Thymoquinone and 3HQ synergy inhibits CTX-M-15 ESBL

Karem Ibrahem; Mohammad  Alrabia; Asif Fatani; Sameer E.M. Alharthi; Hani Zakareya  Asfour; Nabil A. Alhakamy; Hatoon A.  Niyazi; Hisham N. Altayb; Ahmad M.  Sait; Philip J.R.  Day; Abdalbagi Alfadil

doi:10.17305/bb.2025.12431

Authors

Karem Ibrahem Department of Clinical Microbiology and Immunology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
Mohammad Alrabia Department of Clinical Microbiology and Immunology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia; Center of Research Excellence for Drug Research and Pharmaceutical Industries, King Abdulaziz University, Jeddah, Saudi Arabia.
Asif Fatani Department of Clinical Microbiology and Immunology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia; Department of Clinical Microbiology Laboratory, King Abdulaziz University Hospital, Jeddah, Saudi Arabia.
Sameer E.M. Alharthi Department of Pharmacology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
Hani Zakareya Asfour Department of Clinical Microbiology and Immunology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
Nabil A. Alhakamy Center of Research Excellence for Drug Research and Pharmaceutical Industries, King Abdulaziz University, Jeddah, Saudi Arabia; Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia; Mohamed Saeed Tamer Chair for Pharmaceutical Industries, King Abdulaziz University, Jeddah, Saudi Arabia.
Hatoon A. Niyazi Department of Clinical Microbiology and Immunology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
Hisham N. Altayb Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
Ahmad M. Sait Medical Laboratory Science, Faculty of Applied Medical Science, King Abdulaziz University, Jeddah, Saudi Arabia; Regenerative Medicine Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.
Philip J.R. Day Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK; Department of Medicine, University of Cape Town, Cape Town, South Africa.
Abdalbagi Alfadil Department of Clinical Microbiology and Immunology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia; Center of Research Excellence for Drug Research and Pharmaceutical Industries, King Abdulaziz University, Jeddah, Saudi Arabia.

DOI:

https://doi.org/10.17305/bb.2025.12431

Keywords:

AMR, ESBL , FICI, 3HQ, thymoquinone

Abstract

Bacterial infections remain a significant cause of mortality worldwide, further aggravated by the escalating issue of antibiotic resistance. Extended-Spectrum Beta-Lactamases (ESBLs) pose a substantial challenge, capable of hydrolyzing various beta-lactam antibiotics. The slow pace of drug discovery, coupled with the rapid emergence of drug-resistant bacteria, underscores the urgent need for innovative therapeutic solutions. Thymoquinone (TQ), derived from the seeds of Nigella sativa, has demonstrated notable antibacterial activity against Gram-negative bacteria, including Escherichia coli and Pseudomonas aeruginosa. Previous research has established the efficacy of quinoxaline derivatives, such as 3-hydrazinoquinoxaline-2-thiol (3HQ), against Methicillin-Resistant Staphylococcus aureus (MRSA). This study investigates the potential synergy between 3HQ and TQ against various clinical strains of ESBL. The minimum inhibitory concentrations (MICs) of TQ and 3HQ were evaluated against 18 clinical ESBL strains, revealing MIC values ranging from 16 to 128 µg/mL for both compounds. Furthermore, the interaction between TQ and 3HQ was assessed using a checkerboard assay, which demonstrated a 100% synergistic interaction, with a fractional inhibitory concentration index (FICI) of less than 0.5 against the ESBL strains. Docking and molecular dynamics simulations indicated that TQ exhibits a strong binding affinity and interaction profile comparable to that of RPX-7063. In contrast, 3-hydrazinoquinoxaline-2-thiol targets a different active site, potentially enhancing thymoquinone's binding efficiency. Collectively, these compounds may effectively inhibit CTX-M-15, as evidenced by their docking scores and interaction profiles. Further investigations, including in vivo studies, are essential to validate these findings. This research suggests a promising strategy for developing more effective treatments for ESBL infections, emphasizing the need for in vivo validation.