1,2
pertension, hyperlipediemia, hypercholesteromia, insulin resistance and glucose
tolerance are known as cardiac risk factors that cluster in obese individuals3.
The persistence of hypercholesteromic state causes enhanced oxidative stress,
leading to the development of atherosclerosis, coronary artery disease and other
complications of obesity4 Obesity is associated
with many health problems including coronary heart disease, diabetes, kidney
failure, osteoarthritis, back pain and psychological damage. Diseases such as
hypothyroidism, insulin resistance, polycystic ovary syndrome and Cushings
syndrome are also contributors to obesity. The strong association between obesity
and cancer has only recently come to light5.
Tecoma stans (Common name: Yellow bell) is also known as yellow trumpet
bush and belongs to the family Bignoniaceae. It is an erect ornamental plant
and is a branched, slightly hairy or nearly smooth shrub 2 to 4 m in height.
The leaves are opposite, odd-pinnate and up to 20 cm in length with 5 to 7 leaflets.
The leaflets are lanceolate to oblong-lanceolate, 6 to 13 cm long, pointed at
both ends and toothed on the margins. The trumpet-shaped flowers are yellow,
faintly scented and occur in short, dense, terminal clusters. The calyx is green,
5 to 7 mm long and 5-toothed. Flowering can begin as early as April and continue
into the fall (autumn)6. The leaves of
T. stans contain the alkaloids tecomine and tecostamine, potent hypoglycaemic
agents when given intravenously. Anthranilic acid is responsible for its antidiabetic
activity and the roots exhibit a powerful diuretic and vermifuge activity7.
Tecoma is not toxic and is used in Latin America as a remedy for diabetes and
also for feeding cattleand goats in Mexico8.
The present study was planned to investigate anti-obese and anti- hyperlipidemic
activity of flower extract of T. stans.
MATERIALS AND METHODS
Collection of plants and preparation of extracts: The flowers of T. stans
were collected in the month of May 2011 from Rasipuram (Namakkal District) Tamil
Nadu. A herbarium specimen of the plant was deposited in the Department of Pharmacognosy.
The plant was identified by Dr. G.V.S. Murthy, Joint Director of the Botanical
Survey of India, Southern circle, TNAU Campus.
Coimbatore, who authenticated the plant from information available in the literature.
The flower petals were dried in the shade and then powdered and 100 g of the
dried powder was extracted with ethanol using a soxhlet apparatus. The solvent
was removed under reduced pressure and controlled temperature using a rotary
flash evaporator. Phytochemical screening of the extracts revealed the presence
of tannin, flavonoids, phenols, alkaloids, steroids, triterpenes and saponins.
Animals: Wister rats (150-170 g) of both sexes were used in these experiments
and they were housed under standard environmental conditions like, ambient temperature
(25±1°C),
relative humidity (55±5%)
and a 12/12 h light dark cycle. Animals had free access to a standard pellet
diet and water. All animal experiments were carried out in accordance with the
guidelines of CPCSEA. The animal ethical committee of the institute gave its
approval to conduct the animal experiments (approval No. 1158/ ac/07/CPCSEA).
PHARMACOLOGICAL STUDIES
Atherogenic diet induced obesity in experimental rats preparation of diet:
Atherogenic Diet (AD) is a hyper caloric diet and was prepared by mixing the
following constituents in fixed percentage. The mentioned percentage is for
100 g diet. The feed was prepared, dried and administered every day in morning
to animals with water ad libitum9.
Atherogenic diet formula:
• |
Cholesterol: 1% |
• |
Cholic acid: 0.5% |
• |
Olive oil: 5% To be provided in addition to the normal pellet chow
everyday for 42 days |
Experimental design: Female albino wistar rats (150-170 g) were divided
into five groups of six rats each. The following schedule of dose and diet administration
in experimental groups was followed:
Group 1: |
Animals fed with normal diet and served as normal control |
Group 2: |
Animals received Atherogenic diet (1% cholesterol) and served as Obese
contol |
Group 3: |
Animals received Atherogenic diet+sibutramine (2 mg kg-1 b.wt.)
suspended in 0.9% saline |
Group 4: |
Animals received Atherogenic diet+METS (100 mg kg-1) suspended
in 0.9% saline |
Group 5: |
Animals received Atherogenic diet+METS (200 mg kg-1) suspended
in 0.9% saline |
The above mentioned treatment schedule was followed for the respective groups
of animals for 42 days.
Pharmacological evaluations
Body weight: The body weight (g) was recorded on day one and then
on every week for 42 days using digital weighing balance.
Body temperature: The body temperature was recorded on day 41 using
rectal telethermometer before and after drug administration at 30, 60, 90, 120,
180 min with a contact time of 1 minute.
Biochemical estimations: On day 43, animals were sacrificed under anesthesia
and blood was collected by direct cardiac puncture. Blood samples collected
are to be centrifuged at 3500 rpm for 15 min at room temperature for separation
of serum. The clear, non-haemolysed supernatant sera will be separated using
clean dry disposable plastic syringes and parameters such as Total cholesterol,
Triglycerides, HDL, LDL, VLDL11, Atherogenic
index (AI)10, percentage protection, SGOT,
SGPT, total protein, Blood glucose12 and
Urea were evaluated:
Estimation of internal organ weight: The animals were sacrificed and
the organs like heart, liver and both the kidneys were separated out and blotted
in a filter paper and immediately weighed in a digital balance.
Statistical analysis: All the results were expressed as mean±standard
error of mean and were analyzed by Analysis of Variance (ANOVA) and groups were
compared by Tukey-Kramer multiple comparison test. Differences between groups
were considered significant at p<0.05 level.
RESULTS
Effect of METD on Body weight: Utilization of Atherogenic Diet (AD) for
six weeks produced a significant (p<0.001) augment in body weight when compared
with the consumption of normal control group (normal pellet chow). Treatment
with METS at the dose of 200 mg kg-1 causes a significant reduction
(p<0.001) initiated from the second week, whereas sibutramine also abridged
the increased body weight. Changes in the body weight in the different group
of animals, during the experiment is given in Table 1.
Effect of METD on body temperature: Animals fed with atherogenic diet
exhibited decrease in body temperature. Sibutramine exhibited reverse effect
by increasing the body temperature significantly (p<0.001) (Table
2). METS at both the doses (100 and 200 mg kg-1)
upturned the decrease in body significantly (p<0.01 and p<0.001), respectively
at various time intervals.
Table 1: |
Effect of methanol extract of Tabernaemontana
divaricata on body weight of atherogenic diet induced obese rats at
different days interval |
 |
Values are Mean±SEM for six groups of six animals each, Values
are statistically significant at *p<0.05, **p<0.01 and ***p<0.001when
group 2 compared with group 1 and groups 3-5 were compared with group 2 |
Table 2: |
Effect of Methanol extract of Tabernaemontana
divaricata on body temperature of atherogenic diet induced obese rats
at different time interval on day 41 |
 |
Values are Mean±SE for six groups of six animals each, Values are
statistically significant at *p<0.05, **p<0.01,***p<0.001
when group 2 compared with group 1 and groups 3, 4 and 5 were compared with
group 2 |
Table 3: |
Effect of methanol extract of Tabernaemontana
divaricata on lipid profiles of atherogenic diet induced obese rats
on day 42 |
 |
Values are Mean±SEM for six groups of six animals each, Values
are statistically significant at *p<0.05, **p<0.01, ***p<0.001
when group 2 compared with group 1 and groups 3, 4 and 5 were compared with
group 2 |
Effect of METD on lipid profile: Group 2 (Obese control group) animals
fed with AD exhibited a significant (p<0.001) increase in Total Cholesterol
(TC), Triglycerides (TG), LDL and VLDL when compared with group I (normal group)
animals. Administration of METS (200 mg kg-1)
and sibutramine shows a noteworthy reduction (p<0.001) in TC, TG, LDL and
VLDL when compared with the group 2 animals, whereas decreased HDL levels noted
in group 2 animals were significantly (p<0.05) increased in group 4 (Table
3).
Atherogenic index (AI) and percentage protection: Decline in Atherogenic
Index was observed in all the treated groups (group 3 to 4). Percentage defense
for METS (100 and 200 mg kg-1)
was 24.63 and 48.30%, respectively and 49.51% for sibutramine treated group.
(Table 4).
Effect of METD on liver function tests: Levels of SGOT, SGPT and total
protein increased significantly (p<0.001) in group II animals. Group 3 and
4 exhibited a significant (p<0.001) decrease when compared with group 2 animals
(Table 5).
Table 4: |
Effect of methanol extract of Tabernaemontana
divaricata on atherogenic index and percentage protection of various
groups |
 |
Effect of METD on blood glucose and urea: Major reduction of urea and
lift up in blood glucose levels was observed in obese control animals (group
3). METS (200 mg kg-1)
shows a significant decrease in blood glucose (p<0.01) and increase in urea
levels (p<0.001) when compared to group 2 (Table 5).
Effect of METD on inner organ weight: Feeding AD for six weeks twisted
a significant increase in the weight of liver, heart and both of the kidneys.
Treatment with METS significantly reduced the weight of liver, heart and kidneys
(Table 6).
DISCUSSION
High proportion of fat in artherogenic diet (Cholesterol 1%) is considered
to be an important factor inthe development of obesity, leading to the accretion
of body fat.
Table 5: |
Effect of Methanol extract of T.stans on SGOT, SGPT, total protein, urea and blood glucose levels of Atherogenic
diet induced obese rats on day 42 |
 |
Values are Mean±SE for six groups of six animals each, Values are
statistically significant at *p<0.05, **p<0.01, ***p<0.001when
group 2 compared with group 1 and groups 3, 4 and 5 were compared with group
2 |
Table 6: |
Effect of methanol extract of T.sans on inner organ weights of atherogenic diet induced obese rats on day 42 |
 |
Values are Mean±SE for six groups of six animals each, Values are
statistically significant at *p<0.05, **p<0.01, ***p<0.001 when
group 2 compared with group 1 and groups 3, 4 and 5 were compared with group
2 |
The present tudy showed that the administration of AD for six weeks in rats
shaped obesity-like conditions, with augment in body weight, parametrial adipose
tissue mass and organ mass and serum lipid levels. It also induces to the amassing
of hepatic triglycerides, leading to the hepatic failure causing boost in SGOT
and SGPT levels in the serum. In obesity, there will be diminish in the diet
induced thermogenisis, due to lessen in sympathetic activation of brown adipose
tissue. Neuropeptide-Y (NPY), which synthesized in the brain causes increase
in food intake and also inhibits thermogenisis by plummeting sympathetic activation
of brown adipose tissue2. Treatment with
METS at doses of 100 and 200 mg kg-1, significantly abridged the
increased body weight induced by AD, which shows a clear indication of an antiobesity
effects.
In fatness there will be an increase in serum lipids, such as Total Cholesterol
(TC), Triglycerides (TG), LDL-C and VLDL-C were pragmatic in humans and also
a diminution in HDL-C levels. Variation in lipid levels is also painstaking
as an index of obesity13. Low plasma HDL-C
is a risk factor for cardiovascular diseases and is often found in hypertension
and diabetes mellitus14,16.
Administration of METS caused a significant correction of elevated TC, TG, LDL-C
and VLDL-C and increases the serum HDL-C shows that, METS has a agreeable antihyperlipedimic
activity. Lipids are mostly consumed in the form of neutral fats, which are
also acknowledged as Triglycerides (TG). TGs form major constituents in food
of animal derivation and fewer in food of plant source. Saturated fats increase
blood cholesterol and thereby increase risk of atherosclerosis and coronary
heart diseases, abnormal lipoprotein metabolism, obesity, insulin resistance
and diabetes mellitus15,17.
Atherogenic index is the powerful indicator of the risk of heart disease: the
higher the value, the higher the risk of developing cardiovascular disease and
vice versa18,19.
In this study we observed that the METS significantly reduced atherogenic index,
indicating the fortification against cardiovascular diseases20.
The capacity of the hepatocytes in obese rats to produce urea from precursors
is decreased and the uptake of amino acids by liver and the hepatic activity
of the enzymes of the urea cycle are also decrease21.
Hence, there will be a lesson in the urea level in obese rats and the METS treated
animals showed a significant reverse activity. The liver uses transaminase enzymes,
ALT (SGPT) and AST (SGOT) to metabolize amino acids and to build proteins. When
liver cells get dented, ALT and AST leak into the blood stream. Fatty liver
is also a reason for the hepatic damage and frequent causes of fatty liver are
Diabetes, Obesity and alcohol abuse (www.medicinenet.com).
Also, obesity is related with the increase adipose tissue buildup in the abdominal
region. It is reported that METS produced decrease in the weight of liver, heart
and kidney similar to that of the standard drug sibutramine22.
Further investigation involving measure of enzymes in lipid pathways and harmones
would ascertain the exact mechanism and figure out the therapeutic potential
of Tecoma stans in the treatment of hyperlipedimia and obesity. However
further studies under progress to isolate and characterize the phytoconstituents
responsible for the above activities. " target="_blank">View Fulltext
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