Evaluation of Antiulcer Activity of Coccinia grandis Leaves.

 

C. Girish3*, S. Vineela1, Y. NarasimhaReddy2, O.V.S. Reddy3, K.K. Rajasekhar4 and V. Shankarananth4.

3 Dept of Biochemistry S.V. University, Tirupati.517-501.

1 MAM College of Pharmacy, Narsaraopet, Guntur.

2University College of Pharmaceutical Sciences, Kakatiya University, Warangal.

4 Sri Padmavathi School of Pharmacy, Tirupati.

ABSTRACT:

The anti-ulcer activity aqueous extract of leaves of Coccinia grandis was investigated in pylorus ligation and ethanol induced ulcer models in experimental rats. In both models the common parameter determined was ulcer index. Aqueous extract of Coccinia grandis at doses of 250 and 500 mg/kg  produced significant inhibition of the gastric lesions induced by pylorus ligation induced ulcer and ethanol induced gastric ulcer .The extract (250 mg/kg & 500 mg/kg) showed significant (P<0.05) reduction in gastric volume, free acidity and ulcer index as compared to control. This present study indicates that aqueous extract of Coccinia grandis have potential anti- ulcer activity in the both models. These results may further suggest that the extract was found to possess antiulcerogenic as well as ulcer healing properties, which might be due to its antisecretory activity.

 

KEYWORDS: Coccinia grandis, Pylorus ligation, Ethanol induced ulcer model, Ulcer index, Omeprazole.

 

 

INTRODUCTION:

Peptic ulcer disease is one of the most common gastrointestinal disorders, which causes a high rate of morbidity1. Peptic ulcer is a conglomerate of heterogenous disorders which manifests itself as a break in the lining of the gastrointestinal mucosa bathed by acid and/or pepsin NSAID ingestion is associated with erosions, petechiae type C gastritis, ulceration interference with ulcer healing, ulcer complications and injury to the small and large intestine2. In recent years, a powerful association between peptic ulcers and infection of Helicobacter pylori has been adopted. At least 70-90% of patients with gastric ulcers and 80-95 % with duodenal ulcers are infected by H pylori and eradication of this microorganism seems to be curative for the disease3.

 

Although a number of antiulcer drugs such as H2 receptor antagonists, proton pump inhibitors and cytoprotectants are available, all these drugs have side effects and limitations4. Herbal medicine deals with plants and plant extracts in treating diseases. These medicines are considered safer because of the natural ingredients with no side effects5. Screening plants for active drugs is still important and might provide a useful source of new anti-ulcer compounds for developing pharmaceutical drugs or alternatively as simple dietary adjuncts to existing therapies6.

 

Coccinia grandis is one of the traditional indigenous plants of India and is widely distributed.  It is commonly used as anti-inflammatory, aphrodisiac, antipyretic, anti- spasmodic, galactagogue, expectorant, astringent and anti-leprotic7.

 

MATERIALS AND METHODS:

Plant material:

The leaves of Coccinia grandis were collected from in and around the Tirumala hills, Tirupathi, Andhra Pradesh in the month of June, 2010. The collected leaves were washed with tap water to remove adhering dust followed by distilled water and shade dried and size reduced into small pieces. Dried materials were coarsely powdered and macerated with water for 72 hrs. The final extract was filtered, dried and collected.

 

Animals:

The study was conducted on male Wister rats (175 – 200 gm) housed in polypropylene cages under standard conditions of temperature (22 ± 2şC), relative humidity (60 ± 5%) and light (12h light/ dark cycle) were used.  They were fed with standard pellet diet and water. The food was withdrawn 18 hours before the experiment but allowed free access of water. All animal experiments were carried out in accordance with the guidelines of CPCSEA.

 

Acute oral toxicity studies:

Acute toxicity study was carried out according to Organization of Economic Co-Operation and Development (OECD) guidelines8. No mortality was observed and all the test doses were found to be safe.

 

Pyloric ligation in rats:

The animals were divided into 5 groups, each consisting of six rats. Control group received distilled water only. Second group of rats are pyloric ligated. Third and fourth groups received aqueous extract of Coccinia grandis in a dose of 250 and 500 mg/kg. The fifth group of animals received Omeprazole in the dose of 20 mg/kg as a reference drug for ulcer protective studies. After 45 min of the treatment, pyloric ligation was done by ligating the pyloric end of stomach of rats of respective groups under ether anesthesia at a dose of 35 mg/kg of body weight. Ligation was done without causing any damage to the blood supply of the stomach. Animals were allowed to recover and stabilize in individual cages and were deprived of water during post-operative period. Rats were sacrificed after 4 h of surgery and ulcer scoring was done. Gastric juice was collected and gastric secretion studies were performed according standard procedure 9.

 

Ethanol induced ulcer model:

The ulcer was induced by administering absolute ethanol (1ml/200g.). All the animals were fasted for 36 hours and then ethanol was administered to induce ulcer. The animals were divided into five groups, each consisting of six rats. The control group received distilled water, second group received ethanol. Third and fourth groups received aqueous extract of Coccinia grandis in a dose of 250 and 500 mg/kg. The fifth group of animals received Omeprazole in the dose of 20 mg/kg as a reference drug. They were kept in specially constructed cages to prevent coprophagia during and after the experiment. The animals were anaesthetized 1h latter with anaesthetic ether and stomach was incised along the greater curvature and ulceration was scored. A score for the ulcer was studied similar to pyloric ligation induced ulcer model10.

 

Scoring of ulcer:11.

Normal stomach                   -0

Red coloration                     -0.5

Spot ulcer                             -1

Hemorrhagic streak              -1.5

Ulcers (< 2mm)                    -2

Ulcers (>2<4) Perforation    -3

Ulcers (>4mm)                     -4

Mean ulcer score for each animal was expressed as ulcer index. The percentage of ulcer protection was determined by

% of ulcer protection =

Control mean ulcer index - Test mean ulcer index   × 100

                   Control mean ulcer index

 

Determination of free acidity:

Acidity =

Volume of sodium hydroxide ×Normality ×100mEq/L/100g

                                         0.1

 

Statistical analysis:

The values are represented as mean ± S.E.M, and statistical significance between treated and control groups was analyzed using of one way ANOVA, followed by Dennett’s test where P<0.05 was considered statistically significant.

 

RESULTS:

Pyloric ligation induced gastric ulcer:

In pyloric ligation induced ulcer model, oral administration of aqueous extract of Coccinia grandis in two different doses showed significant reduction in ulcer index, gastric volume, free acidity, total acidity as compared to the control group. Aqueous extract of Coccinia grandis exhibited a protection index of 69.7 % and 82.2 % at the dose of 250 and 500 mg/kg respectively,whereas omeprazole as reference standard exhibited a protection index of 86.2 %(Table-1).

 

Ethanol-induced gastric ulcer:

In control animal, oral administration of absolute ethanol produced characteristic lesions in the glandular portion of rat stomach which appeared as elongated bands of thick, blackish red lesions.Aqueous extract of  Coccinia grandis has shown significant protection index of 68.7 % and 72.2 % with the dose of 250 and 500 mg/kg respectively whereas ,omeprazole as reference standard showed protection index of 80.6 %(Table-2).

 

 

Table:-1 Effect of aqueous leaf extract of Coccinia grandis on various parameters in pyloric ligation induced gastric ulcers.

Group

Treatment

Ulcer index

Free acidity      meq/ltr

PHof gastric

Juice

Gastric   juice (ml)

Total acidity meq/ltr

Protection

(%)

I

Normal

(Distilled water)

----

42.4±0.3

5.42±0.3

3.7±0.4

61.3±0.2

----

II

Control

(Pyloric ligation)

15.2±1.2

96.7±1.2

2.61±0.2

9.2±0.2

113.6±0.2

----

III

Aqueous extract of  Coccinia grandis

(250 mg/kg)

4.6±0.5

44.7±0.3

4.97±0.2

5.4±1.2

76.3±0.4

69.7%

IV

Aqueous extract of  Coccinia grandis (500mg/kg)

2.7±0.4*

40.8±0.2*

5.61±0.4*

4.2±0.4*

62.7±0.6*

82.2%

V

Omeprazole

(20 mg/kg)

2.1±0.5*

39.4±0.2*

5.72±0.2*

3.9±0.2*

60.1±1.4*

86.2%

 

Table:-2 Effect of aqueous leaf extract of Coccinia grandis on various parameters in ethanol induced gastric ulcers.

Group

Treatment

Ulcer index

PH  of  gastric juice

Protection (%)

I

Normal

(Distilled water)

----

5.37±0.3

----

II

Control

(Pyloric ligation)

13.4±0.2

2.93±0.9

----

III

Aqueous extract of  Coccinia grandis (250 mg/kg)

4.2±0.5

3.78±0.6

68.7%

IV

Aqueous extract of  Coccinia grandis (500mg/kg)

3.7±0.4*

4.96±0.8*

72.2%

V

Omeprazole

(20 mg/kg)

2.6±0.4*

5.62±0.7*

80.6%

Values are expressed as mean ± SEM of observations, Statistical comparisons as follows: Significant *p<0.05 compared to control group.

 

 

 

DISCUSSION:

The etiology of peptic ulcer is unknown in most of the cases, it is generally accepted that gastric ulcer results from an imbalance between aggressive factors and the maintenance of the mucosal integrity through the endogenous defense mechanism12. Different therapeutic agents are used to inhibit the gastric acid secretion or to boost the mucosal defence mechanisms by increasing mucosal production, stabilising the surface epithelial cells or interfering with the prostaglandin synthesis13. The prostaglandins can provide gastric cytoprotection in rats against strong necrotizing irritants without reducing gastric acid secretion14.

 

The causes of gastric ulcer by pyloric ligation are believed to be due to stress induced increase in gastric hydrochloric acid secretion and/or stasis of acid and the volume of secretion is also an important factor in the formation of ulcer due to exposure of the unprotected lumen of the stomach to the accumulating acid. The ligation of the pyloric end of the stomach causes accumulation of gastric acid in the stomach. This increase in the gastric acid secretion causes ulcers in the stomach. The lesions produced by this method are located in the lumen region of the stomach 15.

 

Ethanol induced gastric lesion formation may be due to stasis in gastric blood flow which contributes to the development of the haemorrhage and necrotic aspects of tissue injury16.  Alcohol rapidly penetrates the gastric mucosa apparently causing cell and plasma membrane damage leading to increased intra cellular membrane permeability to sodium and water. The massive intracellular accumulation of calcium represents a major step in the pathogenesis of gastric mucosal injury. This leads to cell death and exfoliation in the surface epithelium17.

 

In the present study aqueous extract of Coccinia grandis showed protection against gastric lesions in the experimental rats. Aqueous extract of Coccinia grandis reduced the gastric volume, free acidity, total acidity and ulcer index thus showing the anti-secretory mechanism involved in the extract for their anti-ulcerogenic activity. Ulcer index parameter was used for the evaluation of anti-ulcer activity since ulcer formation is directly related to factors such as gastric volume, free and total acidity18.

 

The protection of aqueous extract of Coccinia grandis against characteristic lesions may be due to both reductions in gastric acid secretion and gastric cytoprotection or enhancement of the mucosal barrier through the increase production of prostanglandin and this may be due to the presence of flavonoids. Further studies are needed for their exact mechanism of action on gastric acid secretion and gastric cytoprotection.

 

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Received on 07.12.2010

Accepted on 06.02.2011     

© A&V Publication all right reserved

Research J. Pharmacology and Pharmacodynamics. 3(2): March –April, 2011, 92-95