowledgements

The synthesized compounds are an output from the research project of Croatian Science Foundation, “Green Technologies in Synthesis of Heterocyclic Compounds” (UIP-2017-05-6593).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Availability of data and materials

All relevant data are within the manuscript and available from the corresponding author upon request.

Additional information

Funding

This work was supported by the Faculty of Agrobiotechnical Sciences Osijek, University of Osijek, under the project “DEFACTOPlant”, as part of the research team “Design of bioactive molecules”.