Chemical Variation in the Essential Oil of Iranian Rosa damascena Landraces under Semi-arid and Cool Conditions

Abstract

In present study, essential oil content and compositions of 49 Iranian landraces of Damask rose (Rosa damascena Mill.) was investigated. Essential oils were isolated with distillation method and component composition was determined with gas chromatography–mass spectrometry (GC/MS). Twenty main compounds were identified in the essential oil representing about 90% of the total oil. The major components were found to be n-nonadecane (with seasonal range of 32.4-36.1%), n-heneicosane (20.3-22.1%), citronellol (6.6-10.3%), n-hexadecanol (6.4-6.7%) and n-tricosane (5.9-7.0%). The percentages of citronellol and geraniol as the two important compounds of the rose oil quality in 2008 were more than their percentages in 2007. Therefore, it can be inferred that dry conditions increased the aliphatic compounds percentages and reduced alcoholic compounds in the rose oil. Despite the differences in origin sites, climates and ecological conditions among landraces, the results of cluster analysis (CA) revealed that all of the landraces of Damask rose with exception of KB1 and AK1 showed more than 90% similarity in their major oil composition. The result of principal component analysis (PCA) revealed that the landraces with the highest percentage of citronellol and geraniol components usually show extreme values (positive or negative) of PC1 and PC2.