Growth inhibition and morphological alterations of Trichophyton rubrum induced by essential oil from Cymbopogon winterianus Jowitt ex Bor

Abstract

Trichophyton rubrum is one of the most common fungi causer of dermatophytosis, mycosis that affect humans and animals around the world. Researches aiming new products with antifungal activity become necessary to overcome difficulties on treatment of these infections. Accordingly, this study aimed to investigate the antifungal activity of essential oil from Cymbopogon winterianus against the dermatophyte T. rubrum. The antifungal screening was performed by solid medium diffusion method with 16 T. rubrum strains, minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined using the microdilution method. The effects on mycelial dry weight and morphology were also observed. Screening showed essential oil in natura inhibited all the tested strains, with inhibition zones between 24-28 mm diameter. MIC50 and MIC90 values of the essential oil were 312 μg/mL for nearly all the essayed strains (93.75 %) while the MFC50 and MFC90 values were about eight times higher than MIC for all tested strains. All tested essential oil concentrations managed to inhibit strongly the mycelium development. Main morphological changes on the fungal strains observed under light microscopy, which were provided by the essential oil include loss of conidiation, alterations concerning form and pigmentation of hyphae. In the oil presence, colonies showed folds, cream color and slightly darker than the control, pigment production was absent on the reverse and with evident folds. It is concluded that C. winterianus essential oil showed activity against T. rubrum. Therefore, it could be known as potential antifungal compound especially for protection against dermatophytosis.

Chemical composition and antifungal activity of essential oil from Eucalyptus smithii against dermatophytes

“…Minimum fungicidal concentration (MFC) was determined using the microdilution method (20) . Aliquots of 20µL from the wells that did not show growth in the MIC procedure were transferred to new 96-well plates containing 180µL of SDA.…”

“…Current treatments for dermatophytosis include synthetic antifungal drugs, which can give rise to adverse reactions and resistant strains if not administered properly (17) (18) (19) . Essential oils serve as an alternative treatment for dermatophytosis because most of these oils have some degree of antifungal activity owing to their lipophilic nature (20) . The antifungal activities need not be ascribed to the high content of a single chemical compound because synergistic effects among the major and minor components can occur.…”

Preparation, and Assessment of Antidermatophyte Activity of Miconazole–Urea Water-Soluble Film

“…DMSO-treated T. rubrum was used as a negative control. Alterations detected in the test fungal structures were recorded, photographed, and compared with the normal growth in the negative control group (Pereira et al, 2011;Song et al, 2018).…”

“…Several studies have investigated the effect of different drugs, either synthetic or natural products, on T. rubrum, but there are no reports about the use of miconazole/urea combination against the test fungus (Smijs et al, 2008;Pereira et al, 2011;Kingsbury et al, 2012;Aala et al, 2014;Song et al, 2018). Interestingly, Mady et al (2018) developed novel buccal mucoadhesive patches against Candida albicans, which have the ability to attach to the buccal cavity, exerting a local effect on the infected site.…”

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“…A mechanism of action based on impairment of the biosynthesis of ergosterol was recommended as also occurs with conventional azole antifungal drugs 52 . Pereira et al 53 through scanning electron microscopic observations showed that essential oil were able to damage the cell membrane and cell wall in a dose and time dependent manner. Park et al 54 analysed the mechanism of action of eugenol, a main compound in Syzygium aromaticum oil.…”