Antioxidant Property and Cardiovascular Effects of Coconut (Cocos nucifera) Water

Abstract

Coconut water, a natural nutritious beverage that contains several biologically active chemical substances, is used in the management/treatment of several disorders in Eastern Nigeria. This study was set up to evaluate the antioxidant potential of coconut water and its effect on the cardiovascular system in albino rats. Twenty five adult male albino rats, used in this work, were placed into five groups (A, B, C, D and E), of five rats per group. Groups A, B, C and D were administered orally with 0.5, 1.0, 1.5 and 2.0 ml/kg body weight respectively of the coconut water for fourteen consecutive days. Group E was the control. Glutathione peroxidase (GPX), superoxide dismutase (SOD) and Malondialdehyde (MDA) levels were used to investigate antioxidant activity of the coconut water, while lipid profile was determined as an index of its cardiovascular effect. GPX and SOD activity was significantly higher (P < 0.05) in the test groups than in untreated group, while MDA levels decreased significantly (P< 0.05) in the treated groups relative to the control. There was Original Research Article Agbafor et al; IJBcRR, 5(4): 259-263, 2015; Article no.IJBcRR.2015.030 260 a significant reduction (P< 0.05) in total cholesterol, triglycerides and low density lipoprotein, while high density lipoproteins increased significantly (P< 0.05) in the test animals relative to the control. These observations were found to be linearly dose-dependent. These results may be due to the chemical constituents of the coconut water, and could be partly responsible for its application in the management of some disorders.

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*Corresponding author: Email: kagbafor@yahoo.co.uk;
International Journal of Biochemistry Research
& Review
5(4): 259-263, 2015, Article no.IJBcRR.2015.030
ISSN: 2231-086X
SCIENCEDOMAIN international
www.sciencedomain.org
Antioxidant Property and Cardiovascular Effects of
Coconut (Cocos nucifera) Water
K. N. Agbafor
1*
, S. O. ELOM
2
, M. E. Ogbanshi
1
, A. O. OKO
1
, A. J. Uraku
1
,
V. U. O. Nwankwo
1
, B. A. Ale
3
and K. I. OBIUDU
3
1
Department of Biochemistry, Ebonyi State University, P.M.B. 053 Abakaliki, Ebonyi State, Nigeria.
2
Department of Medical Biochemistry, Ebonyi State University, P.M.B. 053 Abakaliki, Ebonyi State,
Nigeria.
3
Department of Chemical Sciences, Godfrey Okoye University, Enugu, Nigeria.
Authors’ contributions
This work was carried out in collaboration between all authors. All authors read and approved the final
manuscript.
Article Information
DOI: 10.9734/IJBcRR/2015/9805
Editor(s):
(1)
Tomio Yabe, Department of Applied Life Scinece, Gifu University, Japan.
Reviewers:
(1)
Anonymous, Jmo State University Owerri, Nigeria.
(2)
Anonymous, National Hospital of Sri Lanka, Sri Lanka.
(3)
Anonymous, University of South Africa, South Africa.
(4)
Anonymous, Palestine Polytechnic University, Palestine.
Complete Peer review History:
http://www.sciencedomain.org/review-history.php?iid=845&id=3&aid=7424
Received 1
st
March 2014
Accepted 5
th
July 2014
Published 19
th
December 2014
ABSTRACT
Coconut water, a natural nutritious beverage that contains several biologically active chemical
substances, is used in the management/treatment of several disorders in Eastern Nigeria. This
study was set up to evaluate the antioxidant potential of coconut water and its effect on the
cardiovascular system in albino rats. Twenty five adult male albino rats, used in this work, were
placed into five groups (A, B, C, D and E), of five rats per group. Groups A, B, C and D were
administered orally with 0.5, 1.0, 1.5 and 2.0 ml/kg body weight respectively of the coconut water for
fourteen consecutive days. Group E was the control. Glutathione peroxidase (GPX), superoxide
dismutase (SOD) and Malondialdehyde (MDA) levels were used to investigate antioxidant activity of
the coconut water, while lipid profile was determined as an index of its cardiovascular effect. GPX
and SOD activity was significantly higher (P < 0.05) in the test groups than in untreated group, while
MDA levels decreased significantly (P< 0.05) in the treated groups relative to the control. There was
Original Research Article

Agbafor et al; IJBcRR, 5(4): 259-263, 2015; Article no.IJBcRR.2015.030
260
a significant reduction (P< 0.05) in total cholesterol, triglycerides and low density lipoprotein, while
high density lipoproteins increased significantly (P< 0.05) in the test animals relative to the control.
These observations were found to be linearly dose-dependent. These results may be due to the
chemical constituents of the coconut water, and could be partly responsible for its application in the
management of some disorders.
Keywords: Antioxidant enzymes; total cholesterol; lipoproteins; serum; albino rats.
1. INTRODUCTION
The coconut palm (Cocos nucifera), found
throughout the tropics and subtropics, is one of
the most widely distributed edible fruit- bearing
palms in the world. It is a large palm, growing up
to 30 meter (98ft) tall, with pinnate leaves 4-6
meters (13-20) long and pinnae 60-90cm long.
Coconuts are generally classified in to two type:
tall and dwarf [1]. Coconut water is a natural
liquid that contains many biologically active
compounds. These include numerous antioxidant
compounds that have the ability to scavenge free
radicals in the body. It also contains cytokins, a
plant chemical which has shown anti-aging and
anti-carcinogenic effects. Coconut water also
contains B vitamins, which are water soluble and
are required for cellular functions [2]. Coconut
water contains a variety of inorganic ions such as
calcium, magnesium, phosphorus, sodium,
potassium and selenium [3]. Further, other
components found in coconut water include
sugars, sugar alcohols, lipids, amino acids,
nitrogenous compounds, organic acids and some
enzymes. They play different functional roles in
plant and human systems due their distinct
chemical properties [4].
Many studies have shown that the antiviral,
antibacterial, anti-inflammatory and antioxidant
activities of coconut water may help ease a
number of minor to severe health conditions.
This nutrient rich drink has been used to regulate
blood pressure, blood sugar, and cholesterol
levels, and it has been found to boost energy
levels and increase metabolism in human body.
Other conditions that it has been found to be
effective in treating include stomach flu,
dysentery, indigestion, constipation, intestinal
worms, urethra stones, malfunctioning kidneys,
dry and itchy skins, age spot and wrinkles [5].
Similarly, some recent studies have found that
coconut water can help increase high density
lipoprotein (good) cholesterol, which makes it a
wonderful natural treatment for maintaining good
cardiovascular health. Young coconut water has
estrogen-like characteristics. It mixes easily with
blood, and was used during World war II in
emergency transfusions [6].
Coconut water can also serve as emergency
short-term intravenous hydration fluid. This is
possible because it contains a high level of sugar
and other salts that make it possible to be used
in the bloodstream, much like the modern lactate
Ringer Solution or a dextrose/water solution as
an intravenous solution [7]. In Eastern Nigeria,
coconut water is used for several medicinal
purposes which include management and
treatment of various disorders such as
gastrointestinal disorders, high blood pressure,
dehydration, kidney malfunction, anxiety, etc.
Glutathione peroxidase (GPX) is an enzyme
which acts on lipid hydroperoxide (LHP)
substrates that are released from membrane
phospholipids by phospholipaseA
2
. It can utilize
cholesterol hydroperoxide and hydrolyzes
hydrogen peroxide (H
2
O
2
) at low concentration
[8]. The antioxidant enzyme, GPX, catalyze the
reaction of H
2
O
2
and hydroperoxides formed
from fatty acid, thereby effectively removing toxic
peroxides from living cells. It plays the important
role of protecting cells from potential damage by
free radicals, formed by peroxide decomposition
[9].
Lipid peroxidation is an established mechanism
of cellular injury, and is used as an indicator of
oxidative stress. Polyunsaturated fatty acids
peroxides generate malondialdehyde (MDA) and
4-hydroxyalkanals upon decomposition [10].
Superoxide dismutase (SOD) decomposes
superoxide anion into hydrogen peroxide and
oxygen at very high rates. Superoxide radical is
involved in diverse physiological and patho-
physiological processes [11]. Lipid profile is a
general term that is given to tests for high density
lipoprotein, low density lipoprotein, total
cholesterol and triglycerides. A shift in the normal
level of any of these components of lipid profile is
of interest to cases of cardiovascular disorders
[12].

Agbafor et al; IJBcRR, 5(4): 259-263, 2015; Article no.IJBcRR.2015.030
261
Documented scientific evidence on the various
medicinal applications of coconut water has been
scarce in this part of the world. Hence, the
present study investigated the antioxidant
property of coconut water and its possible effect
on the functionality of the cardiovascular system.
2. MATERIALS AND METHODS
The chemicals used in this research were of
analytical grade.
2.1 Preparation of Coconut Water
Coconuts fruits were plucked from a tall matured
coconut tree at Amuda in Ezza North Local
government area of Ebonyi State. They were
identified by Prof. S. C. Onyekwelu of Applied
Biology Department, Ebonyi State University,
Abakaliki, Nigeria. Each coconut seed was
punctured at the holes using a sterilized nail. It
was then placed over a container and allowed
the water to drain. The coconut water was
obtained fresh and used immediately.
2.2 Animals and Handling
Ethical approval was given by Ebonyi State
University Research and Ethics Committee.
Twenty-five adult male albino rats, weighing 140-
155g were bought from the animal house of
Biochemistry Department, University of Nigeria,
Nsukka. They were placed in five groups (A-E) of
five rats in each group, and kept in animal house
of Biochemistry Department, Ebonyi State
University Abakaliki for seven days to
acclimatize. All the rats were allowed free access
to feed (rat chaw) and water before and
throughout the experiment. Groups A, B, C and
D were treated orally with 0.5, 1.0, 1.5 and 2.0
ml/kg body weight respectively of the coconut
water for fourteen consecutive days. Group E
was the control. Blood samples were collected
from the animals following an overnight fast
through cardiac puncture under mild anaesthesia
using diethylether.
2.3 Measurement of Antioxidant Property
The method of Ohkawa et al. [13] was used to
measure the level of MDA. SOD and GPX
activities were determined by the methods of
Kakkar and Viswanathan [14] and Tappel [15]
respectively.
2.4 Assessment of Cardiovascular Effect
The enzymatic method of determination of
cholesterol concentration described by Burtis et
al. [12] was adopted for measurement of total
cholesterol, while the methods described by
ochei and kalhalkar [16] were used to determine
the levels of HDL and triglycerides. LDL
concentration was calculated from Friedewald
equation as stated by Burtis et al. [12].
2.5 Data Analysis
Statistical analysis was done using analysis of
variance (ANOVA). Means were compared for
significance using Duncan’s multiple range test
(P<0.05) [17].
3. RESULTS AND DISCUSSION
There was a noticeable increase in physical
activities and rate of food and water intake in the
groups given the coconut water compared with
the control (data not shown). We are currently
investigating the possible mechanisms of these
observations. Chemical constituents reported in
coconut water have been shown to influence
these processes. For example, recent studies
have shown coconut water is equally as effective
carbohydrate-electrolytes sports drink in
replenishing fluids after exhaustive exercise and
it is also superior to water and sports drink
options [7]. Inorganic ions are required for normal
cellular functions, and are critical for enzyme
activation, bone formation, hemoglobin function,
gene expression, and the metabolism of amino
acids, lipids and carbohydrates [18]. The
recorded significant increase (p<0.05) in the
activity of glutathione peroxidase and superoxide
dismutase in the test groups relative to the
untreated group (Table 1) may be attributed to
the antioxidant constituents of the coconut water.
Coconut water contains a wealth of
micronutrients such as inorganic ions and
vitamins that enhance the natural antioxidant
system of the body. These micronutrients acts
directly in the body to quench free radicals that
can damage cells or they can indirectly increase
the production of antioxidant enzymes (such as
superoxide dismutase, catalase and glutathione
peroxidase) that promote the removal of
damaging radicals [7].
The levels of lipid peroxidation marker,
malondialdehyde (MDA) in the treated groups
were significantly lower (p<0.05) than those in
the control group. This may be due to the

Agbafor et al; IJBcRR, 5(4): 259-263, 2015; Article no.IJBcRR.2015.030
262
Table 1. Levels of (GPX), (MDA) and SOD in the albino rats after fourteen days of treatment
Group
GPX Activity (U/l)
SOD, activity (U/mg protein)
MDA conc. (nmol/ml)
A 324.80±2.10
d
8.05±0.70
e
5.75±0.33
c
B 383.86±2.74
d
15.30±1.15
d
4.47±0.41
c
C 408.81±3.52
c
27.62±1.42
c
3.81±0.15
d
D 495.27±3.14
b
36.09±2.29
b
2.21±0.11
b
E 180.43±3.34
a
4.20±0.21
a
9.11±0.81
a
All values are Mean ± Standard deviation; n=5 Values in the same column having different superscripts are
significantly different (P < 0.05).
Table 2. Concentrations of total cholesterol, triglycerides, high density lipoprotein and low
density lipoprotein of the animals after fourteen days of treatment
Animal
group
Total cholesterol
(
/
dl)
Triacylglycerol
(
/
dl)
HDL
(
/
dl)
LDL
(
/
dl)
A 224.87+1.41
d
128.38+2.2
b
20.80
±
3.1
a
178.39+2.14
b
B 193.87+3.02
d
121.51
±
1.7
b
24.70
±
2.1
a
174.87
±
1.35
b
C 121.81
±1.
90
c
116.69
±
4.0
b
32.24
±
2.2
b
124.83
±
1.29
c
D 81.60
±
2.44
b
91.38
±
6.2
c
38.36
±
2.4
b
50.11
±
2.15
d
E 263.32
±
2.10
a
174.87
±
3.06
a
18.46
±
2.1
a
189.88
±
5.9
a
Values are mean ± standard deviation, n=5. Values in same column with different superscripts differ significantly
(P<0.05)
corresponding increase in the activity of
glutathione peroxidase and other antioxidant
body systems. This result is consistent with the
reports of Evans and Halliwel [19]; Shenken [20],
that hyper-metabolism gives rise to an increased
production of reactive oxygen species (ROS) or
free radicals as a result of increased oxidative
damage to the various components of human
cell, especially the polyunsaturated fatty acids in
the nucleus. Fortunately, living organisms have
well developed antioxidant systems to neutralize
the most detrimental effects of these oxidizing
free radicals by donating electrons or indirectly
as a part of metalloenzymes (a diverse class of
enzymes that require a catalytic metal ion for
their biological activity) such as glutathione
peroxidase (selenium-present in coconut water)
or superoxide dismutase (zinc, copper) to
catalyse the removal of oxidizing species [20].
There was a significant reduction (p<0.05) in
total cholesterol, triglycerides and LDL, and
significant increase (p<0.05) in HDL in the
treated groups relative to the control (Table 2
above). This confers cardiovascular protective
property to the coconut water. The chief role of
these lipid compounds (except HDL) in
pathological processes is as factors in the
genesis of atherosclerosis of vital arteries,
causing cerebrovascular, coronary and
peripheral vascular disease [21]. Epidemiological
studies have shown that high levels of HDL have
protective value against cardiovascular diseases
such as ischemic stroke and myocardial
infarction [22]. The exact biochemical
mechanism involved in the reduction of total
cholesterol, triglycerides and LDL, and increase
in HDL by the coconut water is presently not well
understood. According to Agbafor and Akubugwo
[23], the hypocholesterolaemic effect of ethanolic
extract of Cymbopogon citratus may be ascribed
to modification of cholesterol uptake from the
intestine, conversion of cholesterol to bile acids
and increased excretion of bile acids. Anurage
and Rajamohan [6] showed that coconut water
has cardioprotective effect in experimental
myocardial infarction induced in rats and this was
probably attributed to the rich of mineral ions in
coconut water, especially potassium.
5. CONCLUSION
Based on the results of this research,
consumption of coconut water may boost body’s
antioxidant systems, which neutralize the effects
of free radicals, and reduce the risk of
cardiovascular disorders. These results,
therefore, not only make coconut water popular
to consume as refreshing beverage but also
valuable in health and medicine. We are
presently investigating the possible biochemical
mechanisms responsible for our major findings.
COMPETING INTERESTS
Authors have declared that no competing
interests exist.

Agbafor et al; IJBcRR, 5(4): 259-263, 2015; Article no.IJBcRR.2015.030
263
REFERENCES
1. Pradeep Kumar T. Management of
Horticultural Crops. Horticulture Science
Series. 2008;11:539-587.
2. Depient F, Bruce WR, Shangari N, Mehta
R, O’Brien PJ. Mitochondrial function and
toxicity: Role of B-vitamin on the one-
Carbon transfer pathways. Chemical and
Biological Interaction. 2006;163:113-132.
3. Charles P. The effect of coconut water on
hydration and disease molecules.
2012;60(8):160-281.
4. Kathleen M, Zelman LD. The truth about
coconut water. Journal of Molecular
Chemisty. 2011;3(1):72-85.
5. Young J, Ge L. The chemical composition
and biological property of Coconut water.
Molecules. 2009;14:51-44.
6. Anurage P, Rajamohan T. Cardio
protective effect of tender coconut water in
experimental myocardial infaction. Plant
Foods and Human Nutrition. 2003;58:1-12.
7. Kalman D, Feldman S. Comparison of
coconut water and a carbohydrate
electrolyte sport drink on measure of
hydration and physical performance in
exercise-trained man. Journal of the
International society of sport Nutrition.
2012;9(1):76-85.
8. Finn JK, Tregenza T, Normal MD.
Defensive tool used in coconut-carrying
Octopus. Current biology.
2009;19(23):1069-1070.
9. Khan MA, Tania M, Zhang D, Chen H.
Antioxidant enzymes and Cancer. China
Journal of Cancer Research.
2010;22(2):87-92.
10. Esterbauer H, Schaur RJ, Zollner, H.
Chemistry and Biochemistry of 4-
hydroxyalkanals, malondialdehyde and
related aldehydes. Free Rad. Biol. Med.
1991;11:81-128.
11. Johnson F, Giulivi C. Superoxide
dismutases and their impact on human
health. Mol. Aspects Med.
2005;26(4):340-352.
12. Burtis CA, Ashwood ER, Bruns OE.
Fundamentals of clinical chemistry 6
th
edition, Elsevier, Haryana. 2008;539-555.
13. Ohkawa H, Ohishi N, Yagi K. Assay for
lipid peroxide in animal tissues by
thiobarbituric acid reaction. Annal
Biochem. 1979;95:51-55.
14. Kakkar P, Das B, Viswanathan PN.
Modified spectrophotometric assay of
SOD. Indian J. Biochem. Biophys.
1984;2:130-132.
15. Tappel L. Glutathione Peroxidase and
Hydroperoxides. Methods Enzymol.
1978;52:506-513.
16. Ochei J, Kolhatkar AE. Laboratory science
6
th
edition Mc Gram Hill, New Delhi.
2007;190-198.
17. Sokal RR, Rholf FJ. Practice of statistic in
research. Freeman Press, San Francisco.
1969;21-26.
18. Wall MM. Ascorbic acid and mineral
composition of longan (Dimocarpus
longan), Lychee (Litchi chinensis) and
Ranbutan (Nephelium leppacum) cultivars
grown in Hawaii. Journal of Food
Compostion. 2006;19:655-663.
19. Evans P, Halliwell B. Micronutrients.
Oxidant/antioxidant status. British Journal
of Nutrition. 2001;85:67-74.
20. Shenken, A. The key role of
Micronutrients. Clinical Nutrition.
2006;25:1-13.
21. Murry RK, Granner DK, Mayes PA,
Rodwell, V. W. Harpers Illustrated
Biochemistry, 26
th
ed. McGraw – Hill, India;
2003.
22. Philip B. HDL – C, very low levels of LDL –
C and cardiovascular events. N. Eng. J.
Med. 2007;233(3):208–214.
23. Agbafor KN, Akubugwo EI.
Hypocholesterolemic effect of ethanol
extract of fresh leaves of Cymbopogon
citratus. Afr. J. Biotech. 2007;6:596–598.
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