Effect of essential oil of the leaves of Eucalyptus globulus on heamatological parameters of wistar rats

Abstract

The study was designed to evaluate the effect of essential oil extract of Eucalyptus globulus on haematological parameters of wistar rats. Twenty-five adult wistar rats weighing between 80 to 130 g were used. The rats were divided into five groups; with group one as the control group. Increasing doses (12.5, 25.0, 50.0, 72.5 mg/ml) of the extract were administered orally daily to the other four groups for a period of four weeks. The animals were sacrificed and the blood collected for haematological parameters using automated haematological analyzer K-X-21 machine. The results indicate significant increases in level of Haemoglobin (Hb), White Blood Cell (WBC), and Red Blood Cell (RBC) but a decrease in the levels of the Mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC). The study confirmed that extract oil of eucalyptus globulus have some significant effects on haematological parameters of the wistar rats and these effects are dose dependent.

Full text

African Journal of Biochemistry Research Vol. 6(4), pp. 46-49, 29 February, 2012
Available online at http://www.academicjournals.org/AJBR
DOI: 10.5897/AJBR11.068
ISSN 1996-0778 ©2012 Academic Journals
Full Length Research Paper
Effect of essential oil of the leaves of Eucalyptus
globulus on heamatological parameters of wistar rats
OYESOMI, Tajudeen Oyesina1*, AJAO, Moyosore Salihu2, OLAYAKI, luquman Aribidesi4 and
ADEKOMI, Damilare Adedayo3
1Department of Anatomy, Kampala International University, Dar es Salaam, Tanzania.
2School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand,
Johannesburg, South Africa.
3Department of Anatomy, Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin, Ilorin,
Kwara State.
4Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin, Ilorin,
Kwara State.
Accepted 9 January, 2012
The study was designed to evaluate the effect of essential oil extract of Eucalyptus globulus on
haematological parameters of wistar rats. Twenty-five adult wistar rats weighing between 80 to 130 g
were used. The rats were divided into five groups; with group one as the control group. Increasing
doses (12.5, 25.0, 50.0, 72.5 mg/ml) of the extract were administered orally daily to the other four groups
for a period of four weeks. The animals were sacrificed and the blood collected for haematological
parameters using automated haematological analyzer K-X-21 machine. The results indicate significant
increases in level of Haemoglobin (Hb), White Blood Cell (WBC), and Red Blood Cell (RBC) but a
decrease in the levels of the Mean corpuscular volume (MCV), mean corpuscular hemoglobin
concentration (MCHC). The study confirmed that extract oil of eucalyptus globulus have some
significant effects on haematological parameters of the wistar rats and these effects are dose
dependent.
Key words: Eucalyptus globulus, oil extract, haematological parameters, wistar rats.
INTRODUCTION
Man in solving its numerous medical challenges have for
ages depends on his immediate environment taking
advantages of nature provisions of it beauty for live and
survival. They have learnt to depend on plants and in
some cases animals in providing solutions to the myriad
of their health problems (Oliver, 1960). However, the
increasing use of plants for the therapeutic and medicinal
use warrants an adequate scientific investigation to
confirm the suitability of plants or otherwise for the
purpose for which they are used. Most of these medicinal
plants are taking as vegetables, smoked leafs as
tobacco, while the stems and roots are sometimes
cooked for drinking.
*Corresponding author. E-mail: drstoyesomi@yahoo.com or
oyesina1@gmail.com. Tel: +255-653971790, +255-778287588.
Eucalyptus globulus is an ever green tree 40 to 70 m tall
(Little, 1983) widely planted in the sub tropics. Its roots,
stem, leaves and seed have been widely used in
traditional folk medicine in many parts of West Africa
countries. The plant fresh leaves are sometimes eating
as vegetables, while the dry leaves were often smoked
as cigarettes, in this case, for asthma treatment while the
oil is used in the form of an aperitif as a digestive
(Brooker et al., 1999). The stems and roots are cooked
as medicinal agents across different ethnics groups
within the country. The medicinal uses of Eucalyptus are
in the treatment of abscess, arthritis, boil, bronchitis,
burns, catarrh, diabetes, and dysentery (Watt et al., 1962;
Duke and Wain, 1981; List and Horhammer, 1969). It is
also to be useful in the various treatments of lung
ailment, malaria, bladder and liver infection (Boukef et al.,
1976). However, the mechanisms by which extract of E.
globulus exert it all these activities are not well

understood. The chemical composition of E. globulus are
eucalyptol (cineol), terpineol, sequiterpene, alcohol,
aliphatics aldehyde, isoamyl alcohol, ethanol and
terpenes (Morton, 1981).
Erythrocytes (red blood cell) which are anucleate
matured cells are loaded with the oxygen carrying
proteins known as haemoglobin. The normal concen-
tration of erythrocytes in adult blood is approximately 3.9-
5.5 million per micro litre in women and 4.1 to 6 million
per micro litre in men (Junqueira et al., 2005). Human
erythrocytes life span in circulation ranges from 90 to 120
days, while the worn out red blood cells are removed
from the circulation by macrophages of the spleen and
bone marrows. The effects of Eucalyptus globules on
haematological parameters are not documented.
Leukocytes (white blood cells) are involved in the
cellular and humoral defense mechanisms of the body
are responsible for fight against foreign agents. The
estimated total number of leukocytes in the blood varies
according to age, sex and physiological conditions of the
body. In normal healthy adults, they range from 6,000 to
10,000 leukocytes per micro litre blood (Junqueira et al.,
2005). Majorities of these white blood cells migrate to the
tissue, where they perform multiple functions as tissue
macrophage and mostly died by apoptosis.
Blood platelets (thrombocytes) are nonnucleated disk
like cell fragments 2 to 4 µm in diameter. Platelets
originate from the fragmentation of giant polypoid
megakaryocytes that reside in the bone marrow. Platelets
count range from 200,000 to 400,000 per micro litre of
blood. Platelets have a life span of about 10 days.
Platelets function; the role of platelets in controlling
haemorrhage can be summarized as primary aggrega-
tion, secondary aggregation, blood coagulation, clot
retraction and clot removal (Junqueira et al., 2005). The
study was designed to see the effect of Eucalyptus
globules on the haematological parameters using wistar
rats.
MATERIALS AND METHODS
Animals
Twenty five adult Wistar rats weighing between 80 to 130 g were
used for the study. The rats were purchased from the animal house
of Faculty of Pharmacy, Obafemi Awolowo University Ile-Ife,
Nigeria. They were bred for weeks in the animal house of
Department of Anatomy, University of Ilorin. The rats were fed with
pellets grower mash obtained from Bendel feed mill, Yoruba road,
Ilorin and water ad libitum during the breeding period designed to
acclimatize the rats. They were exposed to 12 h of light and
darkness per day. The animals were care for in accordance with the
recommendations provided in the “Guide f or the Care and Use of
Laboratory Animals” prepared by the National Academy of
Sciences (NIH, 1985).
The rats were randomly grouped into five groups. A: control
group, and groups 1 to 4 were the experimental groups. Each of the
rats were marked at the tail with different colours of pen marker and
put into different segments of the cage, according to their group.
The rats were sacrificed after four weeks of extract administration
Oyesomi et al. 47
using cervical dislocation. Blood from each rat was collected into
labelled heparinised bottle to prevent coagulation of the blood and
analyzed for the haematological parameters.
Preparation of extract
Fresh leaves of the plant E. globulus were collected around the
Department of Anatomy, University of Ilorin, Nigeria. Botanical
identification of the plants was done at the herbarium of the
Department of Botany, Faculty of Sciences, University of Ilorin. The
fresh leaves were dried under laboratory condition as this helps
prevent destruction of active constituents of the plant, which may
occur on exposure to radiation, and drying lasted for a week.
The plant extract was prepared by the process of hydro
distillation using the Clevenger apparatus in which the grinded plant
material was heated. The evaporated oil were condensed and
decanted into sample bottles and refrigerated.
Administration of extract
Administration of the aqueous extract was done orally by means of
calibrated syringe with attached rubber cannula. The control group
received normal saline and DMSO4. The experimental groups of 1,
2, 3, and 4 received extract of E. globulus at doses of 12.5, 25.0,
50.0, and 72.5 mg/ml respectively. The assigned doses per groups
were administered daily and lasted for duration of four weeks.
Haematological parameters analysis
Evaluation of the haematological parameters was carried out using
automated haematological analyzed K-X-21 made by Symex, Kobe,
Japan. Sample of blood from the Wistar rats in heparinized bottle
were analyzed using this machine for accuracy. Each sample was
run twice and the average value calculated and recorded. The co-
efficient of error of the analyzer machine is less than 5%. Data
obtained were presented as mean ± standard deviation and in
some cases; the use t-test was employed for comparism and the
level of significance was predetermined as p ≤ 0.05.
RESULTS
There was steady increase in the haemoglobin concen-
tration and the estimated total red blood cell counts
across the concentration gradient with increasing
concentrations of the oil extract. The control group have a
mean haemoglobin concentration of 9.63 ± 0.3 mg/dl and
12.1 ± 0.2 mg/dl for the group 4 with high dose of the oil
extract. The estimated total red blood cell counts for the
control group was 4.45 ± 0.04 (×106) and 6.16 ± 0.15 (×
106) for the group 4. There was statistical significant
difference between them (Table 1).
The mean haemoglobin concentration for the control
group was 21.5 ± 0.5 pg and for the group 1 was 14.5 ±
0.5 pg which statistically significant. These values
increases with the increase in the concentration of the oil
extract from group 2 to group 4. Similar pattern were
observed for the mean corpuscular haemoglobin
concentration (Table 2).
The estimated total white blood count for the control
group was 5.55 ± 0.5 × 109/L and that for the group 4 was

48 Afr. J. Biochem. Res.
Table 1. Haemoglobin concentration (mg/dl) and total estimated Red Blood Cells counts (x106) in adult wistar rats.
Experimental group
Haemoglobin concentration
(mg/dl)
Red blood cell counts
(x106)
Control
9.63 ± 0.3
4.45 ± 0.04
Group 1
9.70 ± 0.2
4.52 ± 0.01
Group 2
9.90 ± 0.6
4.79 ± 0.01
Group 3
10.30 ± 0.25
4.87 ± 0.02
Group 4
12.10 ± 0.2*
6.16 ± 0.15*
(*) indicates statistical significant at p ≤ 0.05. Data were expressed as mean ± standard deviation.
Table 2. Mean Corpuscular Volume, Mean Corpuscular Haemoglobin , and Mean Corpuscular Haemoglobin Concentration in adult wistar
rats.
Experimental
group
Mean corpuscular volume
(MCV)
Mean corpuscular haemoglobin
(MCH)
Mean corpuscular haemoglobin
concentration (MCHC)
Control
53.5 ± 0.5
21.5 ± 0.5
39.01 ± 1.00
Group 1
57.5 ± 0.5
14.5 ± 0.5*
24.00 ± 0.01*
Group 2
60.5 ± 0.5
16.0 ± 0.1
28.50 ± 0.01
Group 3
62.5 ± 0.5
16.5 ± 0.5
34.00 ± 0.02
Group 4
63.0 ±1.0*
17.5 ± 0.5
36.50 ± 0.50
(*) indicates statistical significant at p ≤ 0.05. Data were expressed as mean ± standard deviation.
Table 3. White blood cells count (x109/l), estimated Neutrophil counts (%), and estimated total Lymphocyte counts (%) in adult wistar rats.
Experimental group
White blood cells count
(x109/l)
Neutrophil counts
(%)
Lymphocyte counts
(%)
Control
5.55 ± 0.50
10.0 ± 0.10
81.5 ± 0.5
Group 1
5.65 ± 0.05
10.0 ± 0.10
84.5 ± 0.1
Group 2
6.70 ± 0.10
10.0 ± 0.10
88.0 ± 1.0
Group 3
7.20 ± 0.10*
12.0 ± 0.10
90.0 ± 0.1
Group 4
8.30 ± 0.10*
15.0 ± 0.10*
91.5 ± 05*
(*) indicates statistical significant at p ≤ 0.05. Data were expressed as mean ± standard deviation.
8.3 ± 0.3 × 109/L. The neutrophil counts was stable in the
control, group 1 and 2 but steadily increases from group
3 to group 4 and this was significant. Similar observations
were not recorded in the lymphocytes counts which show
a linear increase along the concentration gradients of the
administered oil extract (Table 3).
DISCUSSION
The study demonstrated the effect of varied concen-
tration of oil extract of E. globulus on the haematological
parameters in adult Wistar rats. The apparent increase in
the haemoglobin concentrations across the experimental
groups was dose dependent and this may be due to
increased iron concentration present in the extract. This
finding was corroborated by Osawa and Namiki (2005)
that observed increased iron concentrations of various
extract of E. globulus. Though, the haemoglobin value
was 9.6 mg/dl on the average for the control group, the
steady rise in the values with increase in concentrations
of the extract across the experimental groups may also
be due to the presence of some of the phytochemical
contents of eucalyptus globulus that may have increased
the size of the red blood cells. This observation was
corroborated Yakubu et al., 2008; Oyesomi and Ajao,
2011 where the roles of phytochemical agents in
reproductive hormones and testis were demonstrated
respectively.
The reduction of the mean corpuscular volume (MCV)
and that of the mean corpuscular haemoglobin
concentration (MCHC) by the oil extract of Eucalyptus
globulus across the increased concentration gradient
administered to wistar rats may be due to the decrease in
size of the red blood cells produced which may partly
explained the findings of the increase in the estimated

total red blood cell counts that was recorded from the
study. Though, some of the constituents of the extract
may stimulate production of blood cells; these may be
immature and may be of irregular shapes and sizes. The
mechanisms by which this carried out is not fully
understood and beyond the scope of the present study.
However, this observation was corroborated by Osawa
and Namiki (2005) and Medubi et al. (2010) in their
various related studies.
The present study demonstrated a gradual increase in
the estimated total white blood cell count (WBC) from that
of those of the control groups and these appears to dose
dependent. This may be result from the immune busting
activities of some this medicinal plants as demonstrated
by Adefolaju et al. (2009) where aqueous extract of plant
have Hepatoprotective activity in rats. However, the
selective busting of the lymphocytes component of the
differential counts was not clearly understood and that
post a future challenge for research. In conclusion, the
study shows that the essential oil extract of E. globulus
administered at increasing dosage used as outlined in the
present study for the duration of one month enhanced the
haemopoietic activities in wistar rats. The mechanisms
for the observed increased may be due to the presence
of some constituents of iron which are of great
importance in the production of blood.
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