Zanthoxylum zanthoxyloïdes (Lam.) is used for some health purposes in Burkina Faso. However, human action threatened this species in its native environment and its regeneration is difficult by the way of population. The main focus of this study is to discriminate samples of zanthoxyloïdes from different plant populations in order to find good specimens for traditional medicine and thus contribute to the conservation of this species. Plant materials were collected from three study sites named Niangoloko, Orodara and Sidéradougou. Samples powder, mixed with potassium bromide was used for the Fourier-Transform Infrared Spectrometry (FTIR) analysis. Multivariate data analysis was performed to highlight differences in the spectral profile among plant organs. Then, vanillic acid characteristic signals in infrared were identified by using literature data. Results showed that leaf and stem bark spectra were significantly different (p < 0.001 and p < 0.05, respectively) among the study sites, while root bark spectra were almost identical (p = 0.19). Root bark and stem bark both indicated similar patterns under vanillic acid characteristic signals. The use of stem bark instead of roots can be a substitute for root to the sustainable management of this species in its native environment.

Many pathogenic bacteria produce virulence factors controlled by a mechanism of regulation named quorum sensing (QS). Inhibition of bacterial QS system is a more recent therapeutic approach to counterbalance the emergence of multi-drug resistant bacteria. This study aimed to assess the abilities of methanol extract from Guiera senegalensis galls and its isolated compound methyl gallate to quench the quorum sensing system. Methanol extract from galls of G. senegalensis at the concentration of 100 µg/ml demonstrated significant inhibitory effect on pyocyanin and violacein production respectively in Pseudomonas aeruginosa PAO1 and Chromobacterium violaceum CV026. Colum chromatography and recycling High Performance Liquid Chromatography (HPLC) of methanol extract from galls of G. senegalensis led to the isolation of one active quorum quenching compound. Different spectroscopic methods (MS and NMR) were used to elucidate the structure of this isolated compound as being the methyl gallate (MG). Methyl gallate at the final concentration of 12.5 µg/ml demonstrated good anti-QS activity by inhibiting violacein and pyocyanin production. Its low molecular weight and the capacity to interfere with the mechanism of QS make methyl gallate, an interesting candidate for development of drugs as an alternative to antibiotics to combat bacterial resistance.