Important of diabetes, the leaves of this

Important medicinal plants
having antidiabetic potential

Gymnema sylvestre

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

Gymnema sylvestre (Asclepiadaceae) plant
species with Indian origin is emerging as a potential treatment for the
management of diabetes, the leaves of this plant are used for the preparation
of antidiabetic herbal drugs. Widely used across
India and parts of Asia as a natural treatment for diabetes. The plant’s crude
extracts and it’s isolated compound dihydroxy gymnemic triacetate show
hypoglycemic against streptozotocin induced diabetic rats in dose and time
dependent manner (Daisy et al.,
2009). This hypoglycemic effect was due to the ability of gymnemic acids to
delay the glucose absorption in the
blood. Because gymnemic acid molecules fill the receptor location in the
absorptive external layers of the intestine, thereby preventing the sugar
molecules absorption by the intestine, which results in a low blood sugar
level. And also the reduced glucose levels are exerted by the crude extraction
due to the presence of dihydroxy gymnemic triacetate had the ability to release
the insulin by the stimulation of a regeneration process and revitalization of
the remaining beta cells. (Liu et al.,
2009) also demonstrated the Gymnema
sylvestre aqueous extract of leaves stimulates insulin secretion from mouse
cells and isolated human islets in vitro,
without compromising cell viability. The plasma glucose and insulin level
of the normal rats administered with dihydroxy gymnemic triacetate were not
altered indicating it’s normal glycemic effect of the novel compound. The
characteristic loss of body weight associated with STZ- induced diabetes is
associated with muscle reduction in diabetes. With such studies, it can
conclusively be affirmed that dihydroxy gymnemic triacetate which was isolated
from the leaves of Gymnema sylvestre represent
as a potential medicine for the management of Diabetes mellitus, since they
exhibited beneficial effects on the 
blood glucose level and associated biochemical parameters of STZ induced
diabetic animals (Rao et al., 2010).

Bauhinia
forficata

Bauhinia forficata extensively used as
an herbal medicine for control of Diabetes in Brazil, where it is known as Pata
de Vaca (Cow’s hoof). The essential part of this plant which shows the
hypoglycemic activity are the fresh leaves of these plants. As per an experiment carried
out, (Pepato et al., 2002) Bauhinia forficata decoction was
prepared by boiling 150 g of fresh leaves in 1 litre of water for 5 minutes,
allowed the decoction to stand for 30 minutes and filtered. The rats, which
were used for the experiment were fed with normal chow diet containing (w/w)
16% protein, 66% carbohydrate and 8% fat and were housed under a 12:12 hour
light: dark cycle at 22- 25°C . In this experiment the rats were
divided into two groups, i.e.
diabetic and non diabetic groups, followed by administered the streptozotocin
40 mg kg-1 body weight, after 3 days the serum and urinary glucose
were increased. Then one group was injected with Bauhinia forficata decoction and another with drinking water as the
control group. After 31 days of treatment the diabetic group of rats treated
with decoction showed a significant reduction in plasma glucose and urinary
glucose (Rao et al., 2010).

Ricinus communis

Ricinus communis is the traditional medicine,
which was used for the management of Diabetes mellitus. It is known as Erandah
in Sanskrit, Arandi in Hindi and is also known as Castor oil. It belongs to the family Euphorbiaceae,
cultivated all over India for getting it’s seed oil. Fifty percent of ethanolic
extract of the root, stem and leaves
of this plant showed hypoglycemic activity in normal animals and
antihyperglycemic activity in diabetic animals in initial screening studies.
The administration of the ethanolic
extract for a long duration led to a significant reduction of blood glucose
amongst diabetic rats, while there was no significant alteration in the blood
glucose of control animals. The 50% ethanolic root extracts of Ricinus communis showed a dose dependent
effect on blood glucose of diabetic animals up to dose of 500 mg kg-1
body weight. On the other hand, higher doses up to 2000 mg kg-1 body
weight did not show up any dose dependent effect and a maximum decrease in
blood glucose was observed at 8th hour. The significant hypoglycemic
effect was observed at 500 mg kg-1 body weight of 50% ethanolic
extract which decreases the blood glucose to 166 ± 19 from the initial level
371 ± 21 mg dl-1. Out of twenty column purified fractions of 50%
ethanolic extracts were tested for antihyperglycemic activity in diabetic rats,
only one fraction (R18) showed a
significant decrease in blood glucose of the diabetic rats. Fraction (R18)
decreased the blood glucose to 294 ± 60 (22.4% decrease), 284± 36 (25%
decrease), 184 ± 23 mg dl-1 (51.4% decrease), 182 ± 40 mg dl-1 (51.9% decrease), 149 ± 11
mg dl-1 (60.6% decrease) at 1st, 2nd, 4th,
6th and 8th hour, respectively from an initial value of 379 ± 72 mg dl-1 at the beginning
of the experiment. The results of this
plant showed a potent blood glucose lowering activity both in normal as well as
alloxan diabetic rats. The effective dose of Ricinus communis was found to be 500 mg dl-1 body
weight. Administration of this ethanolic extract to diabetic rats for 20 days,
not only significantly lowered the blood glucose of the diabetic animals to almost normal level, but also increased
the insulin levels and caused improvement in lipid profile and body weight of
the diabetic animals. It therefore seems to have a promising value for the
development of a potent phytomedicine for diabetes (Rao et al., 2010).

Swertia
punicea

Swertia punicea plants native to Japan
are most widely used traditional medicines in the treatment of Diabetes.
Administration of Swertia punicea extract
and the methylswertianin and bellidifolin fractions of the extract to Type 2
diabetic mice improved insulin sensitivity (Tian et al., 2010).

        The
mechanism involved increased expression of key proteins insulin receptor,
insulin receptor substrate -1 and phosphatidylinositol 3- kinase that are
involved in the insulin signaling processes. Additionally, methylswertianin and
bellidifolin decreased the activity of glucokinase and increased the activity
ofglucose-6-phosphate, enzymes that are involved in the secretion of insulin
from pancreatic ? cells (Coman et al.,
2012). The herbal medicine Swertia
punicea plays an important role in the management of Type 2 diabetes
mellitus and supports the development of new phytomedicine for this deadly
disease (Rao et al., 2010).

Combretum
micranthum

Combretum micranthum is a medicinal plant used for treating Diabetes in
Northwestern Nigeria. Commonly known as ‘Geza’ in Hausa, belong to the family
of Combretaceae. The plants have also been documented to show antioxidant,
antimicrobial as well as anti inflammatory properties. The aqueous extract of
Combretum micranthum was prepared by using
Soxhlet extractor and was dried in an evaporator at 45°C and stored
at 4°C until ready for use. The hypoglycemic activity of this plant
extract was tested by using a glucose
tolerance test and fasting blood sugar assessment in normal rats. The anti
hyperglycemic potential of the plant was performed by taking two groups of animals diabetic group and a non diabetic
group. The aqueous leaf extract of Combretum
micranthum dissolved in normal saline and administered to both the groups
at 100 mg kg-1, 200 mg kg-1 and 400 mg kg-1
body weight, but 100 mg kg-1 body
weight of the extract was found to be the optimum dose out of the three doses. The aqueous leaf extract of 100 mg
kg-1 body weight dose produced a significant reduction in blood glucose level and 24.6% maximum
reduction when compared to the maximum decrease of 21.9% and 18.9% produced 200
mg and 400 mg kg-1 body
weight doses, respectively (Chika & Bello, 2010). In this study the aqueous
leaf extract of Combretum micranthum was
proved to have anti diabetic property for both Type 1 and 2 diabetes mellitus (Rao et
al., 2010).

Sarcoporium
spinosum

Sarcoporium spinosum is a common
medicinal plant in the Mediterranean region; it is widely used as an
antidiabetic drug by Bedouin healers. Several studies were performed to show
that the root extract of Sarcoporium
spinosum exhibits a hypoglycemic effect on rats. The aqueous root extract
of Sarcoporium spinosum was prepared
by cutting the 100 g of fresh roots into small pieces and they were boiled in a
litre of water for 30 minutes. The aqueous extract was used to carry out the
experiment in 0.001-10 mg dl-1 concentrations. The Sarcoporium spinosum extract exhibited
insulin like effect on glucose uptake in hepatocytes by inducing a 148 ± 10,
133

± 23 and 119 ± 14% increase in glucose uptake
respectively, compared to 160 ± 12% increase in glucose uptake obtained by
insulin. The root extract of this plant at 0.001 mg ml-1
concentration showed maximum activity than lower or higher doses. The aqueous
root extract was assumed that it showed antidiabetic effect in the progressive
hyperglycemia of genetically diabetic mice. Hence, the aqueous root extract of Sarcoporium spinosum shows insulin like
actions on target tissues, increases insulin secretion in vitro, and have an improved tolerance in vivo (Smirin et al.,
2010). The identification of active compounds in the Sarcoporium spinosum plant
extract may  be a source for the
development and improvement of new antidiabetic drugs (Rao et al., 2010).

Parinari
excelsa

Emerging as a potent antidiabetic
herbal drug option, Parinari excelsa, family
Chrysobalanaceae is one of the most widely used medicinal plants. In Africa, it
is found in Guinea, in Congo and in Senegal particularly in Casamance. Parinari excelsa bark is used for the
treatment of Diabetes mellitus. (Jayaprakasam et al., 2005) studies show that
the flavonoids of the bark of this plant shows the hypoglycemic effect and has
the ability to induce insulin secretion 
in diabetic animal models. The aqueous bark extract was prepared by using 25 g dried and powdered barks and these were infused in 200 ml of aqueous
ethanol (3.1) for overnight. After that the infusion is subjected to filtration
and the solvent was evaporated to give the extract. The hypoglycemic activity
of this plant was studied with two groups of animals; alloxan induced diabetic
and normal glycemic rats. The aqueous extract is then administered to both the
groups at doses of 100 and 300 mg kg-1 day-1 for a week.
The antidiabetic activity of extract was performed on overnight fasting rats.
The plant’s aqueous extract at 100 and 300 mg kg-1 day-1
reverse the permanent hyperglycemia induced by alloxan and the blood glucose
level decreased from 3.11±

    
to 0.91 ± 0.02 g l-1 and
3.60 ± 0.12 to 0.85 ± 0.04 g l-1, respectively. The oral
administration of aqueous extract of Parinari
excelsa at 100 and 300 mg kg-1 also showed significant reduction
in blood glucose level in 30 minutes from the time of consumption (Rao et al.,
2010).

Vernonia anthelmintica

The popular name of this plant is
wild cumin/purple/worm seed and in Hindi it is known as ‘Kalizeeri’. Belonging
to the family Asteraceae, Vernonia
anthelmintica is found throughout India and an annual herbaceous plant. The
ethanolic extract of this plant seeds has an hypoglycemic effect in
streptozotocin induced diabetic rats. The ethanolic extract was prepared by using
200 g powdered seeds and these were extracted with a litre of 95% ethanol in a
soxhlet extractor for 24 hours. The antidiabetic activity of this plant was determined using the
glucose peroxidase method. The ethanolic extract of the plant at a dosage of 0.25 and 0.75 g kg-1 body  weight showed a decrease of 30.6% and 17.5%
in the blood glucose level of the diabetic rats after 6 hours of treatment,
respectively. A dosage of 100 mg kg-1 body weight of the extract
showed a significant antihyperglycemic activity in the diabetic treated rats
with a maximum fall of 82.3% in the blood glucose level after 6th hour of treatment when
compared to other fractions (Fatima et al.,
2010).

Elephantopus
scaber

Elephantopus scaber is a traditional
medicinal plant, having the property to reduce the blood glucose levels in
streptozotocin induced diabetic rats significantly. It is popularly known  as Elephant’s foot and belongs to the
Asteraceae. It is a scabrescent
aromatic herb distributed in the moist deciduous forests of the central Western
Ghats. The acetone
extract of the plant was Prepared from 1 kg dried, powdered
plant and was extracted using hexane, acetone and methanol in a soxhlet
extraction apparatus sequentially and the extracts were evaporated to dryness
under reduced pressure. After 60 days of treatment with the acetone extract of Elephantopus scaber, showed a
significant reduction in blood glucose level from the initial 534.6 mg dl-1
to 86.14 mg dl-1 and reached a level closer to the untreated control
of 85.6 mg dl-1 (Daisy et al.,
2009). The antidiabetic property of plants shows their mechanism by improving
insulin sensitivity, augmenting glucose dependent insulin secretion and
stimulating the regeneration of islets of langherhans in pancreas of
streptozotocin induced diabetic rats.

The administration of Elephantopus scaber acetone extract
lowering the blood sugar level in streptozotocin induced hyperglycemic animals
it may be due to stimulating effect on insulin release from regenerated ? cells
of the pancreas or increased cellularity of the islets tissues and regeneration
of the granules in the ? cells. The significant and consistent antidiabetic
effect of acetone extract of the plant in diabetic rats indicates that this
effect can be mediated by stimulation of glucose utilization by peripheral
tissues.

Liriope
spicata

Liriope spicata is a medicinal plant
native to China and Vietnam belongs to
Liliaceae family, frequently used as a treatment for Diabetes mellitus due to its
high availability and safety. The plant possesses the antidiabetic property due
to two important active components in
water as well as crude polysaccharides. The aqueous extract of Liriope spicata tuberous roots was
prepared by using 500 g of powdered material and it was boiled in distilled
water for three times 1:4, 1:4, and 1:2 in w/v for half an hour each time.
Afterwards the extract was filtered, combined and then concentrated by using a rotary
evaporator at 45ºC under reduced pressure. The aqueous extract was administered
at a dose of 100 mg kg-1 and
200 g kg-1 to both control and diabetic rats. After 28 days of
treatment the blood glucose level in streptozotocin induced diabetic rats was
decreased. But, it did not show any marked results on fasting blood glucose in
normal mice (Chen et al., 2009; Rao et al.,
2010).

Artemisia
dracunculus L.

Artemisia dracunculus L. has been
reported by several researchers for possessing hypoglycemic effects (Ribnicky et al., 2009; Wang et al., 2011). It was found that Artemisia dracunculus L. improved insulin sensitivity and IR
signaling in insulin-resistant KK-Ay mice models. They could not explain the
cellular mechanism behind the effect. The suggestion given was the modulation
of skeletal muscle protein degradation and phosphate activity. 4, 5-Di-O-
caffeoylquinic acid, 6-demothoxycapillarisin and 2′, 4′-
dihydroxy-4-methoxy-dihydrochalcone were isolated from the ethanolic extract of
the above mentioned plant. The compounds showed inhibitory effects toward the
enzyme aldose reductase, a key enzyme involved in diabetic complications, which
may explain the antidiabetic effect. The bioactive components in Artemisia dracunculus L. also include
davidigenin, sakuranetin and 5-O-caffeoylquinic acid (Eisenman et al., 2011; Coman et al., 2012).

Present scenario, challenges and
future prospects of plant based medicine worldwide

Presently, all over the world, there
is an increasing awareness towards herbal medicine. This has resulted in an
increase in funds for research and establishment of new departments such as
herbal science department. There are numerous trials
being carried out to find out more alternatives for this slow poisoning
disease (Subramoniam, 2014). Some notable medicines which are scientifically
validated but not clinically proven due to lack of proper information and
documentation are Allium cepa, Zingiber
officinale, Momordica charantia. There are numerous like these plants
facing a challenge of limited taxonomy, efficient testing, proper trials and
documentation. Some notable plants under clinical trial are Cannabis indica, Clerodendron phlomoides,
and Withania somnifera (Chawla et al., 2013).

Challenges with herbal
drugs

Herbal drugs are prescribed widely because
of their effectiveness, less side effects, broad range of action and relatively
low cost. However, there are certain facts that pose great challenges for complete
changeover with synthetic drugs. Non trial drugs are usually not evaluated for
purity and consistency of active compounds. Moreover, lack of standardization
keeps it an alarming mode about the after effects of the drug after consumption
without proper prescriptions.

The various shortcomings of herbal medicines primarily include-

1.                
Self prescribed or prescribed by
unauthorized organizations.

2.                
Quality assurance is not guaranteed
and also may interact with other drugs.

3.                
active ingredients can change in different
environmental conditions.

4.                
Contains powerful pharmacologically
active compounds that need to be evaluated for drug-drug interactions.

5.                
Difficulty in identification of the
causative agent associated with adverse reactions encountered as these may
contain multiple ingredients.

6.                
Mode of action of herbal plant
constituents is not clear enough to support therapeutic utility (Chawla et al.,
2013).

 

Safety is a major concern with herbal
medicines as due to lack of proper documentation of major segments of information
which are still not available. As
their consumption without proper guidance can not only be harmful with long term or short term effects but could also
be fatal in certain situations. Today with the discovery of alternative
medicine pathways it is also very much essential
to maintain a proper database
rather a proper segment which could
systemize the information gathered along with synchrony with its testing and
validation and open new doors for a more safer and efficient drug discovery and
implantation.

FUTURE PROSPECTS

 

It is likely that an increasing
awareness of the effectiveness of herbal medicine alternatives will lead to a
significant increase in patient’s growing interest and understanding towards
these resources. As mentioned proper testing and documentation will lead to a
massive development and pace to this particular sector. Plants under trial such
as Cannabis indica, Clerodendron
phlomoides, and Withania somnifera, their proper study and documentation
will result in providing many more such options. Diabetes mellitus is a slow
poisoning disorder which slowly engulfs the functioning of essential and vital organs in such a scenario
providing greater options are only possible when specific or target groups are
dedicated towards the development of alternative medicines. Diabetes has a multifactorial
pathogenicity, thereby requiring multimodal management approach. Today
integrated herbal drug development model are being proposed and are being
constantly developed in order to provide a strong backbone of understanding the
herbal formulations and their effects. Hand in hand with regularizing  databases will be the most effective tool for
enabling implantation of herbal alternatives at a faster pace. Another very
important facet is herbal drug standardization which requires inputs from
various branches including botanists, plant physiologists, chemi-informatics,
biochemistry, pharmacology, drug development, etc. Along with these further studies are warranted with
these models to ensure effective drug usage and guide the future research
endeavors in a more systematic way (Chawla et
al., 2013).

CONCLUSION

 

Pharmacological and Phytochemical
evaluation is an integral and essential part of drug development. Antidiabetic
herbal options which are available are mostly easily and locally available
herbal options. Today when more and more people are focusing upon and adapting
herbal formulations, their proper evaluation and documentation is of utmost
priority. In such a scenario the Pharmacological and Phytochemical study of
antidiabetic herbal plants provides concrete information about the therapeutic
utility and active compounds, required for the drug formulation. Proper
documentation will enable to study better alternatives with greater
information. With constant researches and improvements herbal medicines can
turn up to be a better alternative which is both cost effective and possess
lesser side effects. Considering various herbal options and there availability
various researches at regular intervals are also taking place thereby the
article turns out to be as a helpful source of information which can act as a
helping guide towards a systematic approach.