Antidermatophytic activity of volatile oil and nanoemulsion of Stenachaenium megapotamicum (Spreng.) Baker

Volatile oils have important biological properties, like antifungal activity. Several studies have investigated the ability of nanoparticulate systems as carriers of these substances in order to stabilize and reduce their volatility and improve their effects. The aims of this study were to analyze the chemical composition of volatile oil of Stenachaenium megapotamicum and to evaluate the antifungal activity of the pure oil and its nanoemulsion. The volatile oil obtained by hydrodistillation was analyzed by gas chromatography coupled to mass spectrometry and presented 52.6% of sesquiterpenes. Fokienol was the most abundant compound (24.4%), followed by 7-(isopentyloxy)-2H-chromen-2-one (17.9%), thymol (10.8%) and β-bisabolene (9%). The nanoemulsion was obtained by spontaneous emulsification and exhibited translucent appearance, pH 5.14, particle diameter of 210 nm and polydispersity of 0.369. Apart from volatile oil and nanoemulsion, thymol also was tested for antifungal activity. The volatile oil and thymol exhibited antidermatophytic activity, presenting selectivity against the filamentous fungi Epidermophyton floccosum, Scytalidium dimidiatum and Trichophyton rubrum. Significantly reduced minimal inhibitory concentration and minimal fungicidal concentration were observed for the nanoemulsion containing volatile oil of S. megapotamicum, when compared with the activity of pure oil and of thymol, demonstrating the ability of the nanoparticulate system to improve oil activity.