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Asian Journal of Pharmacology and Toxicology 01 (01); 2013; 17-25
17
Received on: 07-09-2013
Accepted on: 10-09-2013
Published on: 15-09-2013
Satish S
Research Scholar, Shri Jagdish Prasad
Jhabarmal Tibrewala University,
Rajasthan
Email: satish.mpharm@gmail.com
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Investigation on Essential oil of Cymbopogon citratus
in Treatment of Alzheimer’s disease
Satish S
Research Scholar, Shri Jagdish Prasad Jhabarmal Tibrewala University, Rajasthan
ABSTRACT
Nootropic acitivity of essential oil of Cymbopogon Citratus (EOCC) was
studied in mice. Morries water maze employed to evaluate learning and
memory parameters. Scopolamine (0.4 mg/kg, i.p.) was used to induce
amnesia in mice. The essential oil (1gm/kg) significantly attenuated
amnestic deficits induced by scopolamine (0.4 mg/kg, i.p.) and natural
aging, also exhibited decreased escape latencies time (ELT) and
increased Time Spend in Target Quadrant (TSTQ) significantly in the
aged mice and scopolamine induced amnesic mice as compared with
Piracetam (200 mg/kg, i.p.). To delineate the possible mechanism
through which Cymbopogon Citratus elicits the anti-amnesic effects, we
studied its influence on central cholinergic activity by estimating the
whole brain acetylcholinesterase activity. Cymbopogon Citratus
significantly decreased acetyl cholinesterase activity in mice. The
results indicate that essential oil of Cymbopogon Citratus might prove to
be a useful memory restorative agent in the treatment of dementia seen
in elderly. The underlying mechanism of action can be attributed to its
anti acetylcholinesterase property.
Keywords: Nootropic activity, Cymbopogon Citratus, Memory, anti
acetylcholinesterase
Cite this article as:
Satish S. Investigation on Essential oil of Cymbopogon citratus in Treatment of
Alzheimer’s disease
Asian Journal of Pharmacology and Toxicology 01 (01); 2013; 17-25
Asian Journal of Pharmacology and Toxicology 01 (01); 2013; 17-25
18
1. INTRODUCTION
Age, stress, emotions are conditions that may lead to
anxiety, high BP and dementia or to more ominous
threats like schizophrenia and Alzheimer’s disease
(AD)[1]. Nootropic agents such as piracetam,
pramiracetam, aniracetam and choline esterase
inhibitors like Donepezil are presently used for
improving memory, mood and behavior. Allopathic
psychoactive drugs have been the main stay of treating
mental illness in India and worldwide. Some nootropic
agents (Piracetam) are widely used but the resulting
chemophobia associated with them and other similar
agents has made their use limited [2]. During last few
years there has been increase in usage of alternative
medicines by the patients for such ailments, many
herbal medicines have been accepted in our country for
treating anxiety disorders and cognitive dysfunctions.
Cymbopogon citratus, commonly known as lemongrass,
is a tropical perennial herb belonging to the family
Poaceae (true grasses), commonly used in traditional
Indian, Chinese, and Brazilian medicines. Cymbopogon
citratus has been shown to be effective in the treatment
of fever and infection, headaches, stomach aches, and
rheumatic pain, also reported as sedative,
antispasmodic, analgesic, anti-inflammatory and
antihypertensive agents[3-4].
2. MATERIALS AND METHODS
Plant Materials: Cymbopogon Citratus were collected
from local areas of Udupi Karnataka and were
identified by Dr. Kempegowda HOD Botany
Department of Bangalore University Karnataka.
Voucher specimens (KCP/BG-11) of the collected
samples were deposited in the Departmental
laboratory.
Isolation of the essential oil:
Plant material was subjected to hydrodistillation for 3
h using a Clevenger type apparatus. The oil was dried
over anhydrous Na2SO4 and preserved in a sealed vial
at 4 0C until further analysis All the doses were
prepared in distilled water using 5% Tween 80
solution as suspending agent and administered orally.
In all cases, the concentrations were prepared in 1
ml/100g of body weight. The test substances were
administered in a single dose using a gastric intubation
tube after fasting for 3 to 4 h.
Drugs and Chemicals: Scopolamine Hydrobromide IP
(Cadila health care Ltd Goa), Piracetam (Normabrain®
Torent Pharmaceuticals LTD, vill, India), DTNB (5,5-
dithiobis-2- nitro benzoic acid), Acetylcholine iodide,
Sodium dihydrogen phosphate, Dipotasium hydrogen
phosphate (Hi-Media, India). Scopolamine hydro
bromide was dissolved separately in normal saline and
injected i.p., volume of i.p. injection was 1 ml/100 g of
mouse.
Acute Toxicity Studies: Cymbopogon Citratus at
different doses (50-2000 mg/kg) was administered
orally to mice with the help of a specially designed oral
needle connected to a polythene tube. ECCO was
administered at the same time on each day. During the
first four hours after the drug administration, the
animals were observed for gross behavioral changes if
any, for 7 days. Parameters such as hyperactivity,
grooming, convulsions, sedation served. The dose
1gm/kg/day was selected.
Animals: Swiss mice of either sex weighing around 18
g (younger ones, aged 8 weeks) and 25 g (older ones,
aged 28 weeks) were used in the present study.
Animals were procured from disease free. They were
acclimatized to the laboratory conditions for 5 days
before behavioral studies. The animals had free access
to food and water and were maintained under 12:12 h
light and dark cycles. Institutional Animals Ethics
Committee (IAEC) had approved the experimental
design and care was taken as per guidelines of CPCSEA,
Dept. Govt. of India.
BEHAVIORAL MODELS[5-8]:
MORRIS WATER MAZE (MWM):
It represents a more specific test of spatial memory.
The technique of using escape from water to motivate
learning has been used traditionally. The simplicity and
versatility of the tank makes it the most widely
acceptable experimental model for the assessment of
cognitive skills in the animals. The essential feature of
the technique is that mice are placed in to a large
circular pool of water and can escape onto a hidden
platform (opaque water). Thus the platform offers no
local cues to guide the escape behavior. The mice can
escape from swimming by climbing onto the platform
and over time the mice apparently learns the spatial
location of the platform from any starting position at
the circumference of the pool. The only spatial cues are
those outside of the water tank and are primarily visual
cues.
Construction: The apparatus used is a circular water
tank (100 cm in diameter) filled to a depth of 30 cm
with water (25oC). Four points equally distributed
along the perimeter of the tank served as starting
locations. The tank was divided arbitrarily into four
equal quadrants and a small platform (5 cm width) was
located in the center of one of the quadrants. The
platform remained in the same position during the
training days.
Asian Journal of Pharmacology and Toxicology 01 (01); 2013; 17-25
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PROCEDURE:
The mice were released into the water and allowed 90
s to find the platform. Animals received 4 trials per day
with 5 min inter-trial interval for 8 days until the
performance was stable and the latency to find the
platform was low (<10 sec). The test formulations were
administered 30 min prior to the first trial daily. Time
to find the hidden platform is considered as escape
latency (EL). The platform in the water maze was kept
at the same position throughout the test to assess the
effect of EOCC on spatial reference memory.
GROUPING OF ANIMALS:
Group I: Control (normal saline was administered
orally for 8 days. ELT (Escape latency Time) and TSTQ
(Time (in second) Spend in Target Quadrant) was
noted after 45 min of administration on the 8th day,
again on the 12th day i.e. on 4th day.)
Group II: Scopolamine (0.4 mg/kg, i.p.) Was injected
intraperitonially and ELT (Escape latency Time) and
TSTQ (Time (in second) Spend in Target Quadrant) was
noted after 45 min of administration on the 8th day,
again on the 12th day i.e. on 4th day.
Group III: Piracetam (200 mg/kg, p.o.) + Scopolamine
(0.4 mg/kg, i.p.): Piracetam was administered orally for
8 days. ELT ( Escape latency Time ) and TSTQ (Time (in
second) Spend in Target Quadrant ) was noted after 45
min of administration on the 8th day, after 45 min
injected Scopolamine intraperitonially for 1 days. ELT (
Escape latency Time ) and TSTQ ( Time (in second)
Spend in Target Quadrant ) was noted after 45 min of
administration on the 8th day, again on the 12th day i.e.
on 4th day.
Group IV: EOCC (1gm/kg) + Scopolamine (0.4 mg/kg,
i.p.): EOCC(1gm/kg) was administered orally for 8
days. ELT (Escape latency Time) and TSTQ (Time (in
second) Spend in Target Quadrant) was noted after 45
min of administration on the 8th day, after 45 min
injected Scopolamine intraperitonially for 1 days. ELT
(Escape latency Time) and TSTQ (Time (in second)
Spend in Target Quadrant) was noted after 45 min of
administration on the 8th day, again on the 12th day i.e.
on 4th day.
Group V: Only EOCC (1gm/kg) was administered orally
for 8 days. ELT (Escape latency Time) and TSTQ (Time
(in second) Spend in Target Quadrant) was noted after
45 min of administration on the 8th day, again on the
12th day i.e. on 4th day.
Group VI: Only Piracetam (200 mg/kg, p.o.) was
administered orally for 8 days. ELT ( Escape latency
Time ) and TSTQ ( Time (in second) Spent in Target
Quadrant ) was noted after 45 min of administration on
the 8th day, again on the 12th day i.e. on 4th day.
Aged groups:
Group I: Control (normal saline was administered
orally for 8 days. ELT (Escape latency Time) and TSTQ
(Time (in second) Spend in Target Quadrant) was
noted after 45 min of administration on the 8th day,
again on the 12th day i.e. on 4th day.
Group II: Piracetam (200 mg/kg, p.o.) was
administered orally for 8 days. ELT (Escape latency
Time) and TSTQ (Time (in second) Spend in Target
Quadrant) was noted after 45 min of administration on
the 8th day, again on the 12th day i.e. on 4th day.
Group III: EOCC (1gm/kg) was administered orally for
8 days. ELT (Escape latency Time) and TSTQ (Time (in
second) Spent in Target Quadrant) was noted after 45
min of administration on the 8th day, again on the 12th
day i.e. on 4th day.
Estimation of Brain Acetyl Cholinesterase (AChE)
Activity9,10 :
On the 9th day the animals were killed by cervical
dislocation carefully to avoid any injuries to the tissue.
Mice brains were isolated quickly and placed in ice-
cold saline. The tissues were weighed and
homogenized in 0.1 M Phosphate buffer (pH 8). 0.4ml
aliquot of the homogenate was added to a cuvette
containing 2.6 ml Phosphate buffer (0.1M, ph 8) and
100µl of DTNB. The contents of the cuvette were mixed
thoroughly by bubbling air and absorbance was
measured at 412 nm in a UV spectrophotometer. When
absorbance reaches a stable value, it was recorded as
the basal reading. 20µl of substrate i.e acetylthiocholine
was added and change in absorbance is recorded for a
period of 10 min at interval of 2 min. Change in the
absorbance per minute is thus determined. Acetyl
cholinesterase (AChE) activity was determined on 9th
day, and calculated using following formula.
R = 5.74× 10-4 × A/ CO
Where,
R = Rate in moles of substrate hydrolyzed / minute /
gm tissue
A = Change in absorbance / min
CO = Original concentration of the tissue (mg / ml).
Statistical Analysis
All the results were expressed as mean ± Standard
error. The data was analyzed using one-way ANOVA
followed by multiple range tests was used for the
analysis of non-normally distributed data. p <0.05 was
considered as significant.
3. RESULTS:
Acute Toxicity Study: No mortality was observed
following oral administration of EOCC even with the
highest dose (2000 mg/kg). However HS at doses more
than 2000 mg/kg produced profuse watery stools in
Asian Journal of Pharmacology and Toxicology 01 (01); 2013; 17-25
20
animals. Both the doses of EOCC had no toxic effect on
the normal behavior of the rats.
Effect of Essential oil of Cymbopogon Citratus on
ELT in young mice (Day1):
The young animals treated with Essential oil of
Cymbopogon Citratus (1 gm /kg, p.o.) showed
significant(p<0.01) reduction in ELT of both learning
and memory task as compared to normal control of
young mice. EOCP+ Scopalamine group showed
significant (p<0.001) reduction in ELT of both learning
and memory task as compared to scopolamine induced
group. Piracetam+ Scopalamine group also showed
significant similar effect. Piracetam (200 mg/kg, i.p.)
signinficantly (p<0.001) improved ELT in learning and
memory, as compared with normal control group of
young mice. (Table & graph:1)
n=6 in each group. Data expressed as mean ± S.E.M.. statistical analysis were performed using one-way ANOVA followed by Dunnett’s test. *P <
0.05, **P < 0.01, ***P < 0.001 vs. control
Table No.1. Effect of EOCC on Escape Latency in Morries Water Maze : ( Young)
Young Mice - Day I – EOCC :
Control
Scopolamine
Piracetam
Piracetam + Scopolamine
EOCC+ Scopolamine
EOCC
0
20
40
60
80
100 ***
*** *** *** ***
Treatment
ELT (sec)
Graph No.1. Effect of EOCC on Escape Latency in Morries Water Maze : ( Young)
(B) Effect of Essential oil of Cymbopogon Citratus on ELT in young mice (Day4):
The young animals treated with Essential oil of
Cymbopogon Citratus (1gm/kg, p.o.) showed significant
(p<0.01) reduction in ELT of both learning and
memory task as compared to normal control of young
mice. EOCC+Scopalamine group showed significant
(p<0.001) reduction in ELT of both learning and
memory task as compared to scopolamine induced
group. Piracetam+Scopalamine group showed
significant (p<0.001) reduction in ELT of both learning
and memory task as compared to scopolamine induced
group. Piracetam (200 mg/kg, p.o.) signinficantly
(p<0.001) improved ELT in learning and memory, as
compared with normal control group of young mice.
(Table & graph: 2)
Group
No.
Treatment
Dose
ELT (sec)
mean ± S.E.M [n=6]
Day IV
I
Control
10 ml/kg
46.17 ± 0.4014
II
Scopolamine
0.4 mg/kg
80.83 ± 0.3073***
III
Piracetam
200 mg/kg
31.00 ± 0.3651***
IV
Piracetam + Scopolamine
200 mg/kg + 0.4 mg/kg
41.17 ± 0.3073***
V
EOCC + Scopolamine
1 gm/kg + 0.4 mg/kg
43.50 ± 0.2236***
VI
EOCC
1 gm/kg
39.50 ± 0.4282***
n=6 in each group. Data expressed as mean ± S.E.M.. Statistical analysis were performed using one-way ANOVA followed by Dunnett’s test. *P <
0.05, **P < 0.01, ***P < 0.001 vs. control
Table No.2. Effect of EOCC on Escape Latency in Morries Water Maze on day 4: (Young)
Group No.
Treatment
Dose
ELT (sec)
mean ± S.E.M [n=6]
Day I
I
Control
10 ml/kg
77.00 ± 0.3651
II
Scopolamine
0.4 mg/kg
94.83 ± 0.3073***
III
Piracetamp
200 mg/kg
52.17 ± 0.3073***
IV
Piracetam + Scopolamine
200 mg/kg + 0.4 mg/kg
63.83 ± 0.4773***
V
EOCC + Scopolamine
1 gm/kg + 0.4 mg/kg
67.83 ± 0.3073***
VI
EOCC
1 gm/kg
61.83 ± 0.3073***
Asian Journal of Pharmacology and Toxicology 01 (01); 2013; 17-25
21
Young Mice – Day IV - EOCC :
Control
Scopolamine
Piracetam
Piracetam + Scopolamine
EOCC + Scopolamine
EOCC
0
20
40
60
80
100 ***
*** *** *** ***
Treatment
ELT (sec)
Graph No.2. Effect of EOCC on Escape Latency in Morries Water Maze: (Young)
(C) Effect of Essential oil of Cymbopogon Citratus on TSTQ in young mice:
The young animals treated with Essential oil of
Cymbopogon Citratus (1gm/kg, p.o.) showed
significant(p<0.01) improvement in TSTQ values of
both learning and memory task as compared to normal
control group of young mice. EOCC+Scopolamine group
showed significant (p<0.001) improvement in TSTQ
value of both learning and memory task as compared to
scopolamine induced group.
Piracetam+Scopolamine group showed significant
(p<0.001) improvement in TSTQ value of both learning
and memory task as compared to scopolamine induced
group. Piracetam (200 mg/kg, i.p.) signinficantly
(p<0.001) increased in TSTQ values in learning and
memory, as compared with control group of young
mice. (Table & graph: 3)
Group No.
Treatment
Dose
TSTQ (sec)
mean ± S.E.M [n=6]
I
Control
10 ml/kg
58.33 ± 0.3333
II
Scopolamine
0.4 mg/kg
34.67 ± 0.4216***
III
Piracetam
200 mg/kg
78.83 ± 0.3073***
IV
Piracetam + Scopolamine
200 mg/kg + 0.4 mg/kg
70.83 ± 0.4014***
V
EOCC + Scopolamine
1 gm/kg + 0.4 mg/kg
71.17 ± 0.3073***
VI
EOCC
1 gm/kg
69.33 ± 0.3333***
n=6 in each group. Data expressed as mean ± S.E.M.. statistical analysis were performed using one-way ANOVA followed by Dunnett’s test. *P <
0.05, **P < 0.01, ***P < 0.001 vs. control
Table No.3. Effect of EOCC on TSTQ in Morries Water Maze : ( Young)
Control
Scopolamine
Piracetam
Piracetam + Scopolamine
EOCC + Scopolamine
EOCC
0
20
40
60
80
100
***
*** *** *** ***
Treatment
TSTQ (sec)
Graph No.3. Effect of EOCC on TSTQ in Morries Water Maze : ( Young)
(D) Effect of Essential oil of Cymbopogon Citratus on ELT in aged mice (Day1):
The aged animals treated with Essential oil of
Cymbopogon Citratus (1gm/kg, p.o.) showed significant
(p<0.01) reduction in ELT of both learning and
memory task as compared to control group of aged
Asian Journal of Pharmacology and Toxicology 01 (01); 2013; 17-25
22
mice. Piracetam (200 mg/kg, p.o.) signinficantly
(p<0.001) decreased ELT in learning and memory, as
compared with normal control group of aged mice.
(Table & graph:4 )
Group
No.
Treatment
Dose
ELT (sec) mean ± S.E.M [n=6]
Day I
I
Control
10 ml/kg
89.33 v 0.333
II
Piracetam
200 mg/kg
56.17 ± 0.4014***
III
EOCC
1 gm/kg
75.17 ± 0.3073***
n=6 in each group. Data expressed as mean ± S.E.M.. statistical analysis were performed using one-way ANOVA followed by Dunnett’s test. *P <
0.05, **P < 0.01, ***P < 0.001 vs. control
Table No.4. Effect of EOCC on Escape Latency in Morries Water Maze : ( Aged )
Aged Mice – Day I – EOCC :
Control
Piracetam
EOCC
0
20
40
60
80
100
***
***
Treatment
ELT (sec)
Graph No.4. Effect of EOCC on Escape Latency in Morries Water Maze : ( Aged )
(E) Effect of Essential oil of Cymbopogon Citratus on ELT in aged mice (Day4):
The aged animals treated with Essential oil of
Cymbopogon Citratus (1gm/kg, p.o.) showed
significant(p<0.01) reduction in ELT of both learning
and memory task as compared to control group of aged
mice. Piracetam (200 mg/kg, p.o.) signinficantly
(p<0.001) decreased ELT in learning and memory, as
compared with normal control group of aged mice.
(Table & graph:5)
Group
No.
Treatment
Dose
ELT (sec) mean ± S.E.M [n=6]
Day IV
I
Control
10 ml/kg
42.33 ± 0.3333
II
Piracetam
200 mg/kg
26.83 ± 0.3073***
III
EOCC
1 gm/kg
30.67 ± 0.3333***
n=6 in each group. Data expressed as mean ± S.E.M.. statistical analysis were performed using one-way ANOVA followed by Dunnett’s test. *P <
0.05, **P < 0.01, ***P < 0.001 vs. control
Table No.5. Effect of EOCC on Escape Latency in Morries Water Maze : ( Aged )
Aged Mice – Day IV – EOCC :
Control
Piracetam
EOCC
0
10
20
30
40
50
*** ***
Treatment
ELT (sec)
Graph No.5. Effect of EOCC on Escape Latency in Morries Water Maze : ( Aged )
(F) Effect of Essential oil of Cymbopogon Citratus on TSTQ in aged mice :
The aged animals treated with Essential oil of
Cymbopogon Citratus (1gm/kg, p.o.) showed
significant(p<0.01) improvement in TSTQ values of
both learning and memory task as compared to normal
Asian Journal of Pharmacology and Toxicology 01 (01); 2013; 17-25
23
control group of aged mice. Piracetam (200 mg/kg,
p.o.) signinficantly (p<0.001) increased in TSTQ values
in learning and memory, as compared with normal
control group of aged mice. (Table & graph: 6 )
Group No.
Treatment
Dose
TSTQ (sec) mean ± S.E.M [n=6]
I
Control
10 ml/kg
30.50 ± 0.2236
II
Piracetam
200 mg/kg
71.00 ± 0.3651***
III
EOCC
1 gm/kg
51.83 ± 0.3073***
n=6 in each group. Data expressed as mean ± S.E.M.. statistical analysis were performed using one-way ANOVA followed by Dunnett’s test. *P <
0.05, **P < 0.01, ***P < 0.001 vs. control
Table No.6. Effect of EOCC on TSTQ in Morries Water Maze : ( Aged )
Old Mice – EOCC :
Control
Piracetam
EOCC
0
20
40
60
80
***
***
Treatment
TSTQ (sec)
Graph No.6. Effect of EOCC on TSTQ in Morries Water Maze : ( Aged )
Effect on Acetylcholinesterase Activity:
The acetylcholiesterase activity of whole brain was
markedly elevated (p < 0.05) after scopolamine (0-4
mg/kg, p.o.) treatment. Piracetam (200 mg/kg, p.o.)
and EOCC (1gm/kg, p.o.) significantly lowered AChE
activity (Fig 7).
Group
Treatment
Dose
AChE (µM)
I
Normal control
10 ml/kg(p.o.)
0.12±0.0025
II
Scopolamine
0.4 mg/kg(i.p.)
0.18±0.0047***
III
Piracetam+Scopolamine
200 + 0.4(mg/kg)
0.12±0.0028###
IV
EOCC+Scopolamine
30 + 0.4(mg/kg)
0.14±0.0021 ###
V
EOCC
30 mg/kg (p.o.)
0.11±0.0022 a a a
VI
Piracetam
200 (p.o.)
0.09±0.0033***
Each group consists of 6 animals. Values are mean ±S.E.M. ***P < 0.001 compared to normal control group. aaaP< 0.001 compared to
scopolamine treated group. ###P < 0.001 compared to scopolamine treated group.
Table7: Effect of EOCC on whole brain acetyl cholinesterase activity on young mice using Elevated plus maze
Effect of EOCC on
Normal saline
scopolamine
piracetam + Scopolamine
EOCC + Scopolamine
EOCC
piracetam
0.00
0.05
0.10
0.15
0.20
0.25
***
aaa
ACh E (µ moles of Ach
hydrolysed/min/g
of protein)
graph:7 Effect of EOCC (1gm/kg, p.o.) On Whole brain acetyl cholinesterase activity of young mice .
Asian Journal of Pharmacology and Toxicology 01 (01); 2013; 17-25
24
Group
Treatment
Dose
AChE (µM)
I
Normal control
10 ml/kg
0.13±0.0033
II
Piracetam
200 mg/kg (p.o.)
0.07±0.0050***
III
EOCC
30 mg/kg (p.o.)
0.11±0.0021***
Each group consists of 6 animals. Values are mean ±S.E.M, (n=6). One way ANOVA followed by Dunnett’s test . ***indicates p< 0.001 as
compared to normal control group of aged mice. ** indicates p< 0.01 as compared to normal control group of aged mice. * indicates p< 0.05
as compared to normal control group of aged mice
Table8: Effect of EOCC on whole brain acetyl cholinesterase activity on aged mice using Elevated plus maze
Aged mice
Normal saline
Piracetam
EOCC
0.00
0.05
0.10
0.15 ***
***
ACh E (µ moles of Ach
hydrolysed/min/g
of protein)
Graph:8 Effect of EOCC (1gm/kg, p.o.) on Whole brain acetyl cholinesterase activity of aged mice
Values are mean ± SEM, AChE- whole brain AChE activity, a indicates p<0.05 Vs control, H = 16.67; df = 5; p < 0.05.
4. DISCUSSION
Aromatic plants had been used since ancient times for
their preservative and medicinal properties, and to
impart aroma and flavor to food. Hippocrates,
sometimes referred to as the ‘father of medicine’,
prescribed perfume fumigations. The pharmaceutical
properties of aromatic plants are partially attributed
to essential oils. The term ‘essential oil’ was used for
the first time in the 16th century by Paracelsus von
Hohenheim, who named the effective component of a
drug, ‘Quinta essential’[11]
Dementia of the Alzheimer type (DAT) is a common
disease with important consequences to the patient’s
life quality.2 Inhibition of the enzyme
acetylcholinesterase (AChE) is the basis of most drugs
used clinically for symptomatic relief of the early
stages of AD. Inhibition of AChE (i.e., reduction of the
enzyme responsible for breaking down ACh) results in
elevated levels of ACh in the brain, which is associated
with improvement of cognitive function including
memory12.
The ability of cholinesterase inhibitory activity in
cyclic monoterpenes was identified as the most active
compounds. These include Camphor, 1, 8-Cineole,
Beta-pinene, Alpha-pinene, together with their
inhibitory activities. It can be seen that, of the active
components, 1,8-cineole is likely to contribute most to
the activity of the oil since it is present in the greatest
concentration.[13-14].
The cholinesterase inhibitory properties of these 1,8-
cineole monoterpenes were only recently reported.
Antioxidant effects were noted with 1,8-cineole, alpha-
pinene and beta-pinene, but a pro-oxidant effect was
produced by camphor, a relatively major component of
the oil. It is likely that the pro-oxidant activity of
camphor is eclipsed by the antioxidant compounds so
that the total oil would have an overall antioxidant
effect[15].
EOCC also reversed the scopolamine-induced
impairment in learning and memory, when assessed
on MWM. Piracetam, the first representation of a class
of nootropic agents, has been shown to improve
memory deficits in geriatric individuals. Repeated
injections of piracetam had improved learning abilities
and memory capacities of laboratory animals[16-18].
Both piracetam and Cymopogon citratus meet major
criteria for nootropic activity, namely improvement of
memory in absence of cognitive deficit[19,20].
In the present study, Cymopogon citratus significantly
inhibited the AChE activity in the mice whole brain
homogenate, indicating its potential in the attenuation
of symptoms of cognitive deficits. Hence, the memory
improving activity of EOCC may be attributed to its
antioxidant, neuropro-tective, pro-cholinergic and
anti-acetylcholinesterase properties and can be of
enormous use in delaying the onset and reducing the
severity of Alzheimer’s disease. Further investigations
Asian Journal of Pharmacology and Toxicology 01 (01); 2013; 17-25
25
using more experimental paradigms are required for
further confirmation of nootropic potential of essential
oil of Cymopogon citratus in the treatment of various
cognitive disorders.
5. ACKNOWLEDGEMENTS
We would like to thank ICMR for the financial support
for this research (21/12/17/09/HSR, dated:
24/06/2010).
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