International Journal of Pharma and Bio Sciences

RESEARCH ARTICLE PHARMACOLOGY

ARTICALTICLE

ANTIDIABETIC ACTIVITY OF METHANOLIC EXTRACT OF HIBISCUS

CANNABINUS IN STREPTOZOTOCIN INDUCED DIABETIC RATS

Corresponding Author

T.SUNDARRAJAN
Santhiram college of pharmacy, nandyal, Kurnool district, andhra
pradesh, india

Co Authors

T.RAJ KUMAR1, E.UDHAYAKUMAR1, M.SEKAR1 AND M.K.SENTHIL

KUMAR2.
1
Santhiram college of pharmacy, Nandyal, Kurnool district, andhra pradesh, india.
2
j.k.k.Nataraja college of pharmacy, komarapalayam, Namakkal district, tamil nadu,
India.

ABSTRACT
The aim of present study was to evaluate antidiabetic activity of methanolic extract of
Hibiscus cannabinus; family Malvaceae leaves in streptozotocin induced diabetic rats. The
alcoholic extract of Hibiscus cannabinus was studied for antidiabetic activity in streptozotocin
induced diabetic rats by oral administration of extract 400mg/kg body weight for 15 days. The
effect was compared with oral dose of 0.5mg/kg Glibenclamide. The determination of blood
glucose level by GOD-POD kit method. The result shows the alcoholic extract of Hibiscus
cannabinus leaves significantly lowered the blood glucose of hyperglycemic rats. From the
toxicity study it was observed that methanolic extract of Hibiscus cannabinus was nontoxic up
to 5g/kg body weight and phytochemical study showed the presence of phytosterols,
flavonoids and glycosides. It is concluded that Hibiscus cannabinus leaf extract has significant
antidiabetic activity, which lowered the fasting blood glucose level in Streptozotocin induced
diabetic rats.

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KEY WORDS
Anti diabetic activity, Hibiscus cannabinus, streptozotocin, GOD-POD.

INTRODUCTION

Diabetes mellitus is a serious complex Hibiscus cannabinus (Malvaceae) is an

chronic condition that is a major source of ill annual or perennial herbaceous bush and has
health worldwide. This metabolic disorder is several forms with varying colors of flowers. It
characterized by hyperglycemia and is native to China and grown widely as an
disturbances of carbohydrate, protein, and fat ornamental plant throughout India. The flowers
metabolisms, secondary to an absolute or are considered emollient, and an infusion of
relative lack of the hormone insulin. Besides the petals is used as a demulcent. Its decotion
hyperglycemia, several other factors including is given in bronchial catarrh in India. Previous
dislipidemia or hyperlipidemia are involved in studies show that the plant possesses anti-
the development of micro and macrovascular complimentary, antidiarrhetic and
complications of diabetes that are the major antiphologistic activities5. The leaves and
causes of morbidity and death1.According to flowers have been found to be effective in the
WHO projections, the prevalence of diabetes is treatment of heart disorders. No reports are
likely to increase by 35%. Currently, there are available on the antidiabetic activity of Hibiscus
over 150 million diabetic patients worldwide and cannabinus leaves. Hence, the present study
this is likely to increase to 300 million or more by focuses on the scientific investigation of
the year 2025. Statistical projection about India antidiabetic activity of Hibiscus cannabinus
suggests that the number of diabetics will rise leaves6, 7.
from 15 million in 1995 to 57 million in the year
2025, the highest number of diabetics in the MATERIALS AND METHODS
world2. Reasons for this rise include increase in
sedentary lifestyle, consumption of energy-rich (i) Plant material
diet, obesity, higher life span, etc. Other regions Fresh leaves were collected from tropical
with greatest number of diabetics are Asia and area in Yercaud and authentified by G.V.S
Africa, where diabetes mellitus rates could rise Moorthy, Joint director, Botanical survey of
to twofold to threefold than the present rates3. India; Coimbatore was submitted to
Evaluation of plant products to treat diabetes department of pharmacology for further
mellitus is of growing interest as they contain reference.
many bioactive substances with therapeutic
potential. In recent years, several authors (ii) Extraction
evaluated and identified the antidiabetic The leaves, shade dried, Powdered in a
potential of traditionally used Indian medicinal grinder mixture to obtain coarse powder and
plants using experimental animals. Previous then passed through 60 mesh sieve. The
studies confirmed the efficacy of several powdered leaves were extracted using
medicinal plants in diabetes mellitus. Although a continuous hot extraction method by
large number of medicinal plants have been gradient extraction technique. The extracts
already tested for their antidiabetic effects, were evaporated to dryness and
these effects remain to be investigated in phytochemical screenings were performed8
several other Indian medicinal plants4.
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(iii) Animals 200mg/dl were considered as diabetic rats
Swiss albino mice of female sex weighing and used for the experimentation10. Diabetic
20-25gms were employed for toxicity study. animals were grouped five days after
Albino wistar rats of male sex weighing 200- induction of diabetes Effect of Methanolic
250 gms were employed for antidiabetic Extract of Hibiscus cannabinus in
study. They were housed in standard streptozotocin induced diabetes in rats.
environment condition and fed with standard
rodent diet with water and ad libitum. Ethical EXPERIMENTAL DESIGN
clearance for the animal study was obtained
from Institutional Animal Ethical Committee In the experiment rats were divided into
(09MP03AUG2009) of CPCSEA the following groups with six animals each
(887/ac/CPCSEA). Group I : Normal control received 1% w/v
gum acacia 1ml/kg for 15 days orally.
(iv) Toxicity Study Group II : Diabetic control received 1% w/v
An acute oral toxicity study was performed gum acacia 1ml/kg for 15 days orally.
as per OECD guidelines 423. By Acute toxic Group III : Diabetic rats received methanolic
class method Swiss albino mice of female extract of Hibiscus cannabinus leaf 400mg/kg
sex weighing 20-25gms were used for the body weight once a day orally for 15 days.
study. Acute toxic class method is a stepwise Group IV : Diabetic rats treated with
procedure with use of three animals of a Glibenclamide 0.5mg/kg orally once a day for
single sex per step. Depending on mortality 15 days.
or morbidity status of the animals. Average
2-4 steps may be necessary to allow Rats were fasted overnight and the
judgement on the acute toxicity of the blood was withdrawn from the orbital sinus of
substance. Three animals were used for the eye on the 5th day, 15th day and 20th day
each step. The animal were placed post induction to determine blood glucose by
individually and observed for any sign of GOD-POD kit method. The change body
toxicity, morbidity or mortality during the first weight was observed throughout treatment
24hrs, with special given attention during the period in experimental animals.
first 4 hours and daily thereafter for a total of
14 days.9 STASTISTICAL ANALYSIS
All values were expressed as Mean ±
(v) Induction of diabetes S.D. The differences between control and
All the rats were fasted overnight before the treatment groups were tested for significance
administration of Streptozotocin. Diabetes using ANOVA followed by Dunnet’s t test.
was induced in rats by intra peritoneal P<0.05 were considered significant.
injection of streptozotocin dissolved in 0.1M
sodium citrate buffer pH4.5 at the dose of
RESULTS
50mg/kg body weight. After the injection they
had free access to food and water. The
animals were allowed to drink 5% glucose The preliminary phytochemical studies
solution overnight to overcome indicate the presence of phytosterols,
hypoglycaemic shock. The development of Flavonoids and glycosides in methanolic
diabetes was confirmed after 48hrs of extract Hibiscus cannabinus leaf. In acute
Streptozotocin injection. The animals having toxicity study the methanolic extract of Hibiscus
fasting blood glucose level more than
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cannabinus did not produce lethality up to the dose level of 2000mg/kg.

Table- 1
Effect of Hibiscus cannabinus leaf extract on body weight in Streptozotocin induced diabetic
rates

Body weight in gms(Mean±SEM)

Groups Post induction days
th
5 day 15th day 20th day
Control 167.2±3.25 173±3.54 181±3.34
Diabetic control 163.8±3.34 136.8/±2.10* 125.3±2.39*
Diabetic rats+ Control 164.3±1.98 170.3±1.764* 175.8±1.47*
Diabetic rats+ glibenclamide 165.1±2.77 170.8±82.62* 178.5±2.37
Values are expressed as Mean ± S.E. n=6.
P*<0.05 Experimental groups were compared with diabetic control.
P*<0.05 Diabetic groups were compared with control group.

In the antidiabetic activity, the effects of weight compared to normal rats. Oral
Hibiscus cannabinus leaf extract on body weight administration of leaf extract at the dose of
is measured on 5th, 15th and 20th day of post 400mg/kg showed a significant) increase
induction and were compared with normal and (P<0.05) in body weight on 15th and 20th day of
diabetic control groups. The values are shown in post induction when compared to untreated
Table No-1. Streptozotocin induced diabetic rats diabetic rats.
showed a significant decrease (P<0.05) in body

Table- 2
Effect of Hibiscus cannabinus leaf extract on blood sugar level in streptozotocin induced
diabetic rats.
Blood glucose level in mg/dl (Mean±SEM)
Groups Post induction days
th
5 day 15th day 20th day
Control 62.2±1.22 61.05±1.11 60.47±1.16
Diabetic control 273.46±14.7 260.2±1.34* 269.8±11.88*
Diabetic rats+ Control 273.10±17.04 135.4±13.99* 70.61±2.24*
Diabetic rats+
263.20±3.59 127.06±8.07* 69.06±1.28*
glibenclamide
Values are expressed as Mean ± S.E. n=6.
P*<0.05 Experimental groups were compared with diabetic control.
P*<0.05 Diabetic groups were compared with control.

The effect Hibiscus cannabinus leaf No-2. Streptozotocin induced rats showed a
extract on fasting blood glucose level is significant increase (P<0.05) in fasting blood
measured on 5th, 15th and 20th day of post glucose level compared to normal rats. Oral
induction and compared with normal and diabetic administration of leaf extract at the dose of
control groups. The values are shown in table 400mg/kg body weight showed a significant

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decrease (P<0.05) in blood glucose level in 10 II diabetes mellitus. The standard drug
and 15 days of treatment. The fasting blood Glibenclamide stimulates insulin secretion from
glucose level on 15th day of post induction (10 beta cells of islets of langerhans. From the
days of treatment) was 135.4±13.99 mg/dl study, it is suggested that the possible
compared to fasting blood glucose of diabetic mechanism by which the plant extract
control animal 260.2±1.34mg/dl. The group decreases the blood glucose level may be by
treated with Glibenclamide 0.5 mg/kg showed potentiation of insulin effect either by increase
fasting blood glucose level of 127.06±8.07 mg/dl. in pancreatic secretion of insulin from beta
On 20th day of post induction ( 15days of cells of islets of langerhans or by increase in
treatment ), the leaf extract treated group showed peripheral glucose uptake.
a fasting blood glucose level of 70.61 ± 2.24
mg/dl, compared to untreated diabetic animal CONCLUSION
which showed a fasting blood glucose level of
269.8 ± 11.88 mg/dl. The group treated with The methanolic extract of Hibiscus
Glibenclamide 0.5 mg/kg orally showed fasting cannabinus leaf exhibited significant
blood glucose level of 69.06± 1.28 mg/dl. hypoglycemic activity in streptozotocin induced
diabetic rats. From the phytochemical analysis
DISCUSSION it was found that the major chemical
constituents of the leaf extract were flavonoids
In the present study the hypoglycemic and glycosides. On the basis of above
activity of methanolic extract of Hibiscus evidence it is possible that the presence of
cannabinus leaves was evaluated in flavonoids may be responsible for the observed
Streptozotocin induced diabetic rats. The antidiabetic activity. Further pharmacological
continuous treatment of leaf extract for a period and biochemical investigations are underway
of 15 days produced a significant decrease in to find out the active constituents responsible
blood glucose level in diabetic rats which is for antidiabetic activity and to elucidate its
comparable to that of standard drug mechanism of action.
Glibenclamide which is used in treatment of type

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