The differences in the essential oil composition among the different production areas may be due to the developmental stages or variations in cultivation conditions of the plant, or as a result of structural or physiological modification of the plant caused by specific environmental factors (phenotypic plasticity). Thus, composition differentiation requires a detailed analysis using gas chromatography-mass spectroscopy (GC-MS) and the application of principal component analysis. Composition analysis via GC-flame ionization detection (FID) and GC-MS of the eessential oil (Zhang et al., 2010; Ma et al., 2010; Zhou et al., 2011) has been previously reported.