Content and Chemical Profile of Essential Oil
from Eucalyptus Fresh and Dry Leaves
Laurine Cristina Paulo da Silva, Elisabeth Alves Duarte Pereira, Erica Prilips Esposito, Ana Flávia Carvalho da Silva, Tainá de Sá Farias, Marcela de Souza Alves, André Marques dos Santos and Marco Andre Alves de Souza*
Laboratory of Medicinal and Aromatic Plants and Laboratory of Plant Biochemistry, Biochemistry Department, Chemistry Institute, Federal Rural University of Rio de Janeiro, Brazil
Submission: March 23, 2019; Published: April 17, 2019
*Corresponding author: Marco Andre Alves de Souza, Laboratory of Medicinal and Aromatic Plants and Laboratory of Plant Biochemistry, Biochemistry Department, Chemistry Institute, Federal Rural University of Rio de Janeiro, Brazil
How to cite this article: Laurine Cristina Paulo da Silva, Erica Prilips Esposito, Marco Andre Alves de Souza, et al. Content and Chemical Profile of
Essential Oil from Eucalyptus Fresh and Dry Leaves. Agri Res& Tech: Open Access J. 2019; 21(2): 556154. DOI: 10.19080/ARTOAJ.2019.21.556154
The essential oils yield, and chemical composition can vary depending on several factors, among them the raw material condition. For this reason, the objective of the present work was to compare the yield and chemical profile of Eucalyptus essential oils [Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson], obtained from the dried and fresh leaves by hydrodistillation method. The essential oils were obtained after one hour of hydrodistillation, submitted to gravimetric analysis to determine the yield (%, w/w) and GC-FID and GC-MS analysis for chemical profile evaluation. The results showed that the yield of essential oil was higher in the dry leaves, which in turn, also showed changes in essential oil profile.
The genus Corymbia belongs to the family Myrtaceae and comprises tree species popularly called eucalyptus, which have common characteristics such as rapid growth and productivity, great adaptability, and have different purposes and uses for the industrial, commercial and popular economy sectors . Eucalyptus diversity center is in Australia and some neighboring islands, where more than 700 species have been identified and subdivided into some genera [2,3]. However, it is currently distributed throughout Europe, Africa, Asia and the Americas.
The main product obtained from eucalyptus, is the wood that can be used for the production of coal, for the civil construction like poles and fences and for the obtaining of celullose and paper . The leaves show a diversified aroma that allows the obtaining of essential oils, which constitutes a secondary economic activity for the commercial eucalyptus crop .
Essential oils are products extracted from plants through techniques involving steam distillation, hydrodistillation and also by citrus fruit pericarp expression . In the eucalyptus volatile substances are secreted in schizolysigenous cavity, present in abundance in the leaf mesophyll [6,7]. The content and quality of the essential oils obtained from the leaves can vary according to genetic factors, adaphoclimatic and ecological conditions and according to the management adopted after the harvest, as well as, the method
adopted during the extraction [3,8-12]. The essential oil contents in the leaves of Corymbia citriodaora varying from 0.6 to 5.9%  and a chemical profile rich in oxygenated monoterpenes, mainly citronellol and citronellal [10,3,14].
All procedures were performed at the Laboratory of Medicinal and Aromatic Plants in Federal Rural University of Rio de Janeiro. Eucalyptus, Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson, was collected in Federal Rural University of Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil in August (winter) 2016, identified by comparison with existing herbarium specimens of the Biology Institute (UFRRJ). The soil is classified in the haplic planosol class, the mean temperatures in August was 22.7 °C, with rainfall of 33mm and relative humidity values of 68.50% .
After harvesting, part of the leaves was separated and dried in a forced-air oven (Eletrolab EL 403, Brazil) at 37 °C for 48 hours, when they reached constant weight. Essential oils from fresh or dried leaves of eucalyptus were obtained by hydrodistillation in a Clevenger apparatus for one hour. The hydrodistilled fraction, containing water and essential oil, was collected and dried with anhydrous Na2SO4. The gravimetric analysis to obtain the essential oil yield (%, w/w) was performed based on dry or fresh weight
according to the following equation: OE% = (OEW * 100) / LW.
Where: EO%, EOW and LW are essential oil yield, essential oil
weight and leaf weight respectively.
GC analysis was carried out with a Hewlett-Packard 5890
II apparatus (Palo Alto, USA) equipped with a flame ionization
detector (FID), and a split/splitless injector at a 1:20 split ratio
was used to separate and detect essential oil constituents.
Substances were separated into a VF-5ms fused silica capillary
column (30m × 0.25mm i.d., film thickness 0.25μm, Agilent J&W).
The oven, injector and detector temperatures were programmed
as reported by Adams . The carrier gas used was He (1mL/
min). Injected volume was 1μL at a 1:20 split ratio. Percentage of
essential oil compounds was calculated from the relative area of
each peak analyzed by FID. Essential oils were also analyzed with
a GC/MS QP-2010 Plus instrument (Shimadzu, Japan). Carrier
gas flow, capillary column and temperature conditions for GC/
MS analysis were the same as those described for GC/FID and
reported by Adams . Mass spectrometer operating conditions
were ionization voltage of 70eV, mass range of 40-400m/z and
0.5scan/s. The compounds’ retention indexes were calculated
based on co-injection of samples with a C8-C20 hydrocarbon
mixture, as reported by van Den Dool and Dec Kratz .
Constituents were identified by comparison of their mass spectra
with the NIST library (2008) and with those reported by Adams
Table 1 shows the eucalyptus essential oils chemical profile
obtained from fresh and dried leaves, as well as, the essential oils
yield (%, w/w). The main substances identified were citronellal
(76.1 and 79.5%) and citronellol (15.9 and 14.3%) oxygenated
monoterpenes, respectively, in the essential oils of fresh and
dried eucalyptus leaves. The main difference observed in the
essential oils chemical profile was the absence of the fenchene
(monoterpene hydrocarbon) in the dried leaves essential oil and
their presence at 1,5% in the fresh leaves essential oil. The yield of
essential oil obtained from dried leaves (2.02%, w/w) was higher
than that obtained from fresh leaves (0.89%, w/w) of eucalyptus.
As the eucalyptus essential oil is a by-product of the crop,
the adopted management does not always follow an appropriate
procedure aiming at a quality standard adequate to the industrial
sectors requirements. If the one hand, the leaves drying process
led to an increase by 226% in essential oil yield, on the other, the
change in the chemical profile led to an increase of citronellal by
10% and the suppression of fenchene in the essential oil were
observed. It is necessary to verify if these chemical changes imply
loss or gain of quality from the commercial point of view.
Previous report showed that the essential oils contents
varying from 0.6% to 5.9% in dry leaves of Corymbia citriodora
. However, the variation in essential oil yield, as observed in
this work, is relates to the drying process, and similar results
were reported by Zrira and Benjilali . Regarding the essential
oils chemical profile, several works showed predominance of
oxygenated monoterpenes, with citronellal and citronellol being
the major substances [10,13,14,18,19], similar to what we present
in the present work. Other works also showed small variation
in the profile of essential oil due to drying, although it did not
drastically alter the quality of the same [3,12].
From the purely economic point of view, the drying process
reduces the energy spent during the essential oil extraction,
considering that the capacity of raw material allocation in
distillation tank is defined by weight and the water reduction in
the vegetal tissue allows the allocation of higher amount of raw
From the present work it can be concluded that the drying
process did not promoted significant changes in the essential
oil composition, based on information available in the literature.
Thus, the condition indicated for the Corymbia citriodora essential
oil extraction involves the drying leaves previously, under the
conditions presented in this work.
Funding: This study was financed in part by Fundação
de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)
- Finance Code E-26/110.746/2012 and by Coordenação de
Aperfeiçoamento de Pessoal de Níve Superior - Brazil (CAPES) -
Finance Code 001. We gratefully acknowledge the Postgraduate
Program in Chemistry of Federal Rural University of Rio de Janeiro.