Characterization, antifungal activity, and possible action mechanism of Melissa officinalis essential oil against Candida spp. and Cryptococcus neoformans strains.

This study aimed to characterize Melissa officinalis essential oil (EOMO) from a region in Northeast Brazil and evaluate its antifungal activity against Candida and Cryptococcus neoformans, by analyzing its action mechanism. EOMO was characterized using gas chromatography-mass spectrometry and the main chemical compounds were Geranial (14.10%) and (Z)-Nerolidol (17.75%). The broth microdilution assay was used to determine the minimum inhibitory concentration (MIC) against strains of Candida albicans, Candida parapsilosis, Candida krusei, Candida auris (MIC raging from 256 to 26.7 µg ml-1) and C. neoformans (MIC ranging from 64 to 32 µg ml-1). Flow cytometry and comet assays were employed to investigate EOMO's mechanism of action, which might be related to an increase in the production of reactive oxygen species and damage to fungal DNA. The chemical composition of EOMO from Northeast Brazil showed a higher content of (Z)-Nerolidol and has significant antifungal potential.