6-Methoxy-2-benzoxazolinone (MBOA) and 2-benzoxazolinone (BOA) are naturally occurring plant allelochemicals with reported antimicrobial properties, but their activity against drug-resistant Salmonella Typhi has not been investigated. This study evaluated their in vitro efficacy against clinical S. Typhi isolates and assessed their therapeutic potential in a murine S. Typhimurium infection model. Both compounds exhibited drug-like physicochemical characteristics and were predicted to fall under toxicity class 4. MIC values ranged from >0.25 to >1 mg/mL across the tested isolates, indicating moderate antibacterial activity. MBOA and BOA also demonstrated concentration-dependent inhibition of biofilm formation and partial disruption of established biofilms at MIC and MIC × 2 levels. In silico docking showed strong affinity for bacterial dihydrofolate reductase (DHFR), and both compounds produced measurable inhibition of the enzyme at 0.01–0.05 mg/mL, providing supportive but not conclusive evidence for DHFR targeting. In vivo, treatment with either compound reduced fecal bacterial shedding, lowered intestinal and hepatic colonization, and preserved intestinal morphology compared with untreated infected controls. Together, these findings indicate that MBOA and BOA possess measurable anti-Salmonella activity with in vivo therapeutic potential, warranting further mechanistic validation and optimization for antimicrobial development.
Saren et al. (2026) studied this question.