Antifungal activity of the essential oil of Origanum syriacum L

The volatile oil of the Lebanese Za'atar (Origanum syriacum L.) was characterized for its thymol and carvacrol content using gasliquid chromatography. These two compounds constituted the major components of the oil and were present in equal proportions of 30% in the volatile oil extracted from the leaves and shoot tips of the Origanum plant during the preflowering stage. The percentage of carvacrol in the essential oil increased to 62% after flowering and maturation, while the concentration of thymol decreased to 14%. Origanum oil extracted from plants collected during midseason was evaluated for its antifungal activity against Aspergillus niger, Fusarium oxysporum, and Penicillium species. The oil exhibited strong inhibitory action against the three fungi tested. The minimum inhibitory concentration (MIC) of the oil was found to be 0.1 μl/ml of yeast extract sucrose broth for the fungi tested. ©, International Association of Milk, Food and Environmental Sanitarians.