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International Journal of
PHARMACEUTICAL
AND BIOMEDICAL
RESEARCH
Research article
Evaluation of the hypoglycemic effect of aqueous extract of Phyllanthus
amarus in alloxan-induced diabetic albino rats
Herbert O.C. Mbagwu1, Clement Jackson1*, Idongesit Jackson2, Godwin Ekpe2, Udeme Eyaekop1,
Grace Essien1
1Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Uyo, Akwa Ibom State, Nigeria
2Department of Clinical Pharmacy and Biopharmacy, Faculty of Pharmacy, University of Uyo, Nigeria
Received: 05 Nov 2010 / Revised: 15 Nov 2010 / Accepted: 29 Nov 2010 / Online publication: 13 Aug 2011
ABSTRACT
The hypoglycemic potential of aqueous extract of Phyllanthus amarus Schum was investigated in alloxan-induced
diabetic albino rats. The extract at a dose of 260 mg/kg produced a significant (P< 0.05) reduction in blood glucose level by
112% at 24 h of oral administration. At 390 mg/kg, significant reduction (P< 0.05) in blood glucose levels of 102% (6 h) and
82% (24 h) were observed. A significant reduction (P<0.01) in blood glucose level of 81% and 61% (day 7) at doses of 130
and 260 mg/kg of extract respectively were observed. The extract also a highly significant (P<0.001) decrease in blood
glucose level of 38% and 30% (day 14) at doses of 130 and 260 mg/kg respectively. On the administration of 390 mg/kg dose
of extract, significant reduction (P<0.001) in blood glucose level of 41% on day 7 and 16% on day 14 were observed. The
above results indicate the presence of hypoglycemic constituents in the plant, Phyllanthus amarus Schum.
Key words: Hypoglycemic, Aqueous extract, Phyllanthus amarus Schum, Alloxan- induced diabetes
1. INTRODUCTION
Plants are well known in traditional herbal medicine for
their hypoglycemic activities, and available literature indicate
that there are more than 800 plant species showing
hypoglycemic activity [1]. The World Health Organization
has recommended the evaluation of the effectiveness of
plants in conditions where safe orthodox drugs are scarce [2].
Studies have shown that phytochemicals isolated from plant
sources have been used for the prevention and treatment of
cancer, heart disease, diabetes mellitus, and high blood
pressure [3]. Drug management of diabetes mellitus without
associated untoward effects has also remained a challenge for
orthodox medical practice. This has necessitated exploration
and screening of medicinal plants with acclaimed therapeutic
efficacies in diabetes mellitus management as recommended
by the World Health Organization Expert committee on
Diabetes Mellitus [4]. As plant metabolism is based on
carbohydrates, much research has explored the sugar
lowering potential of plants. Many plants have been reviewed
but satisfactory clinical studies are needed.
Phyllanthus amarus is a monoecious, occasionally
dioecious, upright or ascending herb, which grows up to
60cm high, or occasionally higher. The bracts and stipules
are linear-lanceolate, 1 mm long, cream with a brownish
middle rib. The stem is round, greenish or reddish, glabrous
and woody at the base [5]. The present research was aimed to
investigate antidiabetic activities of leaf extract of
Phyllanthus amarus in alloxan induced diabetic rats.
2. MATERIALS AND METHODS
2.1 Plant material
The whole plant of phyllanthus amarus were collected in
October 2009 from a cultivated farmland at Aka-offot in Uyo
Local Government Area of Akwa Ibom State, Nigeria. Dr
(Mrs.) M. E. Bassey, a taxonomist of the Department of
Botany and Ecological Studies, University of
Uyo,Nigeria,did the plant identification and authentication.
The specimen voucher (UUH 1461) was deposited in the
Herbarium of the Department of Botany and Ecological
Studies of the University of Uyo.
ISSN
N
o: 0976-0350
Available online at
www.pharmscidirect.com
Int J Pharm Biomed Res 2011, 2(3), 158-160
*Corresponding Author. Tel: 2348035499427, Fax:
Email: clementjackson1@yahoo.com
©2011 PharmSciDirect Publications. All rights reserved.
Herbert O.C. Mbagwu1 et al., Int J Pharm Biomed Res 2011, 2(3), 158-160
159
2.2 Extraction procedure
The leaves were dried in shade at room temperature. The
dried leaves were powdered by using grinder to coarse
powder, packed into Soxhlet column and then extracted with
70 % ethanol for 24 h. The excess of solvent was removed
using rotatory flash evaporator. The obtained crude extract
was stored in airtight container in refrigerator below 10°C for
further studies.
2.3 Experimental animals
Healthy Wistar albino rats of (150-200 g) were used
throughout the experiments. The animals were procured from
the Animal House of Nigeria Institute of Trypanosomiasis
Research (NITR), Vom, Jos, Nigeria. Before initiation of
experiment, the rats were acclimatized for a period of 7 days.
Standard environmental conditions such as temperature
(26-±2ºC), relative humidity (45-55%) and 12 h dark/light
cycles were maintained in the quarantine. All the animals
were fed with rodent pellet diet (Guinea® feeds, Ewu, Edo
State) and water was allowed ad-libitum under strict hygienic
conditions. Ethical clearance for performing the experiments
on animals was obtained from Institutional Animal Ethics
Committee (IAEC).
2.4 Drugs and chemicals
Alloxan monohydrate was purchased from Sigma-Aldrich,
Switzerland. Glibenclamide (Glanil) was procured from
Nigerian- German Chemicals Plc, Lagos. All the other
chemicals used were of analytical grade.
2.5 Acute toxicity studies
LD50 was assumed using 50% death within 72 h
following i.p. administration of the extract at different doses
(500, 1000, 1500, 2000, 2500 and 3000 mg/kg). Healthy
Wistar albino rats weighing 150-200 g (10 per group) were
used in this experiment. The number of animals, which died
during this interval, was expressed as percentage mortality
(Table 1).
Table 1
Acute toxicity studies
D
ose of extract (mg/kg)
M
ortality rate
P
ercentage mortality
500
0
0
1000
0
0
1500
2
6
6.7
2
000
3
100
2
500
3
100
3
000
3
100
2.6 Induction of diabetes
Alloxan (2, 4, 5, 6-tetraoxypyrimidine; 2, 4, 5, 6-
pyrimidinetetrone) is an oxygenated pyrimidine derivative [6]
and was originally isolated in 1818 by Brugnatelli and got its
name in 1838 by Friedrich Wöhler and Justus von Liebig [7].
Alloxan is a toxic glucose analogue, which selectively
destroys insulin-producing cells in the pancreas when
administered to rodents and many other animal species. This
causes an insulin-dependent diabetes mellitus (called
"Alloxan Diabetes") in these animals, with characteristics
similar to Type 1 diabetes in humans [6]. Alloxan
monohydrate was used to induce diabetes.
2.7 Anti-diabetic activity
Fasting blood glucose was determined after depriving the
rats of food for 16 h with free access of drinking water.
Hyperglycemia was induced by a single i.p. injection of 150
mg/Kg of alloxan monohydrate (Sigma-Aldrich, Switzerland)
in sterile saline. After 5 days of alloxan injection, the
hyperglycemic rats (glucose level > 250 mg/dL) were
separated and divided into different groups comprising of 6
rats each for the anti-diabetic study. The treatment (p.o.) was
started from the same day except normal control and diabetic
control groups for a period of 14 days. During this period,
animals in all groups had free access to standard diet and
water. Blood glucose levels were estimated on 1st, 7th and 14th
day of the treatment. On the 14th day, blood samples were
collected from overnight fasted rats by cardiac puncture
under mild ether anesthesia for biochemical estimations.
3. RESULTS AND DISCUSSION
The present investigation highlights the antidiabetic
efficacy of aqueous extract of Phyllanthus amarus. In alloxan
induced diabetic rats treated with the plant extract, dose
dependent reduction in blood glucose level was observed
(Table 2).
Alloxan, a urea derivation and beta cytotocin causes
massive destruction of β-cells of the islets of langerhans
resulting in reduced synthesis and release of insulin. This
leads to hyperglycemia and diabetes [8].
It is well established that sulphonylureas produce
hypoglycemia by increasing the secretion of insulin from
pancreas and these compounds are active in mild alloxan
diabetes (nearly all β-cells have been destroyed) [9]. From
the results, Glibenclamide did not produce reduction in blood
glucose levels. Hence, the state of diabetes was severe.
Phytochemical analysis of the extract in this study showed
the presence saponins, flavonoids lignans alkaloid and
cardiac glycosides. Studies on other plants have identified
similar compound like flavonoid [10.11], terpenoids and
tannins [12], steroids [13], lignans [14] and alkaloids [15] to
be responsible for hypoglycemic activity. The observed
hypoglycemic effects of Phyllanthus amarus extract,
therefore, could have resulted from the combined activity of
these compounds present in it. Regarding the mode action of
the extract, the exact mechanism cannot be deduced from this
experiment. It may be due to enhanced peripheral utilization
of glucose.
Herbert O.C. Mbagwu1 et al., Int J Pharm Biomed Res 2011, 2(3), 158-160
160
Table 2
Effects of aqueous extract on the fasting blood glucose levels (mg/dL) in alloxan-induced diabetic rats
T
reatment
D
ose
B
lood glucose level (mg/dL)
0
h 1 h
6
h
2
4 h
D
ay 7
D
ay 14
E
xtract 130 mg/Kg
2
73.8±40.90
3
39.7±60.10
(
124%)
4
02.8±47.80
(
147%)
4
16.8±58.00
(
152%)
2
22.8±29.30
(
81%)
104.2±13.20**
(
38%)
2
60 mg/Kg
4
13.0±83.90 526.7±57.30
(
128%)
519.5±43.10
(
126%)
4
64.0±34.50*
(
112%)
2
51.2±24.70**
(
61%)
123.3±17.20***
(
30%)
3
90 mg/Kg 530.3±46.80 569.2±30.80
(
107%)
539.5±43.20*
(
102%)
4
35.2±36.90*
(
82%)
2
18.8±32.10***
(
41%)
84.30±12.30***
(
16%)
G
libenclamide
6
.75 mg/Kg
3
62.3±60.90
4
67.5±59.50
(
129%)
4
85.5±44.50
(
134%)
4
77.5±46.20
(
132%)
3
95.5±82.20
(
109%)
4
95.70±68.90
(
137%)
C
ontrol
2
0 mL/Kg
2
53.5±60.50
2
76.0±48.80
(
109%)
2
74.2±64.30
(
108%)
2
63.7±80.30
(
104%)
529.5±27.90
(
209%)
533.3±36.70
(
210%)
Data are expressed as Mean ± Standard Error of Mean (SEM); n=6
* Significant values at P<0.05 compared to the control
** Significant values at P<0.01 compared to the control
*** Significant values at P<0.001 compared to the control
Values in parenthesis represent percentage change in blood glucose at time t compared with at time zero
However, the possibility of enhanced insulin release
from surviving β-cells, pancreatic β-cells regeneration or the
insulinomimetic of some of the components present in the
Phyllanthus amarus extract or a combination of these effects
cannot be ruled out. Furthermore, results of a previous study
showed that aqueous extract of Phyllanthus amarus lowers
plasma glucose in normoglycemic mice, in a dose related
pattern [17]. It was suggested that the mechanism of action
may be due to increase in circulating insulin level
(hyperinsulinemia) or by enhancing tissue utilization of
glucose. In the oral glucose tolerance test on normoglycemic
albino rats, Phyllanthus amarus extract showed significant
reduction of serum glucose. It was observed that the
hypoglycemic mechanism involved insulin-like effect, most
probably through the peripheral glucose consumption [16].
The present study also indicates that Phyllanthus amarus
can partially inhibit alloxan renal toxicity as observed from
serum levels. The literature reports reveal that flavonoids and
tannins present in the plant extract known to possess
antidiabetic activity. In the present investigation, the
observed antidiabetic potential of test extract may be due to
presence of similar phytochemical which was evident by
preliminary screening.
4. CONCLUSIONS
From this study, we can state that the Ethanolic extract
of Phyllanthus amarus has beneficial effects on blood
glucose levels as well as improving hyperlipidemia and other
metabolic aberrations. Further pharmacological and
biochemical investigations will clearly elucidate the
mechanism of action and will be helpful in projecting this
plant as a therapeutic target in diabetes research.
REFERENCES
[1] Rajagopal, K., Sasikala, K., Singapore Med J 2008, 49, 137-141.
[2] World Health Organisation. Second Report of the WHO Expert
Committee on Diabetes Mellitus. Technical Report Series 1980, 646,
66.
[3] Waltner-Law, M.E., Wang, X.L., Law, B.K., J Biol Chem 2002, 277,
34933-34940.
[4] Adeneye, A.A., Olagunju, J.A. Biology and Medicine, 2009, 1, 1-10.
[5] LaGow, B., Livingstone, G., Hanson, U., PDR for Herbal Medicines,
3rd Ed. New Jersey, Thompson PDR 2004, pp. 92-93.
[6] Lenzen, S., Diabetologica 2008, 51, 216-226.
[7] Lenzen, S., Panten, U., Deabetologica 1998, 31, 337-342.
[8] Szuldelski, T., Physiology Research 2001, 50, 536-546.
[9] Nammi S., Boini, M.K., Lodagala, S.D., Behara, R.B., Biomed Central
2003, 3, 1-9.
[10] Schimizu, M., Phytochemistry 1984, 23, 1885-1888.
[11] Adeneye, A.A., Agbaje, E.O., African Journal of Biomedical Research
2008, 11, 65-71.
[12] Reher, G., Slijepcevic, M., Krans, L., Planta Medicine 1991, 57, A57-
A58
[13] Ivorra, M.D., Paya, M., Villar, A., Journal of Ethnopharmacology 1989,
27, 243-275.
[14] Karawya, M.S., Wahab, S.A., Journal of Natural Products 1984, 47,
775-780.
[15] Xu, Z., Wang, X., Zhou, M., Ma, L., Deng, Y., Zhang, H., et al.
Phytotherapy Research 2008, 22, 97-101.
[16] James, D.B, Onolabi, O.A., Hassan. S., Odemene, L., African Journal of
Biotechnology 2009, 818, 1637-1642.
[17] Adeneye, A.A., Amole, O.O., Adeneye, A.K., Fitoterapia 2006, 77,
511-514.