|Authors: ||M.J. Jordán, V. Lax, C. Martínez, M. Aouissat, J.A. Sotomayor|
|Keywords: ||rosemary, essential oil, volatile profile, GC-MS, geographical variation|
The quantitative chemical composition of Rosmarinus officinalis L. essential oil depends, as has been reported in several publications, on the geographical origin of the species.
Major components identified in the essential oil, which define the chemotype of these plants, are camphor, 1,8-cineol and α-pinene.
However, the intraspecific variability detected among plants belonging to a reduced geographical area, as occurs in the Region of Murcia (11,313 km2), implies the necessity of establishing the existence of different chemotypes in the growing area, and defining these chemotypes and their relation to the specific climatic conditions.
On these bases, 31 wild rosemary populations (a total of 152 individual plants) were prospected and analyzed.
Chromatographic analysis allowed for the detection of 3 different major chemotypes, including: 1,8-cineol-α-pinene-camphor (representing a 18.42% of the total plants analyzed); camphor-1,8-cineole-α-pinene (17.76%); and 1,8-cineol-camphor-α-pinene (13.82%). Minor chemotypes characterized correspond to: α-pinene-1,8-cineol-camphor (4.61%); α-pinene-camphor-1,8-cineol (3.95%); and camphor-α-pinene-1,8-cineol (3.95%). It is interesting to note the existence of some plants with an essential oil rich in components such as verbenone (13% of the oil), borneol (11%) and camphene (10%). For these shrubs, the essential oil chemotype is defined by the major components mentioned above plus these minor components.
The effect of altitude of the growing area on the essential oil chemotype definition was also determined.
In areas located from sea level to 1000 m a.s.l., the major component identified in the oil was 1,8 cineol (representing 49% of the plants analyzed), followed by camphor (27%). However, this situation changes in areas located between 1000 and 1500 m a.s.l., where the percentage of shrubs with camphor-1,8-cineol, and 1,8-cineol-camphor chemotypes was similar (40 and 38.5% respectively).
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