Isolation of the volatile oil from Satureja thymbra by supercritical carbon dioxide extraction: chemical composition and biological activity.

Satureja thymbra L. is well known in Italy by the popular name of "Santoreggia sarda". It grows only in Sardinia and nowadays it is restricted to the slope of the Colle San Michele in Cagliari. The composition of the aromatic extracts obtained by supercritical CO2 and by hydrodistillation and their antifungal activity is reported. The collected extracts were analyzed by GC-FID and GC-MS methods. No significant differences were observed in the composition of the volatile extracts depending on the extraction method. The results showed the presence of thymol, gamma-terpinene, beta-caryophyllene, p-cymene, carvacrol and borneol as main components. The minimal inhibitory concentration (MIC) and the minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the oils against Candida albicans, C. tropicalis, C. krusei, C. guillermondii, C. parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, T. mentagrophytes, T. mentagrophytes var. interdigitale, Trichophyton rubrum, T. verrucosum, Microsporum canis, M. gypseum, Epidermophyton floccosum, Aspergillus niger, A. fumigatus and A. flavus. The volatile extracts revealed a wide-spectrum antifungal activity. They were fungicidal and similarly potent against yeasts, dermatophyte and Aspergillus stains, with MICs ranging from 0.16 to 0.32 pL x mL(-1).