Piper cernuum Vell.: Chemical profile and antimicrobial potential evaluation

Abstract

In this study, the Piper cernuum Essential Oil (EOPC) was tested against bacterial and fungal strains using the microdilution method to evaluate its minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC), as well as its antibiotic modifying effect, in addition to observing the oils ability to cause fungal dimorphism and to generate an IC50 cell viability curve. The EO was obtained through hydrodistillation using a Clevenger-type apparatus with the dry leaves and analyzed by GC-FID, allowing the identification of 14 compounds, with the main compound being 4-epi-cis-dihydromarofuran (28.97%). An EOPC intrinsic activity was identified only against Candida albicans 4127 (IC50 56.851 μg/mL). Given the MIC results from the EOPC intrinsic activity against Staphylococcus aureus 10 at the concentration of 406 μg/mL, its association with fluconazole potentiated it’s antifungal action. The action of gentamicin was potentiated by the addition of the EOPC to Staphylococcus aureus 10 and Escherichia coli 06 strains, both with MIC < 40 μg/ml, however, when the EOPC was combined with other antibiotics against Staphylococcus aureus 10 they presented an antagonistic response. When the EOPC was tested with the antibiotic norfloxacin against the Gram-negative Escherichia coli 06 strain an antagonistic response was also found. The EOPC inhibited fungal dimorphism, reducing the virulence of these strains, with this effect being better than that of fluconazole. These results highlight the species as a promising source of active antimicrobial compounds.