Essential Oil Chemical Composition of Rosa corymbifera Borkh., Rosa phoenicia Boiss. and Rosa damascena Mill. from Lebanon

Essential oils of three Lebanese Rose species (Rosa corymbifera Borkh., Rosa Phoenicia Boiss. and Rosa damascena Mill.) were investigated, to assess their bioactive components after hydrodistillation, using a Clevenger-type apparatus. A GC/MS analysis of the oil content of Rose species led to the identification of 22, 46 and 30 components in each of R. damascena, R. corymbifera and R. Phoenicia, respectively, representing 83.4 %, 72.9 % and 84.7 % of the total EO of the corresponding Rose species. The EOs chemical profile analysis showed that the main components of R. corymbifera (heptacosane (14.8 %), tricosane (10.6 %), pentacosane (8.6 %), nonacosane (8.6 %) and heneicosane (5.6 %)) and of R. Phoenicia (heptacosane (17.1 %), tricosane (12 .9 %), heneicosane (12.3 %), docosane (12.1 %) and cycloeicosane (7.6 %)) were hydrocarbons. While hydro- carbons were also identified in R. damascena (nonadecane (12.4 %) and heneicosane (8.1 %)), they were not its most abundant constituents. The major component of R. damascena was phenethyl alcohol (28.5 %), a benzenoid compound, also identified in R. phoenicia (5.1 %). Moreover, an oxygenated terpene (beta-citronellol (13.2 %)) was also identified in R. damascena. Since R. damascena is largely cultivated in Lebanon, a comparative study of R. damascena EO was performed on a group of samples collected from different locations (ours and data previously published), to identify the presence of any chemical polymorphism according to the geographical location. GC/ MS analysis together with principal component analysis (PCA) highlighted six different chemotypes for R. damascena EO: citronellol, geraniol, nerol, nonadecane, phenyl ethyl alcohol and heneicosane. This chemical variability suggests the involvement of abiotic and biotic factors that need to be further investigated.