Extensive Integrated In vitro and Computational Investigation of the Antibacterial Activity of 4-bromo-2-methylphenyl Isothiocyanate against Nine Bacterial Pathogens
Nichan Boruah, Bendangtula Walling, Basanta Singha, Partha Pratim Gogoi, Penlisola Longkumer, Pranjal Bharali, Upasana Bora SinhaIntroduction/Objectives:
Antibacterial resistance represents a significant global health challenge, leading to prolonged infections, increased healthcare costs, and elevated mortality rates. Despite ongoing research efforts, the discovery of novel antibacterial agents remains limited, often focusing on preliminary screening rather than fully exploring molecular potential. Structurally simple small molecules constitute a promising yet underexplored source of new therapeutics. Among these, isothiocyanates have demonstrated diverse biological activities but remain insufficiently investigated for antibacterial applications. The present study aimed to evaluate the antibacterial potential of 4- Bromo-2-methylphenyl isothiocyanate (4-BMPI) and to explore its possible mechanism of action through integrated in vitro and in silico approaches.
Methods:
The antibacterial activity of 4-BMPI was assessed against nine Gram-positive and Gramnegative bacterial strains. In vitro analyses included agar well diffusion assays, determination of minimum inhibitory concentration, time-kill kinetic studies, and membrane permeability assays. Mechanistic investigations were conducted using crystal violet uptake assays, UV-absorbing material leakage measurements, Fourier-Transform Infrared (FTIR) spectroscopy, and Field Emission Scanning Electron Microscopy (FESEM). Additionally, physicochemical and ADMET properties were predicted computationally. Molecular docking studies were performed using Molegro Virtual Docker to evaluate binding interactions with selected bacterial protein targets.
results:
The investigation revealed that 4-BMPI possesses broad-spectrum effectiveness, with MIC values ranging from 0.25 to 1 mg/mL and a profile of rapid bactericidal action. Mechanistic studies confirmed that 4-BMPI successfully disrupts membrane integrity and induces significant morphological changes in the tested bacterial cells. Complementary ADMET and physicochemical analyses indicated that the compound possesses favourable drug-like properties. Additionally, molecular docking results showed stable and specific interactions with conserved bacterial residues, suggesting a significant binding affinity that supports its biological efficacy.
Results:
4-BMPI demonstrated broad-spectrum antibacterial activity, with MIC values ranging from 0.25 to 1 mg/mL. Time-kill studies indicated rapid bactericidal effects. Membrane permeability assays showed increased crystal violet uptake and leakage of intracellular components, suggesting disruption of bacterial membrane integrity. FTIR and FESEM analyses further confirmed structural and morphological damage to bacterial cells following treatment. Computational analyses revealed favourable drug-like and ADMET properties. Molecular docking studies indicated stable binding interactions with conserved bacterial residues, supporting potential molecular-level interactions.
Discussion:
The findings suggest that 4-BMPI exerts antibacterial effects primarily through membrane disruption, leading to cellular damage and bacterial death. The compound’s structural simplicity, combined with its observed biological activity and favourable predicted pharmacokinetic properties, highlights its potential as a lead scaffold. While docking results provide supportive molecular insights, further mechanistic and safety studies are warranted.
conclusion:
These findings establish 4-BMPI as a promising lead scaffold for the development of next-generation antibacterial drugs. By combining structural simplicity with strong biological efficacy and favourable pharmaceutical properties, 4-BMPI offers a viable foundation for future drug design. This study underscores the importance of exploring underexplored bioactive compounds in the ongoing effort to expand the global antibacterial pipeline.
Conclusion:
This study establishes 4-BMPI as a promising antibacterial lead candidate with broadspectrum activity and a membrane-targeting mechanism. Its structural simplicity and moderate biological efficacy support its potential for further optimization and development as a next-generation antibacterial agent.