Investigation of Melissa officinalis L. Essential Oil for Antifungal Activity against Cladosporium carrionii

Abstract

Cladosporium carrionii is considered the most important pathogenic species of genus because of the numerous cases of disease which causes in the world. Due to its antifungal resistance, these fungal infections are difficult to treat. Given the broad biological activity displayed by natural products, essential oils obtained from plants are often investigated to determine their antimicrobial activity. Aims: Therefore, we identified components of Melissa officinalis L. essential oil, investigating in vitro antifungal activity against strains of C. carrionii. Methodology: Identification of the chemical composition of the oil was performed by gas chromatography coupled to a mass spectrometer (GC-MS). The antifungal activity of M. officinalis L. essential oil was investigated against 08 strains of C. carrionii determining minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), effects on mycelial growth, and conidial germination. Results: The GC-MS results revealed 4 major components; geranial (52%), citral (38.90%), trans-β-caryophyllene (1.22%), and germacrene D (0.84%). M. officinalis L. essential oil inhibited the growth of all (100%) of the strains of C. carrionii tested. The MIC and MFC were established at 256 µg/ml. Inhibition of radial mycelial growth began at 128 µg/ml (MIC/2), and at both 2 x MIC and 4 x MIC the inhibition was complete. We also observed significant conidial germination inhibition at all concentrations when compared to the control (P<0.05). The inhibition increased with concentration so that at 2 x MIC complete (100%) conidia germination inhibition was observed. Conclusion: Finally, our study results point to M. officinalis L. essential oil as a potential antifungal agent against C. carrionii.