Anti-Ulcer Effects of Ipomoea aquatica forsk Leaves against Gastric Ulcers in Rats

P. Muthukumaran¹* and K. Pattabiraman²

¹P.G. Dept .of Biochemistry, Meenakshmi Chandrasekaran Arts and Science College, Pattukkottai 614 601, Thanjavur, Tamilnadu, India

²Department of Siddha Medicine, Faculty of Science, Tamil University, Vakaiyur, Thanjavur - 613 010, Tamilnadu, India.

ABSTRACT:

The anti ulcer effects of aqueous, chloroform and ethanol extracts prepared from the Ipomoea aquatica forsk leaves was evaluated in rats employing the pylorus ligation, stress induced and aspirin induced models. The parameters taken to assess anti ulcer activity were volume of gastric juice, free acidity, total acidity and ulcer index. The results indicated that chloroform extract significantly (p<0.001) decreased the volume of gastric acid secretions, free acidity and total acidity and ulcer index.

KEYWORDS: Ipomoea aquatica forsk Antiulcer effect, Pylorus ligation, Aspirin, Stress

INTRODUCTION:

Ipomoea aquatica forsk belongs to the family Convolvulaceae grows wild and is cultivated throughout Southeast Asia and is a widely consumed vegetable in the region. Many of the waters where IAF grows serve as recipients for domestic and other types of wastewater. Water spinach is also supposed to possess an insulin-like activity according to indigenous medicine in Sri Lanka (Malalavidhane, T.S et al, 2000). Only a very few scientific studies have been conducted on its medicinal aspects. These include the inhibition of effects on liver diseases. (Badruzzaman, S.M. et al 1992), constipation (Samuelsson, G et al 1992). It is runner type plant with numerous small flowers. (Merrill, E.D.1917. Merrill, E.D 1939, Van Ooststroom, S.J1940, Van Ooststroom S.J et al 1953) A study of efficacy of different extracts of Ipomoea aquatica forsk against gastric ulcers with three models in rats is an effort made in the same direction.

MATERIALS AND METHODS:

Plant material:

The fresh leaf’s of IAF was collected from (Thanjavur, Tamilnadu, India) Southern Ghats of South India during June 2008.The specimen voucher was deposited in the Department of Environment and Herbal science Tamil university, Thanjavur.

Preparation of extract:

400 gm of powder was suspended in 500ml of distilled water at room temperature. The mixture was sieved through a muslin cloth, followed by filtration using filter paper. The filtrate was mixed with chloroform in a separating funnel and shaken until separation was observed in two layers. The extract of two layers were run out into separate beaker and placed in an oven to dry at 50ºC. Residues of extracts were made into suspensions using sterile distilled water and chloroform in concentration of 100 mg/ml. Ethanolic extract was also prepared similarly (Muhammad, H.S et al 2005).

Animals:

Albino-Wister rats of either sex weighing between150-200 g were used. The animals were acclimatized for 10 days before and during study in the Central Animal House of Department of Siddha Medicine Tamil University Thanjavur under standard conditions at room temperature of 24±2 C, relative humidity of 45-55% and 12:12 light/dark cycle. The animals were fed with standard rodent pellet (Sai Durga Feeds and Food, Bangalore, India (Pranav Agro Industries Ltd., Sangli, India). Water was supplied ad libitum under stricthygienic conditions. The Institutional Animal Ethics Committee, Department of siddha medicine Tamil university Thanjavur approved the protocol of the study. All the chemicals used were of analytical grade.

Acute Toxicity:

Acute toxicity studies of henna extracts were performed on rats and the lethal dose was estimated using the method described by Miller and Tainter (Miller, L.C et al 1994).

EXPERIMENTAL PROCEDURE:

Animals were divided into five groups (n=6). Group-I received 2% gum acacia that served as control, group-II received ranitidine orally (20 mg/kg), group-III, IV and V received aqueous, chloroform and ethanolic extracts (1g/kg) respectively

Study of antiulcer activity using pylorus ligation method:

The method of Shay et al.1945, was adopted. Animals were fasted for 24 h and the dose was administrated30 min prior to pylorus ligation. Animals were sacrificed 4 h later and the stomach was removed .The gastric content was collected and centrifuged. The volume, free acidity, total acidity of gastric fluid was determined. The stomach was then incised along the greater curvature and observed for ulcers. The number of ulcers was counted using a magnifying glass. Mean ulcer score for each animal was expressed as ulcer index. The ulcers were graded using the following scoring system- 0= Normal mucosa; 0.5= Red coloration; 1.0=Spot ulcer; 1.5=Hemorrhagic streaks; 2.0=Ulcere”3 mm but d”5mm; 3.0=Ulcer e” 5 mm

Study of antiulcer activity using stress induced Ulcers:

The method of Nagura 1972 modified by Bacchi 1988 was adopted. Animals were fasted for 24 h before the experiment. The animals were treated with respective dose. They were anaesthetized with ether .Both upper and lower extremities were fixed together and the animals were wrapped in a wire gaze. They were horizontally suspended in the dark at 20°C for24 h, and finally sacrificed. The stomach was removed and severity of ulcers was registered and the ulcer index was calculated as mentioned earlier.

Study of anti ulcer activity using aspirin induced ulcers:

The method of Hedge et al., 1994 was adopted. The animals were treated with respective dose of 8 days as mentioned in previous model. After 8 days of treatment animals were fasted for 24 h. ulcer was induced by administration of aqueous suspension of aspirin (200 mg/kg) 4 h later. The animals were sacrificed and stomach was opened to calculate the ulcer index as given earlier.

Phyto-chemical analysis:

The leaves Ipomoea aquatica forsk extract (chloroform) was analyzed using TLC plates (0.1 mm thick silica gel) eluted with ethyl acetate-glacial acetic acid- water (100:11:1126).The spots were identified under short wave UV light.

Statistical analysis:

The results of the above experiment are indicated in terms of Mean ± SEM. Statistical difference between mean were calculated using one-way analysis of variance followed by Dunnet’s ‘t’ test, p<0.05 were considered statistically significant.

RESULTS AND DISCUSSION:

Traditionally medicinal plants have been used in folk medicine throughout the world to treat various diseases, especially gastric ulcers. We evaluated preventive effects of aqueous, chloroform and ethanol extracts obtained from henna leaves in animals using the different standard experimental models of induced gastric ulcers. Pylorus ligation model resulted the accumulation of gastric secretary volume and an increase in the total acid output of the gastric juice .Circular and linear lesions were frequently seen in the stomach of all the control animals. Administration of henna extracts resulted in a significant reduction in ulcer index when compared with control (Table-1). Although in most of the cases the aetiology of the u ulcers is unknown, it is generally accepted that it results from an imbalance between aggressive factor and the maintenance of the mucosal integrity through the endogenous defense mechanism (Piper, D.W., et al1986). Henna prevented the mucosal lesions induced by pylorus ligation. This suggests that the components present in the extract must be suppressing gastric damage. Henna was also found to decrease the acid volume, total acidity and free acidity. These effects of henna treatment on the parameters that influence the initiation and induction of ulceration may be considered as high desirable property of anti-ulcerogenic agent. In this study our investigations continued with stress induced model

Ulcers induced by stresses in rats, which was protected by our extract. With stress-induced model too, it was the chloroform extract of the henna leaves that offered maximum protection of 54.92% against the ulcer observed (Table 2). It has been reported that stress induced gastric lesions develop as a result of multifunctional impairment of mucosal defense system (Guth, P. H1972) vagal nerve which increases gastric secretion]. (Kitgawa, H et al 1979) and gastric mobility(Garrick, T., et al 1986) Apart from peripheral events, central mechanism including over acidity have also been considered for the pathogenesis of stress ulcers (Henke, P.G et al 1992 Bhatnagar, Met al2005). Based on results of this study it could be suggested that inhibition of acid hyper secretion might be involved in the protection afforded by henna extract in this model.

Table 1: Effect of Ipomoea aquatica Forsk leaves on gastric ulcers induced by pylorus ligation

Group No.	Treatment	Volume of Gastric juice (ml)	Free acidity (m/Eg/1)100g	Total acidity (m/Eg/1)100g	Ulcer index Mean±SEM	%Protection ulcer
I	Control	9.25±0.125	20.65±0.540	56.6±3.410	2.5±0.288	------
II	Ranitidine	3.625±0.118	5.825±0.731	14.8±0.641	0.75±0.144	70.0
III	Aqueous extract	5.675±0.330	10.120±0.149	24.77±0.902	1.62±0.314	35.2
IV	Chloroform Extract	4.375±0.242	7.875±0.253	19.025±0.187	1.12±0.124	55.2
V	Ethanol extract	6.750±0.866	19.27±0.261	44.12±4.364	2.50±0.288	00.0

Table 2: Effect of Ipomoea aquatica Forsk leaves on gastric ulcer induced by stress

Group No.	Treatment	Ulcer Index Mean±SEM	% Protection from ulcer
I	Control	12.5±2.254	----------
II	Ranitidine	1.5±0.144***	87.98
III	Aqueous extract	7.5±0.763*	39.90
IV	Chloroform Extract	5.5±0.288**	54.92
V	Ethanol extract	8.5±0.72	31.92

Table 3: Effects of Ipomoea aquatica Forsk leaves on gastric ulcers induced by aspirin

Group No.	Treatment	Ulcer Index Mean±SEM	% Protection from ulcer
I	Control	12.5±2.254	----------
II	Ranitidine	2.5±0.279**	79.17
III	Aqueous extract	4.0±0.166*	66.60
IV	Chloroform Extract	2.5±0.166**	79.17
V	Ethanol extract	7.5±0.500	37.50

Values are expressed at * P < 0.05; ** P< 0.01; *** P< 0.001-significant reduction in ulcer index as compared with control group, Ns- indicates non significant

Further it has been postulated that histamine might be involved in the formation of pylorus ligated ulcers and plays a mediating a role in gastric secretions stimulated by gastrin vagal excitation (Glicket al, 1966, Rangachari, 1975). Endogenous histamine formation and the release from mast cells in the gastric mucosa have also been implicated in the pathogenesis of gastric ulcers produced by stress Thus, the effects of henna extract on gastric lesion induced by the above two models could be due to the histamine inhibition.

The efficacy of henna extract against gastric ulcers led us to perform yet another model i.e. aspirin induced. This model too resulted in a significant percentage protection (79.17) against gastric ulcers. The percentage protection observed was very much the same as that of standard drug ranitidine (Table3). A few reports have been implicated focal mucosal ischemia as a major event in the development of aspirin induced acute erosive gastritis (Ashley, S. Wet al 198 4, Robins, P. G 1980).

Phoyto chemical screening of Ipomoea aquatica forsk extract (chloroform) revealed presence of contains several vitamins, including A, B, C, E, and “U” (S-methylmethionine), and is used to treat gastric and intestinal disorders aliphatic pyrrolidine amides, carotenoids, hentriacontane, ßsitosteroland its glycosides, prostaglandin, leukotrine, N-trans- and N-cis feruloyl tyramines (Roi, J 1955, . Watt, G.1972, Westphal, E. 1993, Bruemmer, J.H et al 1979, Chen, B.H. et al 1992,. Snyder, G.H et al 1981, Sundar Rao, K et al 1990, Tofern, B., P et al 1999, Van Valkenburg, J.L.C.H et al 2000, . Wills, R.B.H. et al 1996). It has been demonstrated that many drugs or formulations possess potent antioxidant actions and are effective in healing experimentally induced gastric ulcers. Batra and Balraman 2005 have reported that the anti ulcer effect of peptic was due to its antioxidants mechanism of action. We have not carried out studies pertaining to the anti-oxidant nature of our extract however the presence of above compounds can be considered as one of the bioactive responsible for the effects presented in this investigation.

CONCLUSION:

This study reveals significant anti ulcer effects of aqueous, chloroform and ethanol extracts from Ipomoea aquatica Forsk leaves in experimental models of gastric lesions induced by pylorus ligation, aspirin and stress. Further studies using more specific methods are required to explore the chemical compounds responsible for the activity and the mechanism of this activity which might prove important and improved therapies for the treatment and prevention of ulcers.

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