Leaves of oregano (Origanumvulgare) and rosemary (Rosmarinus officinalis) (crop 2011) were provided by the Facultad de Ciencias Agropecuarias e Universidad Nacional de Cordoba (Cordoba,
Argentina). The essential oil was obtained by hydrodistillation using Clevenger type apparatus. 50 g of plant material (oregano or rosemary) was placed in the extraction chamber (1 L) and distillated for 1 h at 100?C. In this extraction process, the volatile compounds (essential oils) were removed by steam water from the plant material. The essential oils were condensate and collected in a glass recipient and were separated from the water because due to the different polarity and density. The essential oil extracted was stored in glass vial at ?18?C in darkness with the addition of sodium sulfate to eliminate residual moisture (Olmedo et al., 2012). This extraction process allowed obtaining volatile compounds with low boiling point (essential oils), especially terpenoids.