Pilosocereus pachycladus F. Ritter, Cactaceae, popularly known as “facheiro”, is used as food and tradi-tional medicine in Brazilian caatinga ecoregion. The plant is used to treat prostate inflammation andurinary infection. The present work reports the first secondary metabolites isolated from P. pachycladus.Therefore, the isolated compound 4-hydroxy-3,5-dimethoxy benzaldehyde (syringaldehyde) was evalu-ated as modulator of Staphylococcus aureus pump efflux-mediated antibiotic resistance. The isolation ofcompounds was performed using chromatographic techniques and the structural elucidation was carriedout by spectroscopic methods. In order to evaluate syringaldehyde ability to modulate S. aureus antibi-otic resistance, its minimum inhibitory concentrations (μg/ml) was first determinate, then, the testedantibiotics minimum inhibitory concentrations were determined in the presence of the syringaldehydein a sub-inhibitory concentration. The chromatographic procedures led to isolation of twelve compoundsfrom P. pachycladus including fatty acids, steroids, chlorophyll derivatives, phenolics and a lignan. Thesyringaldehyde did not show any antibacterial activity at 256 μg/ml against S. aureus. On the other handthe compound was able to reduce the antibiotic concentration (tetracycline, norfloxacin, ethidium bro-mide) required to inhibit the growth of drug-resistant bacteria, showing the ability of syringaldehyde ofinhibiting the efflux pump on these bacteria.
de Brito-Filho, S. G., Maciel, J. K. da S., Teles, Y. C. F., Fernandes, M. M. M. de S., Chaves, O. S., Ferreira, M. D. L., … de Souza, M. de F. V. (2017). Phytochemical study of pilosocereus pachycladus and antibiotic-resistance modifying activity of syringaldehyde. Brazilian Journal of Pharmacognosy, 27(4), 453–458. https://doi.org/10.1016/j.bjp.2017.06.001