Antidiarrhoeal Activity Of The Methanolic Extract Of The Leaves Of Paullina Pinnata Linn (Sapindaceae)
I Osarenmwinda, J Omonkhelin, D Ejiro
Citation
I Osarenmwinda, J Omonkhelin, D Ejiro. Antidiarrhoeal Activity Of The Methanolic Extract Of The Leaves Of Paullina Pinnata Linn (Sapindaceae). The Internet Journal of Health. 2008 Volume 9 Number 1.
Abstract
Various parts of the plant
The Research work was done in the Faculty of Pharmacy, University of Benin, Benin City Nigeria.
Introduction
Diarrhoea is increased fluidity, frequency or volume of bowel movements. It may be acute or chronic. Diarrhoea can be very serious in infants and elderly people because of the risk of severe, potentially fatal dehydration1. Diarrhoea occurs worldwide and causes 4% of all deaths and 5% of health loss to disability. Diarrhoea, a very common symptom of HIV/AIDS affects 90% of PLWHA and results in significant morbidity and mortality. In Africa, diarrhoea is four times more common among children with HIV and seven times more common among adults with HIV than their HIV-negative household members2.
In the past 2 decades, there has been a search for drugs that might inhibit the process of diarrhoea development especially the secretory process. Although a number of drugs have emerged, none has found a place in the routine management of diarrhoea3.
Local herbalists have depended on medicinal plants as a reliable means of treating diarrhoea. Hence the use of medicinal plants that possess anti-diarrhoeal activities has been explored as a measure that could be of benefit in combating widespread diarrhoea infections especially in third world countries4.
Numerous studies have validated the traditional use of antidiarrhoeal medicinal plants by investigating the biological activity of extracts of such plants, which have antispasmodic effects, delay intestinal transit, suppress gut motility, stimulate water absorption or reduce electrolyte secretion5.
Of the numerous phytochemicals (such as alkaloids, tannins, flavonoids and terpenes) present in active extracts, tannins and flavonoids are thought to be responsible for antidiarrhoeal activity by increasing colonic water and electrolyte reabsorption. Others act by inhibiting intestinal motility6.
As some of the active ingredients are potentially toxic, there is a need to evaluate the safety of plant preparations. A few clinical trials have evaluated the safety and tolerability of traditional and herbal medicine preparations used to treat diarrhoea and generally indicate that minimal side effects are observed. However, with increased popularity of plant derived medicines in Western Society, the benefits and potential dangers of these medicines must be considered7.
Materials And Method
Plant Material
Fresh leaves of
Animals
Swiss Albino mice weighing between 20-30g of either sex were obtained from the Physiology Department of the University of Ibadan, Ibadan, Oyo State, Nigeria. The animals were maintained in a 12 hour light and dark cycle and had access to feed (grower’s marsh) and water
The animals were allowed to acclimatize for 14 days before being subjected to experimental protocol.
Methods
Plant Extraction
The powdered plant material (300g) was macerated in 1.5 litres methanol for 72 hours. The mixture was stirred at 6 hourly intervals using a glass stirrer. The extract was filtered and evaporated to near dryness using a rotary evaporator. The concentrated extract was weighed, stored in an air-tight container, labelled and refrigerated at 4°C prior to use.
The stock solution was extemporaneously prepared using distilled water to a concentration of 100mg/ml for administration to the experimental animals.All reagents used were of analytical grades.
Phytochemical Screening
Qualitative tests for the presence of plant secondary metabolites such as carbohydrates, reducing sugars, Saponins, tannins and alkaloids were carried out using standard procedures 8.
Pharmacological Screening
Two models were employed in evaluating the antidiarrhoeal activity.
a. Small intestinal transit time in mice
Adult mice of both sexes weighing between 20-30g were divided into five groups of four mice each. Group A which was the control group received normal saline intraperitoneally at a dose of 10ml/kg. Group B, C and D received 50mg/kg, 100mg/kg and 200mg/kg of the extract respectively intraperitoneally; while Group E received Atropine 0.2mg/kg also intraperitoneally. 30 minutes after administration, charcoal meal was administered using an Orogastric tube at a dose of 0.2mls/mouse. 30 minutes after the administration of the charcoal meal, each animal was placed under chloroform anaesthesia and then sacrificed by cervical dislocation. The mice were dissected and the stomach and small intestines removed and stretched out on a clean surface. The distance travelled by the charcoal meal from the stomach in relation to the total length of the intestine was measured. Thereafter values were expressed as a percentage and the percentage inhibition calculated.
b. Inhibition of Castor Oil-Induced Diarrhoea
Mice were divided into 5 groups of four animals each. Group A (control) received 10ml/kg normal saline intraperitoneally, Groups B, C and D received 50mg/kg, 100mg/kg and 200mg/kg of the extract respectively intraperitoneally also. While Group E received 0.2mg/kg Atropine intraperitoneally.
After 30 minutes, all the mice in each group received 0.2mls castor oil orally. The mice were then placed in separate cages lined with filter paper. The following parameters were observed over the next 4 hours:
i. The time elapsed between the administration of castor oil (cathartic agent) and the excretion of the first diarrhoeic stool
ii. The total number of both wet and dry diarrhoea droppings (this was counted every 30 minutes for 4 hours)
iii. The total weight of both the wet and dry diarrhoeal stool in this period of time (by weighing the filter paper before and after the experiment).
Acute Toxicity
Mice (16) were randomly selected into 4 groups of 4 mice each. The animals were starved for 12 hours prior to testing. Groups A,B,C and D were orally administered with 0.5g, 1g, 2g and 4g of the methanolic leaf extract of
General symptoms of toxicity like jerks and writhes were observed over 24 hours and up to 5 days.
Statistical Analysis
The data were compared using one way analysis of variance (ANOVA) and Tukey Kramer multiple comparison test. Graph pad instat version 2.05 software (UK). All data were expressed as mean ± SEM (standard error of mean).
Results and Discussions
Phytochemical analysis
Table 3.1: The qualitative analysis of the leaves of
The result of the phytochemical screening of the leaves of
Pharmacological Screening
Table 3.2: Inhibitory effects of the methanolic extract of the leaves of
Values are expressed as mean of percentages travelled by the charcoal meal in relation to the full small intestinal length±SEM (n=4/group).
Level of significance: P value is 0.0002 which is very significant.
Table 3.3: Antidiarrhoeal activity of the extract and atropine on castor oil-induced diarrhoea in mice.
Figure 1: Effect of methanolic extract of
The induction of diarrhoea by castor oil is attributed to its active ingredient ricinoleic acid9 which stimulates the production of several mediator substances that include prostaglandins, nitric oxide, and platelet activating factor, cAMP and tachykinins10.
The induction of diarrhoea by castor oil can also be attributed to the liberation of prostaglandins by colonic cells11. Inhibitors of prostaglandin synthesis such as ibuprofen and aspirin can reduce significantly, the release of prostaglandins and the volume of fluid loss induces by castor oil12. Since the extract was capable of inhibiting the castor oil induced diarrhoea,
The effect of the methanolic extract of
The extract, besides producing an antisecretory effect, was found to inhibit the intestinal transit in mice providing 79.34% inhibition at 200mg/kg dose.
In this model, it was observed that the extract at 50mg/kg, 100mg/kg and 200mg/kg, significantly (p > 0.05, p < 0.01 and p < 0.001) inhibited the transit of charcoal meal along the intestine by 37.06%, 59.81% and 79.34% respectively. This was compared to the control group, and standard (Atropine 0.2mg/kg) group which caused 56.91% inhibition. The effect of the extract at 100mg/kg is as or more potent than Atropine and at 200mg/kg the inhibition produced is 22% more than that produced by Atropine.
Although there was no investigation into the mechanism of action of the extract, this reduction in percentage distance travelled can be used to establish the intestinal smooth muscle relaxation and antisecretory effect of the extract, this smooth muscle relaxation may be responsible for the use of the plant ethnomedically in treatment of menstrual cramps and in preventing miscarriages in pregnant women.
Acute Toxicity
The extract was well tolerated by the animals as no sign of acute toxicity like restlessness, dizziness or seizures were observed over a 24 hour period and even up to 5 days. There were no deaths after the administration of 0.5g/kg, 1g/kg, 2g/kg and 4g/kg of the methanolic extract of
Conclusion
This work has demonstrated that the Methanolic extract of the leaves of Paullina pinnata has anti diarrhoea activity comparable to those of Atropine and hence may be potentially useful in the management of diarrhoea and could serve as a lead to new antidiarrhoea agents in humans, a validation of its traditional use in the treatment of diarrhoea in traditional medicine.
Correspondence to
Patrick Igbinaduwa, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Benin, Benin City. Phone: +2348037422420 Email: pigbinaduwa@yahoo.com
