Variability in chemical composition and antimicrobial activity of essential oil of Rosa x damascena Herrm. from mountainous regions of Iran

Background: Essential oil of Rosa x damascena Herrm. is one of the most valuable and important raw materials for the flavor and fragrance industry. The cultivation of this plant has ancient origins, and Kashan was one of the first mountainous regions of Iran dealing with the cultivation of R. x damascena. In this study, both chemical composition and antimicrobial activity of different rose essential oils obtained from five mountainous areas of Kashan region (Maragh, Qamsar, Sadeh, Javinan, and Kamoo) has been investigated along with the influence of the environmental conditions on these properties.Results: Results showed that yield and chemical composition of essential oils obtained from Rosa x damascena were significantly affected by the collection area. In particular, the yield of oils varied from similar to 0.08 to similar to 0.132% and citronellol (36.70-9.18%), geraniol (12.82-0.47%), nonadecane (22.73-10.36%), heneicosane (31.7-11.43%), and 1-nonadecene (6.03-3.93%) have been detected as main compounds in all the plants collected, but at different concentrations depending on the collection area. The best fragrance and the highest yield were found in the oil from Kamoo area. Similarly to the chemical composition, the antimicrobial activity of the essential oils was affected by their origin, and essential oil obtained from plants collected from Kamoo area disclosed the highest antibacterial and antifungal efficacy. Its inhibition halos were 17.33 +/- 0.58 mm against Aspergillus brasiliensis, 15.67 +/- 0.58 mm against Staphylococcus aureus, and 12.33 +/- 0. 58 mm against Streptococcus pyogenes. Essential oils of R. damascena were also effective against Gram-negative Pseudomonas aeruginosa and they had a MIC value of 62.50 mu g/mL irrespective of the collection area (except the oil from Javinan area). On the contrary, the highest antifungal power against Candida albicans yeast was reached using the essential oil obtained from plants collected in Javinan region (MIC and MBC similar to 62.50 mu g/mL).Conclusions: Overall results underline the influence of environmental conditions of the different areas of Kashan region, on the chemical composition of and antimicrobial activity of the essential oils of Rosa x damascena. In addition, results disclosed that Kamoo seemed to be the most suitable area for the competitive cultivation of R. x damascena to the intensive production of aromatic flower oil and natural antimicrobial essential oils.