Determination of volatile components in Iranian Rosa hemisphaerica

Abstract

composition. The flowering parts of R. hemisphaerica yielded 0.1% v/w of a colorless oil which was determined by a gravimetric method and calculated as a percentage of the mass of starting dry plant material. In this oil, 27 compounds, which represent about 99.4% of the total composition, were identified and are listed in Table 1 with their percentage. Constituents are listed in order of their elution from a DB-1 column. The major constituents are heneicosane (32%), nonadecane (30%), 9-nonad ecene (10.5%), and tricosane (8.3%). We made a comparison of this species of rose with the closely related Rosa damascena Mill. The major components of R. hemisphaerica and several R. damascena from China [11], Turkey [12], Bulgaria [13], and the Himalayas [14] are listed in Table 2. As can be seen in Table 2, the essential oils of R. damascena contain large amounts of citronellol, nerol, or geraniol, which cause this species to be odorous. Except nonadecane, the amount of other normal hydrocarbons in R. damascena oils was small. R. hemisphaerica essential oil contains only 2% of geraniol; instead this oil is rich in normal hydrocarbons such as nonadecane, nonad ecene, heneicosane, and eicosane. GC analysis of oil was conducted using a Thermoquest-Finnigan Trace GC instrument equipped with a DB-1 fused silica column (60 m × 0.25 mm, film thickness 0.25 μm). Nitrogen was used as the carrier gas at the constant flow of 1.1 mL/min. Oven temperature was held at 60°C for 3 min and then programmed to 250°C at a rate of 5°C/min, and then held at 250°C for 10 min. The injector and detector (FID) temperatures were kept at 250°C and 280°C, respectively. GC-MS analysis was carried out on a Thermoquest-Finnigan Trace GC-MS instrument equipped with a DB-1 fused silica column (60 m × 0.25 mm, film thickness 0.25 μm) and operating under the same conditions as described a bove. The quadrupole mass spectrometer was scanned over the 45‐465 amu with an ionizing voltage of 70 eV and an ionizing current of 150 μA.