The Antibacterial Activity, Acute Toxicity, and Antibacterial Mechanism of 2,6-Dimethyl-4-aminophenol Hydrochloride

Objective: The problem of bacterial resistance has attracted increasing attention, and the development of novel antibacterial agents is paramount in addressing this challenge. 2,6-Dimethyl-4-aminophenol hydrochloride (DMAPH) is a known compound with several reported applications, but no antibacterial effects have been described to date. The objective of this study was to investigate the antibacterial activity of DMAPH, examine its mechanism of action against S. aureus, and evaluate its oral acute toxicity in mice to assess its potential as an antibacterial agent. Methods: The antibacterial activity of DMAPH was evaluated against six bacterial species. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. The effects of DMAPH on cell membrane and cell wall permeability of S. aureus were examined through the leakage of intracellular components (nucleic acids, proteins, potassium ions, and alkaline phosphatase). Oral acute toxicity was assessed in mice, and the LD₅₀ value was calculated. Results and Discussion: DMAPH exhibited significant antibacterial activity, with the strongest inhibition observed against S. aureus and S. epidermidis. MIC and MBC values were 4.88 and 9.76 μg/mL, respectively. DMAPH disrupted the cell membrane and wall integrity of S. aureus, leading to leakage of cellular components and bacterial death. The oral acute toxicity test in mice yielded an LD₅₀ value of 1052 mg/kg (95% confidence interval: 972–1139 mg/kg), indicating low toxicity. These findings suggest that DMAPH is a promising antibacterial agent with a membrane-targeting mechanism. Conclusions: DMAPH demonstrates notable antibacterial activity and low acute toxicity, supporting its potential as a candidate for antibacterial drug development. However, current data are insufficient to confirm its in vivo efficacy, and further studies are required to validate its therapeutic potential.