3. Results and discussion
3.1. Yield and chemical composition of essential oil
The EO was obtained by hydrodistillation from air-dried
P. graveolens aerial parts with a yield of 0.15% (v/w).
The rose geranium oil obtained is liquid and has yellowishgreen
colour. It has a strong rose scent with a less pronounced
mint note. Therefore, this oil may be valuable for the flavouring of
foods.
The EO was analysed by GCeMS. Qualitative and quantitative
analyses of the oil volatile profiles are listed in Table 1 according to
their elution order. In total, 45 compounds constituting 94.21% of
the essential oil have been identified. Results showed that citronellol
(30.2%), citronellyl formate (9.3%), geraniol (7.6%) and guai-
6,9-diene (5.4%) were found to be the major compounds in the oil
with minor amounts of isomenthone (4.1%) and menthone (3.6%).
Other components were found in less quantity (<3%). Linalool
which is present in 3.2% is an important constituent in fragrances
because of its pleasing aroma.
The rose geranium EO consisted mainly of monoterpenic alcohols
(41.2%), monoterpenic esters (23%) and sesquiterpenic hydrocarbons
(13.9%) (Table 2).
The market value of the essential oil is determined by terpenoid
composition: in particular, besides geraniol, citronellol, linalool,
and their esters, isomenthone, the sesquiterpenoid hydrocarbon
guaia-6,9-diene, and alcohol 10-epi-g-eudesmol play a key role, as
they allow to distinguish between oils of different origin, and
different varieties and quality (Lis-Balchin, 2002).
In our study, it appears that EO of rose geranium analysed could
be therefore classified as ‘‘citronellol chemotype”. Comparing the
composition of this oil with the data published by Rodolfo Juliani
et al. (2006), it was concluded that the composition of the oil was
similar to Chinese oils, with the same content of guaia-6,9-diene
and the absence of 10-epi-y-eudesmol. This oil is characterized by
high levels of citronellyl formate (9.3%), 6,9 guaia-6,9-diene (5.4%)
and trace amounts of 10-epi-y-eudesmol (0.88%) (Table 2) while
the Bourbon and Egyptian geranium oils contained high levels of
10-epi-y-eudesmol and traces of guaia-6,9-diene.
In agreement with results obtained by other authors, the chromatographic
analysis of rose geranium EO showed that citronellol
was the component present in the greatest percentage (Araya et al.,
2006; Gomes et al., 2007; Jalali-Heravi, Zekavat, & Sereshti, 2006).
Regarding other components, our results diverge from those
published by other authors (Rodolfo Juliani et al., 2006; Saxena
et al., 2004).
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