DIABETES AND ITS ASPECTS

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1. Introduction

Diabetes is a disorder of metabolism due to absolute deficiency or
diminished effectiveness of insulin. Due to lack of insulin, hyperglycemia and
glycosuria almost invariably occur (Hyder et al., 1998-99). It is a fatal health problem in the present world. Diabetes is the
fourth- leading cause of death (
Saha et al., 2006). The diabetic population is rapidly increasing globally, particularly in
the developing countries. South Asian region including, Bangladesh is the most
vulnerable focus. The estimated diabetes prevalence for 2010 worldwide is 285
million people corresponding to 6.4% of the world’s adult population. By 2030,
the number of people with diabetes is estimated to have risen to 438 million
(IDF, 2010).
The 10
countries estimated to have the highest numbers of people with diabetes in 2000
and 2030 are estimated. In 2000, Bangladesh is listed at 10 positions but for
2030, it will be raised at 7 positions reflecting anticipated changes in the
population size and structure in these countries between the two time periods
(Wild et al., 2004).

2. History of Diabetes mellitus

History
of Diabetes mellitus dates back to thousands of years. With discovery of
insulin in 1921 and glucose reducing drugs in 1955, treatment of diabetes was
certainly boosted up. But complications due to this disease still continue.  More importantly, in the third world
countries like Bangladesh the prevalence of diabetes is raising, partly because
of the insulin treatment, lack of knowledge, inadequate medical facilities and
insufficient health care.  The treatment
of diabetes is at present neither simple nor cheap. Insulin, the main
antidiabetic agent is extracted commercially from animal (cattle or pig) pancreas.
It is the principal agent to fight against the disease. Insulin is indicated
for ketosis prone juvenile-type diabetics as well as for those adult-onset
diabetics with insulinopenia who do not respond to diet therapy either alone or
in combination with oral hypoglycemic drugs. Ideal replacement therapy would
provide insulin in a manner comparable to the secretor pattern of normal
individuals. It is not possible to completely reproduce the physiologic
patterns of insulin secretion with subcutaneous injections of soluble or
longer-acting insulin suspensions or combinations of insulins. Even so, with
the help of appropriate modifications of diet and exercise, it has been
possible to achieve acceptable control of blood glucose by using variable
mixtures of short- and longer-acting insulin (Hyder et al., 1998-99). Thus, the investigation of proper alternatives of
insulin is very urgent and proper dietary adjunct is necessary for
diabetics. 

A significant proportion of these patients obviously fail to get proper
treatment and medication. Indigenous drugs, since long, have been used for the
treatment of diabetes (Said, 1969). Hundreds of plants are known to be useful in treating diabetes in
different corners of the world. 
Bangladesh is abundant in antihyperglycemic plants. These species may
represent a source of new hypoglycemic compounds for developing better remedies
to treat diabetic patients without serious side effects.

3. Diabetes: general consideration

Diabetic mellitus is a clinical syndrome characterized by
persistent hypoglycemia with or without glycosuria due to deficiency or
diminished effectiveness of insulin. The metabolic disarrangement is frequently
associated with permanent and irreversible functional and structural change in
the cells of the body and lead to many complications. The complications of
diabetes most characteristically affect the eye, the kidney and the nervous system
(Davidson, 1977).

4.1.
Primary Diabetes:

It consists of two main clinical types

i. Juvenile-onset or
insulin dependent diabetes and

ii. Maturity-onset or
insulin independent diabetes.

Although the precise etiology in still
uncertain, several contributing factors are known to be involved which differ
in younger and older-onset diabetes.

Both sexes suffer equally but in
lower age groups males and in middle age groups females are affected more.

In both types of diabetes a familial
tendency exists and twins are more often both diabetic when they are identical
than when they are non-identical.

Diabetes is seen to be associated
with other autoimmune diseases such as pernicious anemia, hyperthyroidism and
Addition’s disease.

Infection: There
is some evidence that viral infection may be involved in the etiology of
juvenile insulin-dependent diabetes.

Obesity: The
association of obesity and diabetes has long been recognized but it is still
uncertain whether obesity is the result or the cause of diabetes.

Diet:
Overeating, especially when combined with under activity, is associated with a
rise in the incidence of diabetes in the middle aged and elderly.

4.2. Secondary Diabetes:

a) Pancreatic diabetes is caused by
the destruction of the pancreases due to pancreatitis, carcinoma and pancreatic
calculi. b) Non-pancreatic diabetes occurs due to the abnormal concentrations
of hormones in the circulation i.e., in acromegaly, Cushing’s syndrome,
thyotoxicosis etc. c) Iatrogenic diabetes occurs after the prolonged use of
thiazide, diuretics, steroids, contraceptive pills etc.

Onset is usually gradual but rarely there may be acute onset,
the probable clinical features of diabetes are as follows: i) polyurea ii) polydipsia
iii) polyphagia iv) rapid emaciation v) dryness of mouth and threat vi) constipation.

Whenever diabetes is suspected, the
diagnosis should be confirmed by glucose tolerance test (GTT), by random blood
sugar sedimentation and by urine testing especially for glycosuria.

5. Method of treatment:

i) Diet regime

ii) Diet and oral hypoglycemic drugs
and

iii) Diet and insulin.

6. Drug management of diabetes

These are best suited for middle-aged
obese diabetics who would otherwise require insulin. There are several groups
of oral hypoglycemic agents. These agents with their derivatives are given below:

i. Insulin secretagogues (emission prompter of insulin): Sulphonylureas- 1. Aceloberamide, 2. chlorpropamide,
3. Glibenclamide, 4. Glibornuride, 5. Glimepiride, 6. Glimepiride amyral, 7 glipizide,
8. Glyburide, 9. tolazamide, 10. Tolbutamide, 11. Gliclazide, 12. Repaglinide,
13. nateglinide (last two are not chemically sulfonylureas).

ii. Insulin sensitizers (activity prompter of insulin): 1. Biguanides- metformin, 2. Thiazolidinediones- pioglitazone, rosiglitazone,
troglitazone.

iii. Disaccharides Inhibitors (inhibitors intestinal glucose absorption):
1. Acarbose, 2.
miglitol.

iv. Drug modalities Incretins exendin-4: 1. Liraglutide (subcutaneous
injection), 2. vildagliptin, 3. sitagliptin, 4. pramlintide (amylin analogues-subcutaneous
injection), 5. saxagliptin, 6. 
alogliptin.

Mechanism of action

Although
the mechanisms of action of these drugs are different, the action of first two
groups depends upon a supply of endogenous insulin. Sulphonylureas: These drugs act either by supressing the alpha cells
secretion, glucagons or by stimulating the beta cells to secret insulin. Biguanides: Mrtformin reduces hepatic
glucose production and increases peripheral glucose utilization.The mechanism
of action is still poorly understood (DeFronzo, 1991). Thiazolidinediones:.This class of agents works by increasing
insulin sensitivity. Acarbose: It is
effectively compensate for defective early-phase insulin release by inhibiting
the breakdown of disaccharides to monosaccharides in the intestinal epithelium
without any side effects.  The cell
surface serine amino peptidase enzyme, DPP-4, rapidly degrades and inactivates
GLP-1, GIP, and other peptides in vivo
via
cleavage of the N-terminal two amino acids. Inhibition of this
enzyme leads to an increase in circulating endogenous GLP-1 and GIP levels,
making it a promising therapeutic strategy for type 2 diabetes. The orally
administered DPP-4 inhibitors available and in development delay the breakdown
of incretin hormones, prolonging and enhancing their activity and thereby
increasing glucose-mediated insulin secretion and suppressing glucagon
secretion (Drucker, 2003).



Insulin
(11)

Insulin
is needed to keep the blood glucose within reasonable level without undue risk
of hyperglycemia. Two main therapeutic forms of insulin are available, namely

1.
Rapid-onset, short-acting and

Briefly
they are known as short-acting insulin and long-acting insulin.

Mechanism
of action

The basic
mechanism of insulin action is to increase the permeability of the cell
membranes of glucose. It is suggested that this change in permeability is
induced either by facilitating the conversions of glucose through
phosphorylation or oxidation into more lipid soluble compounds or by altering
the physical structure of the cell wall through the combination of the insulin
protein with the membrane protein, so that glucose can pass  more easily into the cell (Davidson, 1977).

Diabetes and the oxidative damage

The body maintains a balance between
the amount of reactive oxygen species generated and its antioxidant defense.
The balance may be tipped, however, by conditions that greatly increase the
generation of reactive oxygen species (such as cigarette smoke in the lungs)
and/or lack of antioxidant defense due to malnutrition.

There is substantial evidence that
people with diabetes tend to have increased generation of reactive oxygen
species, decreased antioxidant protection, and therefore increased oxidative
damage.

Hyperglycemia, or a high blood
glucose level, has been shown to increase reactive oxygen species and end
product of oxidative damage in isolated cell cultures, in animals with
diabetes, and in humans with diabetes. Measurement of the end products of
oxidative damage to body fat, proteins and deoxiribonucleic acid (DNA) are
commonly used to assess the degree of oxidative damage to body cells and
tissues. Most studies show that these measures are increased in people with
diabetes.

The activities of key antioxidant
enzymes are also to be abnormal in people with diabetes. In many studies, these
enzymes are also found to be lower than normal, suggesting a compromised
antioxidant defense, while other studies show higher activity, suggesting an
increased response to oxidative stress. Few studies demonstrate that oxidative
damage is greater in people with Type 2 diabetes compared with Type 1,
especially people with Type 2 diabetes and the metabolic syndrome, which
involves central obesity, hypertension (high blood pressure) and high blood fat
levels along with insulin resistance (decreased effectiveness of insulin
metabolizing blood glucose) suppressor (Internet III-I).  

7.0.
Survey of literature

Hypoglycemic agents are the materials
which are generally have opposite test to sweet and biologically possess
insulin like properties or act as a suppressor of glycemic level in blood. The
agents may be obtained from synthetic or plants (natural) sources.

7.1. Hypoglycemic
agents from synthetic origin

The hypoglycemic agents are either synthetic compounds or of animal origin (Table
3.1).

Table 3.1: Chronological list of
synthetic hypoglycemic agents

Hypoglycemic
agents

References/year

1

In
1908 the structural modification of sulfanilamides discovered from the dye
‘prontosil’ lead to synthesis of drugs for the treatment of diabetes
mellitus.

Zuelzer,
1908

(Williams,
2002)

2

Guanidine
which is generally administered in the form of its hydrochloride is an
effective hypoglycemic agent of the pre-insulin era.

3

With
discovery of insulin by Frederiech Grant Banting and Charles Herbert Best in
1921 treatment of diabetes was certainly boosted up.

1921,
Banting and Best

4

Jabon
et al in 1941-42 first observed that isopropyl-thiazole, a sulfonamide
derivative produced hypoglycemia in patients receiving the drug.

Jabon
et al. in 1941-42

5

Cyclopropyl
derivative of sulfonamide has hypoglycemic effect in normal rabbit but due to
its goiterogenic side effect the drug was not studied further.

Chen
et al., 1946

6

Sodium
salicylate and acetyl-salicylic acid were among the earliest drugs which
effectivelyreduce the total daily urinaryglucose output in diabetic patients.

Gross
et al., 1948

7

A
group of German researchers in 1954 found a sulfonamide derivative called
‘Carbutamide’ as the first effective synthetic anti-diabetic agent.  But the agent had severe toxicity problems
in a small percentage of the patients treated with this drug diminishing its
application.

German
researchers, 1954

8

With
discovery of glucose reducing (hypoglycemic) drugs carbutamide in 1955,
treatment of diabetes was certainly boosted up.

Franke
et al., 1955

9

Aspirin
has improved in the state of some of the diabetic patients given fairly large
doses.

Reid
et al., 1957

10

2,
4 Dinitrophenol reduces the fasting blood sugar in some diabetic patients and
increases glucose uptake by isolated rat diagragm.

Raudle,
1957

11

Discovery
of other synthetic agent known as ‘Tolbutamide’ in the same year with little
or no side effects became the first therapeutic agent in ‘adult-onset
diabetic patients

McMahan,
1963

12

Isopropyl-thiazole
opened up a new horizon in the field of treatment of diabetes mellitus with
synthetic agents

McMahan,
1963

13

Thiocarbonate
is as much effective hypoglycemic agent as tolbutamide when administered at a
dose of 25 mg/kg body weight

Doglas
et al., 1968

14

It
was observed that 1-phenyl-3-methyl-4-aryl hydrazone-2-pyrazolin-5-ones has
effective antidiabetic activity in experimental animals

Garg
et al., 1970

15

‘Benzimidazole’
derivatives of C12H16N4O3S,
having an aromatic nucleus with a side chain of ‘-SO2NHCONRR’ was
capable to reduce blood glucose level singnificantly after six hours of
administration

Deshpande
et al., 1970

16

Carburide,
a synthetic hypoglycemic agent has reported that the drug had no serious side
effect and enhanced the early release of insulin after oral glucose load in
patients

Joyce,
1971

17

The
hypoglycemic action of gliclazide, a sulfonylurea derivative was studied by
Furman and coworker. They found that glibenclamide when administered in
fasting rats decreases The plasma glucose and plasma FFA concentration were
decreased by glibenclamide when administered in fasting rats

Furman
et al., 1977

18

(N-(1-methyl-2-pyralidinyl-1-pyrralidine
carboximidamide) had hypoglycemic effect in non-diabetic rats, dogs, mice and
monkeys, which was structurally unrelated to sulfonylureas or phenformin

Thomas
et al., 1978

19

It
was experimentally found that pyrogliride potentials glucose induced insulin
secretion from isolated islets and facilitates glucoronic metabolism

Zawalich
et al., 1980

20

Saliman
et al. studied the
antidiabetic action of new 3-methyl-5-phenylpyrozole sulfonylurea derivative
in diabetic rats

Saliman
et al., 1981

21

First
biosynthetic human insulin is introduced

1983

22

Insulin
pen delivery system is introduced

1986

23

Troglitazone
[Rezulin, Resulin, Romozin] was introduced in the late 1990s but turned out
to be associated with an idiosyncratic reaction leading to drug-induced
hepatitis.

Internet
III-II

(2010)

All these
drugs control the pancreatic function. These drugs may causes hypoglycemia due
to toxic and adverse effect. This limits their use and prompted many
researchers to look into herbs and plants for less toxic hypoglycemic agents
for adult-onset diabetes or insulin non-dependent diabetes in particular.

7.2
Hypoglycemic agents from plant origin

The
hypoglycemic agents discussed so far are either synthetic compounds or of animal origin. But a
search for the discovery of hypoglycemic agents in plant kingdom has shown
promising results.

Ivorra et al studied the structure of 78 different compounds isolated from
plants with attributed hypoglycemic activity. They classified these compounds
according to the following chemical groups:


Polysaccharides
and proteins (59 compounds).

 
Steroids
and terpenoids (7 compounds).

 
 
Flavonoids
and related compounds (5 compounds) (Rahman et
al.
, 1989).

(List of some antidiabetic compounds is
given in the last column of Appendix-5 against the respective plant/plant
part(s) from which it was isolated).

Some plant originated hypoglycemic
agents are listed in Table 3.2.

Table 3.2: Chronological list of hypoglycemic agents from plant origin.

Hypoglycemic agents

References

1

Glucokenin,
an extract isolated from Cephalandra
indica
  has the property of
reducing the amount of sugar in the blood.

Collip,
1923

2

Galegine
(8), a guanide isolated from the
seeds of Galega officinalis, was
found to have a significant blood sugar lowering effect when administered by
mouth.

Muller,
H 1925

3

Gymnemic
acid (10), a glycosidic acid
isolated from Gymnema sylvetre
(Fam. Asclepiadaceae) was found to have a significant blood sugar lowering
effect when administered by mouth.

Muller,
H 1925

4

When
gymnemic acid is administered with insulin a prompt response was observed.

Morris
et al., 1976

5

Antihyperglycemic
effect of andrographolide in streptozotocin-induced diabetic rats.

Yu et al., 2006

6

Andrographolide-lipoic
acid conjugate (AL-1) had both hypoglycemic and beta cell protective effects
which translated into antioxidant and NF-?B
inhibitory activity. AL-1 is a potential new anti-diabetic agent.

Zaijun, et al., 2009

Plants in treating diabetes

Dolichos lablab
commonly known as field bean reduced the blood glucose level of diabetic
patient when administered for a long time (Nivasam, 1957).

The tablets made from leaves of Coccinia indica demonstrated the
hypoglycemic actions when administered at a dose of 3 tablets daily (Khan et al., 1980).The hypoglycemic effect of
the seeds Cyamopses tetragonoloba
Taub (Gower) on rabbits and found its action similar to tolbutamide at a dose
of 20 mg/kg bw. The effect, which was found to be due to extra pancreatic
action, was remarkable at 40 mg/kg.bw (Pilloi et al., 1980).

Similar investigations proposed that
hundreds of plants are known to be useful in the treatment of diabetes in
different corners of the world. According to Tanira more than 400 plants
incorporated in approximately 700 recipes are used to treat diabetes mellitus
in almost two thirds of the world population. In addition, clinical trials have
shown some plants as useful antidiabetic agents. The pure chemical compounds
isolated from the crude extracts of these plants do not bear structural
resemblance to the antidiabetic drugs in current clinical use nor have they
similar mechanisms of action. The search for a novel antidiabetic drug
advocates the utilization of plants as a potential source. Some research
approaches are suggested to increase the likelihood of isolating novel
hypoglycemic agents from plant sources.

Effectiveness of various herbs and
their products in the treatment of diabetes mellitus in our country are well
known. The scientific name of available indigenous plants seems to have
hypoglycemic properties is listed in Appendix-4 and another detailed list of
antidiabtic plants is enclosed in Appendix-5.

7.3. Hypoglycemic studies with
selected plants

7.3.1 Materials

For scientific investigation of
hypoglycemic activity, the selected plant materials are listed in Table 1.1.

These
plants have been used traditionally as folk medicines in treating various
diseases especially in diabetes by the common people but enough evidence was
not available to confirm the hypoglycemic activity of the various extracts on
different hyperglycemic conditions. Some evidences are listed in Table 3.3 with
references.

Table 3.3: List of hypoglycemic (antidiabetic)
evidence of the studied plants.

Plants/compound

Evidence

References

Screening for antihyperglycemic activity in
several local herbs of Malaysia


Husen et al., 2004

Antidiabetic
property of methanolic extract of A. niculata in streptozotcin rats

Zhang et al., 2000

Hypoglycemic
(diabetes), febrifuge, cholagogue, anthelmintic

Ahmed
et al., 1977

Andrographolide

(isolated
from A. 
paniculata
)

Antidiabetic

Ghani,
2003

Hypoglycemic

Ghani,
2003

Andrographolide
potentially reduced serum glucose in streptozotocin-induced diabetic rats.

Yu et al., 2006

Andrographolide-lipoic
acid conjugate (AL-1) had both hypoglycemic and beta cell protective effects
which translated into antioxidant and NF-?B
inhibitory activity. AL-1 is a potential new anti-diabetic agent

Zaijun, et al., 2009

Root
bark shows hypoglycemic and anthelmintic properties


Acharyya
et al., 2010

Hypoglycemic,
astringent, stomachic, antimalarial

Kitagawa
et al., 1996

Stem
bark shows hypoglycemic and anthelmintic properties

Ghani,
2003

S. sesban

Diabetes,
anthelmintic, catarrh, skin deases, stimulant, emmenagogue and galactogogue

Yadava
et al., 1996

M.oleifera Lamk. (Moringaceae) is commonly used as healing
herb to treat diabetes


Dolly et al., 2009

Others Materials

Albino rats
and Swiss albino mice were collect from Animal Breeding Center of BCSIR Laboratories, Chittagong. Long Evans rats were
procured from Animal House, BCSIR Laboratories and from
International Center for Diarrheal Disease Research, Bangladesh (ICDDR, B), and
naturalized in the animal house of the Faculty of Pharmacy department

The rats were fed on a good quality
basal diet and water ad libitum. The diet supplied to each rat was about
20 g of diet per day that was approximately isocaloric. The detailed
composition of the basal diet used for rats in the study has been given in
appendix-B.

Diactin (glipizide), daonil
(glibenclamide), glimepiride (SK& F),.

Diabetic inducers: Alloxan (Sigma Chemical Co., St. Lowis, MO), streptozotocin

Glucose kit:Human (Germany and
Accu-Check Active Meter, sanofi aventis)

Glucometer: EPS (Easy Pain Supreme, Bio
Technology Corp. Belgium]

Spectrophotometer: SPEKOL 1300, analylik jena

Basal diet: (Composition
Appendix-6)

Saline,
syringe, feeding tube, chloroforn, diethyl ether, cotton, Al-foil, gloves and
many more chemicals and laboratory apparatus.

7.3.2 Methods

Induction of diabetes in rats: Alloxan momohydrate/ tetrahydrate was dissolved in normal
saline and injected in the experimental rats to produce permanent diabetes
(juvenile type). The doses of alloxan, the degree of occurrence of diabetes in
rats and estimating blood/serum glucose level have been described thoroughly at
the related plant section.  



Albino rat Long Evans rat



Figure. 3.1 Photographs of rats

Figure 3.2: Photos of Swiss mice Figure 3.3: Administrationof test sample
in animals

Figure 3.4: Measuring of serum/blood
glucose by spectrophotometer and glucometer

7.3.3 Statistical analysis (Calculation):  Students `t’ test was formulated
for analysis of data from each experimental group. Percentage change in glucose
level (increased or decreased) was determined by using formula: (detailed in
Appendix 7).

(Average from control
groups -_average from treated
groups)

Average from control
groups

×100

7.4.  Hypoglycemic study with Andrographis paniculata

7.4 .1 Materials and its processing

Collection of plant material: The aerial
part of A. paniculata was
collected from the plantation area and neighboring hilly regions of BCSIR,
Chittagong, in the month of July 2006. The plants were cut into small pieces,
dried in the sun and then in an oven at 50oC for several hours. It
was then ground by means of an electric grinder to obtain a coarse powder.

Extraction of plant materials:

For preparing water extract the
powder of A. paniculata was mixed with distilled water (1:12), boiled
for 5-7 minutes, cooled at room temperature and filtered through a filter
paper.  The liquid (aqueous extract) was
then administered to rats through feeding needle.

The powder (900 g) of powder was
soaked in ethanol (4.5 L) in a large glass bottle that bearing a tap at the
lower part. It was left e for 7 days with occasional shaking. Then the liquid
extractive was passed through the tap and was filtered by using a filter paper.
The extract, so obtained was concentrated under reduced pressure at about 45-50oC
with a rotary vacuum evaporator.

Adult male and
female albino rats obtained from the Animal Breeding Center, BCSIR
Laboratories, Chittagong Bangladesh weighing 200-230 g were used for the study.
The rats were acclimatized to standard laboratory conditions (relative humidity
55
±5%, temperature 24±1oC and a 12 h diurnal photoperiod) in galvanized cages (3-6
rats/cage) with replaceable wire-meshed net lid for 7 days before the
commencement of the experiment. During the study, all animals were maintained
on normal laboratory chow and water
ad libitum.

Induction
of diabetes in rats:
In
glucose-loaded study, rats were fasted overnight (18 h) before oral administration
of glucose. Glucose at a concentration of 1.5 g/kg b.w. was dissolved in distilled
water immediately administratered through feeding needle. In alloxan induced
study, rats were injected with alloxan solution (40 mg/kg bw) intraperitonially
and then fasted for 18 hours.

2 Experimental design

Glucose-loaded experiments: 28 rats were randomly divided into four groups (7 rats in each gr.) as
follows-

Group I: Vehicle
control, received only distilled water

Group II:
Negative control, diabetic untreated (glucose, 1.5 g/kg bw)

Group
III: Positive control, diabetic treated with daonil  (4 mg/kg bw)

Group IV:
Positive control, diabetic treated with water extract (1 g/kg bw)

All the
animals were primarily fasted for 18 hours (given only distilled water) and
then glucose solution (group II to group IV) were given through feeding tube.
After 2 hours, distilled water, drug solution and sample (
water extract for one day’s
experiment and ethanol extract for another day’s experiment) were given orally
according to rats of respective group. Two hours later, all the animals were
anesthetized with diethyl ether and sacrificed and blood sample were collected
from cardiac vessel by syringe for every observation in each study.

28 rats were divided randomly and evenly as follows-

Group I: Vehicle control,
received only distilled water

Group II:
Negative control, diabetic untreated (alloxan, 40 mg/kg bw)

Group
III: Positive control, diabetic treated with diactin (4 mg/kg bw)

Group IV:
Positive control, diabetic treated with ethanol extract (1 g/kg bw).

The rats
of gr-II to gr-IV were injected with alloxan and all groups were fasted for 18
hours. Then standard drug and sample
(water extract for one day’s experiment and ethanol extract
for another day’s experiment), were given orally to the rats group wise in every experiment. Two
hours after treatment, blood samples were collected as described earlier.

Estimation of blood/serum glucose level (BGL): The level of glucose in blood samples from each of the experimental
and control rat was determined by using standard glucose kit essentially
following the glucose oxidase-peroxidase (GOD-POD) method (Barham,
et al., 1972; Trinder, 1969). The blood was taken by syringe from
cardiac vessels of sacrificed rats. It was then centrifuged to get a clear
supernatant (serum). 2
ml of
serum was taken in 2ml of standard glucose kit solution in a separate test
tube. The intensity of the color of the solution was measured with a
spectrophotometer at 546 nm for quantification of the glucose initially present
in the blood specimen.

7.5. Results and discussion
Effect of water extract on glucose-loaded hyperglycemic (GLH) rats: The effect of hot water extract on BGL of glucose-loaded rats is presented in Table-3.4.
Administration of glucose increased the BGL of rats by 89.47% as compared to
vehicle control rats while the hot water extract
A
. paniculata 
significantly
(p<0.001) decreased the elevated BGL by 41.51% as compared to diabetic
control (
glucose-loaded) rats.
In the case of standard drug, daonil treatment, the percent of BSL decrease was
44.70.

Effect of EE on GLH rats: The effect of EE on BGL of glucose-loaded rats has been summarized in Table-3.5. Administration of
glucose increased the rats BGL by 87.07% when compared to vehicle control rats.
On the other hand, rats treated with ethanol extract of
A. paniculata significantly (p<0.001)
lowered (41.82%) the enhanced BGL as compared to diabetic control
rats. In the case of drug (diactin) treatment group,
the glucose level was lowered by 45.63%.

on alloxan-induced
diabetic (AID) rats:
Table 3.6 depicts the
effect of hot water extract on BGL of alloxan-induced diabetic rats.
Administration of alloxan increased the rats BGL by 104.69% as compared to
vehicle control-control group. On the other hand, rats treated with hot water
extract of
significantly (p<0.001) lowered the elevated BGL by 46.21% when
compared to diabetic control

group. In this situation, the standard drug reduced the BGL by 49.66%.

Effect of EE on AID
rats: Table 3.7 shows the serum blood sugar level in
vehicle-control, diabetic control (alloxan), standard drug and sample treated
groups.

Table 3.4: Effect of hot water extract
of A. paniculata in GLH rats.

Group

Treatment

Blood
glucose levela Mean ± S.D (mg/dl)

Percent
change

­¯)]

I

Vehicle
control

60.77
± 3.28

II

Diabetic
control

115.14
± 2.36

?)

III

Drug
treated (Diactin)

63.67
± 3.05

44.70(?)

IV

Sample
treated

67.35
± 2.17

41.51(?)

Group

Treatment

Blood
glucose levela

Mean
± S.D (mg/dl)

Percent
change

­¯)]

I

Vehicle
control

61.40
± 3.34

II

Diabetic
control

114.86
± 1.62

?)

III

Drug
treated (Diactin)

62.45
± 4.02

45.63(?)

IV

Sample
treated

66.83
± 2.36

41.82(?)

Table 3.6: Effect of hot water extract
of A. paniculata  on AID  rats.

Group

Treatment

Blood glucose levela
Mean ± S.D (mg/dl)

Percent change

[Increased(­)/decreased(¯)]

I

Vehicle
control

60.22
± 3.19

II

Diabetic
control

123.27
± 3.68

?)

III

Drug
treated (Diactin)

62.31
±  5.18

49.66(?)

IV

Sample
treated

66.31
± 4.93

46.21(?)

Group

Treatment

Blood glucose levela

Mean
± S.D
(mg/dl)

Percent change

[Increased(­)/decreased(¯)]

I

Vehicle
control

61.21
±3 .25

II

Diabetic
control

125.24
± 3.19

?)

III

Drug
treated (Diactin)

61.30
± 3.06

51.05(?)

IV

Sample
treated

68.72
± 5.02

45.13(?)

Graphical
representation of the results is shown in Figure 3.5 to 3.8.

Figure
3.5

Figure
3.6

Figure
3.7

Figure
3.8

Figure 3.5: Chart for effect of water
exact in glucose-loaded hyperglycemic rats

Figure 3.6: Chart for effect of
ethanol exact in glucose-loaded hyperglycemic rats

Figure 3.7: Chart for effect of water
exact in alloxan-induced diabetic rats

Figure 3.8: Chart for effect of
ethanol exact in alloxan-induced diabetic 
rats

Table 3.8 Comparison of the effect of
hot WE and EE of A. paniculata on GLH
rats

Group

Treatment

hot water extracta

(Mean ± S.D), (mg/dl)

ethanol extract

(Mean ± S.D), (mg/dl)

I

Vehicle
control

60.77
± 3.28

61.40
± 3.34

II

Diabetic
control

115.14
± 2.36

114.86
± 1.62

IV

Sample
treated

67.35
± 2.17

66.83
± 2.36

%
 decreased

41.51

41.82

Table 3.9 Comparison
of the effect of hot WE and EE of A.
paniculata
on AID rats

Group

Treatment

hot water extracta

(Mean ± S.D), mg/dl)

ethanol extract

(Mean ± S.D), mg/dl)

I

Vehicle
control

60.22
± 3.19

61.21
± 3.25

II

Diabetic
control

123.27
± 3.68

125.54
± 3.19

IV

Sample
treated

66.31
± 4.93

68.72
± 2.02

%
decreased

——–

46.21

45.13

(N.B: All the above
results are average of 7 time experiments in each case)

Alloxan enhanced
the BGL by 104.61% when compared with vehicle-control rats. On the other hand,
treatment of rats with ethanol extracts were significantly (p<0.001)
decreased 45.13% the alloxan elevated BGL. Here, the blood glucose lowering
effect of the standard drug, diactin was 51.05%.

It is clearly
evident from the study that the aqueous and ethanol extractives were capable to
exhibit significant blood sugar lowering effects in both the glucose-loaded and
alloxan-induced diabetic rat (Table 3.4-3.7 and Figure 3.5-3.8). The lowering
of blood glucose levels by the aqueous extract was also comparable to methanol
extract. Both the extractives were found to able to reduce the sugar level
almost identically as evident from tables 3.8 and 3.9.

8.0. Hypoglycemic Study with Anthocephalus
chinensis

.1 Materials and its processing

Collection of plant materials: The
stem bark of A. chinensis was collected from Faridpur and was identified
at Bangladesh National Herbarium where a voucher specimen (# DACB 31749) has
been maintained. The barks were cut into small pieces, dried at room
temperature and then ground to a coarse powder.

Extraction of
plant materials:
The powdered bark was soaked
in methanol in a closed container for 7 days with occasional shaking. Then the
extractive was filtered by using a filter paper and concentrated under reduced
pressure at about 45-50oC with a vacuum rotary evaporator.
The concentrated extract so obtained was suspended in distilled water at
125 and 250 mg/kg b.w. (according to need) with the help of Tween 80. The
aqueous slurry was then administered to rats through feeding needle.

Animal and diet: Long Evans rats of either sex (100-200 g) were used for the investigation.
The rats were housed in standard conditions (relative humidity 55±5%, temperature
21±2oC) and a 12 h light-dark cycles and were given standard pellet
diet and water
ad libitum. Animals
were acclimatized to their environment for one week prior to experimentation.

8.2 Experimental Design

The 30 rats were
divided into five groups evenly as follows:

Group 1: Normal
control: given normal diet only

Group 2: Negative
control: diabetic untreated (alloxan, 150 mg/kg bw)

Group 3: Diabetic
treated with Glimepiride (200 µg/kg bw /body)

Group 4: Diabetic
treated with methanolic extract (125 mg/kg bw/day)

Group 5: Diabetic
treated with methanolic extract (250 mg/kg bw/day)

All rats except
normal-untreated group (gr-1) were injected with alloxan solution (150 mg/kg
bw) intraperitonially. After 48 h of injection, hyperglysomia was confirmed by
using electronic glucometer. The animals were treated with methanolic extract
for consecutive 7 days only as dose variation test and blood glucose was
measured every 24 hours after treatment.

Estimation of blood
glucose level (BGL):  The level of blood
glucose (sugar) of the experimental and control rats was rapidly determined by
using an electrochemical detection technique (Cass et
al
., 1984).

8.3 Results and discussion

In the present study, the hypoglycaemic potential of the methanolic
extract of A. chinensis was determined in alloxan-induced rats for 7 consecutive days (Table 3.10).
The study demonstrated that, the extracts were capable to reduce the elevated
blood sugar and the hypoglycaemic activity of the extract increased with the
increment of doses of the extractive.

The glucose levels obtained in blood of
normal and experimental rats are given in table 3.10 for plant extract. From table 3.11, it is evident that the methanolic extract of A. chinensis exhibited a significant
(p<0.05) reduction of blood glucose by 26.24% and 30.36% on 1st
day (24 hr after 0 time) for the dosing of samples 125 and 250 mg/kg bw/day
respectively, in diabetic rats as compared to the untreated diabetic rats (i.e.
1st day BGL of respective group). The BGL reduction capacity was
successively increased and at the end of 7th day, the highest values
obtained and it were 38.95% and 40.60% for the dosing of samples 125 and 250
mg/kg bw/day respectively, in diabetic rats as compared to the untreated
diabetic rats. Moreover, the lowest value (%BGL reduction) was obtained only by
26.24% for 125 mg/kg bw/day at the end of 1th day and the highest
value was 40.60% for 250-mg/kg b.w/day at the end of 7th day.

Table 3.10:
Effect of methanol extract of
A. chinensis on BGL in
AID rats

Group

mmol/L

Initial sugar level

1st  day

2nd  day

3rd day

4th day

5th day

6th
day

7th
day

Gr-1 Normal (untreated)

5.85±0.45

5.9±0.6

5.72±0.61

5.77±0.52

5.82±0.57

5.88±0.64

5.84±0.93

5.76±0.74

Gr-2: Diabetic control

19.8.±1.2

19.32±1.4

19.92±0.9

20.68±1.3

20.4±0.78

20.12±1.2

19.59±1.3

20.04±0.9

Gr-3: Glimepiride
treated

20.47±1.8

12.4±1.09

10.43±0.4

9.32±1.03

8.82±1.0

7.32±1.35

7.18±2.01

7.53±1.7

Gr-4: meth.  ext. treated (125 mg/kg b.w.)

19.82±1.8

14.62±1.6

14.09±0.9

13.33±1.3

13.14±1.5

12.95±1.6

12.46±0.8

12.1±1.9

Gr-5:meth. ext. treated
(250 mg/kg b.w. )

20.32±3.2

14.15±1

13.83±1.6

13.5±0.74

13.1±1.12

12.93±1.2

12.33±2.4

12.07±1.8

Table 3.11:
Percentage changes of BGL in AID rats by
extractives.

Treating Group and doses

% Reduction

1st  day

2nd day

3rd day

4th day

5th day

6th
day

7th
day

Gr-3:  Glimepiride

39.42

49.05

54.47

56.91

64.24

64.92

63.22

Gr-4: Methanolic extract
(125 mg/kg)

26.24

28.91

32.74

33.70

34.66

37.10

38.95

Gr-5: Methanolic extract
(250 mg/kg)

30.36

31.94

33.56

35.53

36.37

39.32

40.60

[N.B: % changes (reduction) of BGL of any days were calculated to
compare with 1st day BGL (mmol/L)

In conclusion
the experimental data suggests that the methanolic extract of A. chinensis has significant capability in reducing the elevated blood glucose
level (Table 3.11). The results so obtained, justify the folk use of the plant
for treatment of diabetes. Further comprehensive pharmacological investigations
are needed to elucidate the extract mechanism of the hypoglycemic potential and
long-term effects of the use of extractives in treating diabetes.

9. Hypoglycemic Study with Sesbania sesban

9.1 Materials and its processing

Collection
of plant material:
 The leaves of S. sesban were collected from plantation area of the BCSIR Laboratories,
Chittagong and were identified at the Plant Taxonomy Division and Bangladesh
national herbarium, where a voucher specimen has been deposited. The leaves were
dried at room temperature for some days, followed by drying in an oven and were
then ground to a coarse powder.

Extraction of plant material: The powder leaves were soaked in methanol in a closed container for 7
days. Then the extractive was filtered using a filter paper. The extract obtained
was concentrated under reduced pressure with a rotary vacuum evaporator.

Animal and diet: Adult male and
female Long Evans rats obtain from Bangladesh Council for Scientific and
Industrial Research, Dhaka weighing 120-210 g were used for the study. During
the study, all animals were maintained on normal laboratory chow, water
ad libitum.

Induction of diabetes in rats: Diabetes was induced in rats by injecting intraperitonially a freshly
prepared aqueous solution of alloxan (100 mg/kg b. w.), after a base line
glucose estimation was done. After 48 hours of alloxan administration, rats
with blood sugar levels above 14 mmol/L were selected for the study.

2 Experimental design

A total of 42 rats were
randomly divided in equal number into 7 groups.

Group A:
Normal untreated rats

Group B:
Alloxan induced diabetic (AID) rats (100 mg/kg bw)

Group C:
AID rats given glimepiride orally (200 µg/kg bw)

Group D:
AID rats given plant extract orally (50 mg/kg b w)

Group E:
AID rats given plant extract orally (100 mg/kg bw)

Group F:
AID rats given plant extract orally (200 mg/kg bw)

Group G:
AID rats given plant extract orally (300 mg/kg bw)

In this
study, at 0 time, all the rats of gr-B to gr-G were injected alloxan and  24 hours later, BGL of all group rats were
measured. After every 24 hours, rats of gr-C (glimeperide) and rats of gr- D to
gr-G were given drug and plant samples of respective amounts. The body weight
of all rats was assessed weakly. The blood samples of rats were drawn after an
over night fasting (12 hrs) from tail tip at different time intervals i.e., 1,
7, 14, 21 and 28th day for study with plant extract.

Estimation of blood glucose level: The blood glucose level of all were rapidly
determined by using a
electrochemical detection technique (Cass et
al.,
1984
) and described in the respective section of A. chinensis.

9.3 Results and discussion

Diabetes induced rats produced a
significant reduction of body weight in all hyperglycemic rats. The
administration samples improved the body weight significantly (p<0.05) after
28 days as compared to diabetic control groups (Table 3.12). It was evident
that the daily administration of different doses of methanolic extract for 28
days revealed a statistically significant (p<0.05) increase in body weight
when compared with diabetic control rats. On the other hand, no significant
body weight anomaly was observed between glimepiride and the samples treated
groups.

The glucose levels obtained in blood of normal
and experimental rats are given in table 3.13 for plant extract. From table 3.14, it is evident that the methanolic extract of S. sesban showed a significant
(p<0.05) reduction of blood glucose by 10.0%, 22.61%, 24.17% and 27.80% on 7th
for the dosing of samples 50, 100, 200 and 300 mg/kg bw/day respectively, in
diabetic rats as compared to the untreated diabetic rats (i.e. 1st
day BGL of respective group). We observed that the glucose lowering activity
was higher in higher doses of samples. In the same way, reduction capacity was
successively increased day by day and at the end of 28th day, the
highest values were obtained and it was 25.48%, 46.29%, 51.88% and 53.12% for
the dosing of samples 50, 100, 200 and 300 mg/kg bw/day respectively, in
diabetic rats as compared to the untreated diabetic rats.

Groups

Dose

mg/kg

Body
weight in g

1st
day

7th
day

14th
day

21st
day

28th
day

A-
Normal- untreated

—-

±2.98

±3.63

±3.66

±3.9

±3.8

B-
Alloxan treated

100

±4.3

±4.7

±3.9

±5.1

±4.2

C-
Glimepiride treated

0.2

±5.2

±4.8

±5.3

±5.1

±5.5

D-
zMeth ext treated

50

±3.65

±1.9

±2.4

±3.7

±2.8

100

±1.8

±2.2

±2.3

±3.3

±2.1

200

±3.5

±3.2

±2.8

±2.3

±2.2

G- ,, ,,

300

±2.7

±2.9

±3.0

±2.5

±3.1

Values are given in average body weight g±SEM for groups of six animals
each. *p<0.05

effect of 4 weeks
treatment of methanol extract S. sesban on BGL in AID rats.

Groups

Dose

mg/kg

BGL
in mmol/L

1st
day

7th
day

14th
day

21st
day

28th
day

A-
Normal-untreated

—-

±0.38

±0.45

±0.45

±0.48

±0.39

B-
Alloxan treated

100

±0.12

±0.09

±0.11

±0.08

±0.07

C-Glimepiride
treated

0.2

±0.20

±0.22

±0.19

±0.26

±0.23

D-
Met. ext. treated

50

15.7±0.57

14.13±0.24

13.28±0.46

12.25±1.15

11.7±0.51

100

15.08±1.77

11.67±1.96

10.13±1.43

9.27±1.27

8.1±1.39

200

14.4±1.73

10.92±0.7

9.38±0.52

7.86±0.69

6.93±4.32

G- ,, ,,

300

14.1±0.56

10.18±2.0

8.32±0.61

7.15±1.03

6.1±0.95

Values
are given as mean ±SEM for six animals in each group.

Diabetic
control (Group B) was compared with normal group (Group A) on corresponding
day.

Experimental
groups (Groups D-G) were compared with diabetic control group (Group B) on
corresponding day.*p<0.05; **p<0.001

Table 3.14: Effect of leaves
methanolic extract of
S. sesban on BGL of AID rats

Group

Dose

mg/kg

% Reduction

7th day

14th day

21st 
day

28th day

C: Glimepiride treated

0.2

60.63

66.46

70.11

73.54

D –Met. ext.
treated

50

10.0

15.41

21.97

25.48

E –   ,, ,,

100

22.61

32.82

38.53

46.29

F – ,, ,,

200

24.17

34.86

45.42

51.88

G- ,, ,,

300

27.80

40.99

48.26

53.12

Experimental groups (Groups D-G) were compared with diabetic control
group on corresponding day.

The above experimental data suggests that the methanolic
extract of S. sesban was highly capable in lowering the blood glucose
level in alloxan-induced hyperglycemic rats. Thus the folk use of the plant for
treatment of diabetes is justified. However extensive pharmacological
investigations are needed to elucidate the exact mechanism of the hypoglycemic
potential and long term effect of the use of samples in treating diabetes.

10.
Hypoglycemic Study with Moringa oleifera

1 Materials and its
processing

Collection of plant materials:The stem bark of M. oleifera was collected from Rajbari and was identified at the Plant Taxonomy
Division of Dept. of Botany, University of Dhaka. The chops of bark were dried
at room temperature for some days, followed by drying in an oven and were then
ground to a coarse powder.

Extraction
of plant materials:
 The powdered M.
oleifera
was soaked in methanol in a
closed glass bottle for 7 days. The extractive was filtered byusing a filter
paper. The extract so obtained was concentrated under reduced pressure with a rotary vacuum evaporator.

Animal
and diet:
Adult male and female Long Evans
rats purchased from Bangladesh Council of Scientific and Industrial
Research, Dhaka weighing 120-180 g were used for the study. During the study,
all animals were maintained on normal laboratory chow and water
ad libitum.

Induction
of diabetes in rats:
Diabetes was
induced in rats by injecting intraperitonially a freshly prepared aqueous solution
of alloxan monohydrate  (150 mg/kg b. w.)
after a base line glucose estimation was done. 

.2 Experimental design
A total of 36 rats were
randomly divided in equal number into 6 groups as following protocol. It is
dose dependant study.

Group I:
Normal untreated rats

Group II:
Alloxan induced diabetic (AID) rats (150 mg/kg bw)

Group III:
AID rats given glimepiride orally (200 µg/kg bw/day)

Group IV:
AID rats given plant extract orally (100 mg/kg bw/day)

Group V:
AID rats given plant extract orally (200 mg/kg bw/day)

Group VI:
AID rats given plant extract orally (400 mg/kg bw/day)

The study
was carried over for 3 consecutive weeks and the body weight was assessed
weakly. The blood samples of rats were drawn after an over night fasting (12
hrs) from tail tip at different time intervals i.e., 1st  (after 48 hrs of 0 time or base line measure),
7th , 14th  and 21st
day for study with plant extract.

Estimation
of blood glucose level:
 The level of blood glucose (sugar) of the
experimental and control rats was determined by using standard glucose test kit
based on the glucose oxidase method. The blood of every rat was taken on strip
by puncturing the tail tip.

10.3
Results and Discussion

Diabetic rats showed a significant
reduction of body weight in all hyperglycemic rats. The administration of M.
oleifera
extract improved the body weight significantly (p<0.05) after
21 days as compared to diabetic control groups (Table 3.15).

The glucose levels obtained in blood of
normal and experimental rats are given in table 3.16 for plant extract. From tables 3.17, it was evident that the methanolic extract of M. oleifera showed a significant (p<0.05) reduction of blood glucose by 16.47%, 21.62%
and 22.66% on 1th for the dosing of samples 100, 200 and 400 mg/kg
bw/day respectively, in diabetic rats as compared to the untreated diabetic
rats (i.e. after 48 hrs BGL of diabetic induction of respective group). We
observed that the glucose lowering activity was higher in higher doses of
samples. In the same way, reduction capacity was successively increased day by
day and at the end of 21th day, the highest values were obtained and
it was 24.47%, 27.10% and 28..02% for the dosing of samples 100, 200 and 400
mg/kg bw/day respectively, in diabetic rats as compared to the untreated
diabetic rats. Moreover, the lowest value (%BGL reduction) was obtained only by
16.47% for 100 mg/kg bw/day at the end of 48 hrs base measuring (1st
day) and the highest value was 28.02% for 400-mg/kg b.w/day at the end of 21th
day.

Table 3.15: The changes in body weight of treated and
untreated rats

Groups

Dose
mg/kg

Body
weight in g

1st
day

7th
day

14th
day

21st
day

I-
Normal-untreated

——-

±1.98

±3.60

±2.56

±4.9

II-
Alloxan treated

150

±4.32

±3.44

±3.35

±4.1

III
Glimepiride treated

0.2

±5.21

±4.8

±5.35

±5.2

IV-Met.
ext.  treated

100

±4.45

±1.75

±2.37

±3.8

V- ,, ,,

200

±1.8

±2.28

±3.2

±3.6

400

±3.5

±3.1

±2.8

±2.4

Values
are given in average body weight g
±

effect of 3 weeks treatment of ME of M. oleifera on BGL in AID rats.

Groups

Dose

mg/kg

BGL
in mmol/L

After
48 h of dosing

1st
day

7th
day

14th
day

21st
day

I-
Normal-untreated

as
reqd

4.88±0.49

5.60±0.60

5.32±0.61

4.91±0.52

5.4±0.57

II-
Alloxan treated

150

18.35.±1.21

19.22±1.40

19.72±0.95

20.60±1.12

20.12±0.53

III
Glimepiride treated

0.1

19.59±1.73

13.40±1.09

9.43±0.48

8.32±1.03

7.82±1.00

IV-Met.
ext.  treated

100

18.72±1.46

15.62±1.62

15.09±0.93

14.33±1.6

14.14±1.10

V- ,,
 ,,

200

19.33±2.27

15.15±1.33

14.83±1.62

14.5±0.97

14.1±1.81

400

19.42±1.31

15.02±2.17

14.74±1.01

14.11±0.96

13.97±1.52

Values
are given as mean
±SEM for six animals in each group.

Diabetic
control (Group II) was compared with normal group (Group I) on corresponding
day.Experimental groups (Groups IV-VII) were compared with diabetic control
group (Group II) on corresponding day.

Table 3.17:  Effect of stem bark extracts of  M. oleifera on
BGL in AID rats.

Group

Dose

mg/kg

Reduction, %

1st day

7th day

14th day

21th day

III
–Drug

0.1

31.60

51.86

57.53

60.08

IV-Sample

100

16.56

19.39

23.45

24.47

V
–   ,,

200

21.62

23.27

23.99

27.10

VI
– ,,

400

22.66

24.10

27.34

28.02

Experimental
groups (Groups IV-VII) were compared with diabetic control group on
corresponding day.

 

Conclusion

Water and ethanolic exrtact of A. paniculata, methanolic extracts of A. chinensis, S. sesban and M. oleifera
were subjected to investigate the hypoglycemic activity. In the case of
glucose-loaded rats; hot water extract of A.
paniculata
, exhibited the glucose lowering efficacy (41.51%) and ethanol
extract by 41.82%.  In AID rats blood
glucose decreasing efficacy was 46.21% by hot water extract and 45.13% by
ethanol extract. After
consecutive five days treatment with
the 125 mg/kg.bw/day and 250 mg/kg.bw/day of bark extract of A. chinensis, the BGL lowering capability in the elevated blood glucose level were found
38.95% and 40.60%, respectively.

Leaves extract (300-mg/kg/day) of S. sesban possess excellent blood
glucose reducing properties (53.12%). From table 3.9 & 3.10, it is evident
that the methanolic extract showed a significant blood glucose reduction by 25.48%,
46.29%, 51.88%, and 53.12% on 28th day, respectively for 50, 100,
200 and 300 mg/kg bw/day in diabetic rats as compared to the untreated diabetic
rats.

Bark exact of M. oleifera exhibited moderate hypoglycemic activity in this
experiment with maximum fall of blood glucose of 28.02% for 400 mg/kg bw/day at
the end 21th day. Diactin (glipizide, marked drug) and glimepiride (active)
were used as positive control in this study. At a dose of 4 mg/kg bw, diactin
showed a fall of glucose level by 51.05%, whereas glimepiride exhibit a decrease
of glucose level by 60.08% to 73.54% in different experiment.

In this study, some of the
parameters and doses of extractives are different in some extent.

Moreover the experiments with above extractives,
two isolated compounds from S. sesban
leaves exact, like oleanolic acid and 7-methoxy genistein (isoflavone) are
known to possess potential antidiabeic and antioxidant properties (Matsuda et al., 1998, Mapanga et al., 2009). Long-term oral
administration of genistein significantly inhibits retinal vascular leakage in
experimentally induced diabetic rat (Masami et
al
., 2001).

In in vivo studies also, pretreatment of
rats with oleanolic acid displayed significant (p<0.05) antihyperglycemic
activity in starch tolerance test however, administration of starch fortified
with oleanolic acid to the rats could not exhibit antihyperglycemic activity (Tiwari
et al. 2. Oleanolic acid glycosides exhibit their
hypoglycemic activity by suppressing the transfer of glucose from the stomach
to the intestine and by inhibiting glucose transport at the brush border of the
small intestine [Chem Pham Bull (Tokyo
), 1998].