Antibacterial activity and metabolomic profile of Zanthoxylum caribaeum Lam. aqueous extract against...

Improved antimicrobial medication or treatments are solutions that need to be combined to limit the impact of antibiotic resistance. Plants have historically been the source of many effective medicines. Zanthoxylum caribaeum is typically found in tropical regions and known for its wide range of plant metabolites that can be attributed to antibacterial activity. The aim of this study was to identify the metabolites potentially involved in the antibacterial activity of Z. caribaeum against resistant bacteria. The antibacterial effect of dried microwave-treated aqueous extracts of Z. caribaeum was tested in vitro against Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa. Determination of the minimum inhibitory concentration (MIC) confirmed the inhibitory effect observed by the disc method. This showed that Z. caribaeum had a more pronounced effect on methicillin-resistant S. aureus (MRSA) at a high concentration with a MIC value of 1.6 × 10⁴ µg/mL, reflecting a weak activity. In parallel, this study provided a global characterization of Z. caribaeum aqueous extract by GC×GC-TOFMS. The 24 most abundant compounds tentatively identified in the derivatized dried aqueous extract of Z. caribaeum, such as 4-hydroxybenzyl alcohol and 1-monopalmitin, are known precursor molecules for important biological functions and proteins. In addition, the low dose inhibitory effect of Z. caribaeum aqueous extract makes it a candidate for phytochemical isolation of these molecules and improvement of their antibacterial activity.