Collection of Plant material
The plants selected for present work A. conchigera (Family: Zingiberaceae) and Plumbago indica L. (Family: Plumbaginaceae) were collected from Naramuk, Rajsthali of Rangamati district. After collection, suitable herbarium sheet for each plant with some general information were prepared and send to Bangladesh Council of Scientific and Industrial Research (BCSIR), Baluchara, Chittagong for identification. They provided us the scientific name of the plants.
Extraction:
The collected plant (leaves and stems) was separated from undesirable materials or plants or plant parts and was shed-dried (35-50°c). The plant was ground into a coarse powder with the help of a suitable grinder. The powder was stored in an airtight container and kept in a cool, dark and dry place until extraction commenced. About 75 gm of powdered plant material of Plumbago indica L. (Family: Plumbaginaceae) was taken in a clean, flat bottomed amber glass container and soaked in 350 ml of methanol. The container with its contents was sealed and kept for a period of 10 days accompanied by continuous shaking. The whole mixture then underwent a coarse filtration by a piece of clean, white cotton materials. Then they were filtered by using Whatman filter paper number 1 and the solvent was made to evaporate under the room temperature. On the other hand, About 185 gm of powdered plant material of A. conchigera (Family: Zingiberaceae) was subjected with 1700ml of methanol in a Soxhlet Apparatus. The obtained extract was collected and made to evaporate the solvent bellow 50°c temperature. The residues were stored in a refrigerator until further studies.
Animals:
Young Swiss-albino mice of either sex, average weight 18-25 gm of either sex were employed in the experiment taking four in a group. The mice were purchased from the Animal Research Branch of the Bangladesh Council of Scientific and Industrial Research (BCSIR), Chittagong, Bangladesh. The mice were kept separately in wooded cages having dimension of (15 x 10 x 8) inch. Soft wood shavings were placed in the cages for housing of the mice. The room where the mice were housed was well ventilated for air and light. Husk and excreta were removed from the cages on every day. Fresh water and pellets of mice foods were given to the mice regularly. The mice were kept at least one week in the laboratory to get them adapted with the environment before being employed in any experiment.
Determination of Antidiarrhoeal Activity:
The Antidiarrhoeal Activity was determined according to the method described by Shoba and Thomas, 2001 10 follows for this study. The animals were all screened initially by giving 0.3 ml of castor oil and only those showing diarrhoea are selected for the final experiment. The animals were divided into control, positive control and test groups containing five mice in each group. Control group received vehicle (1% Tween-80 in water) at a dose of 10 ml/kg body weight orally. The positive control group receives loperamide at the dose of 3 mg/kg orally; test group received the ethanol extract at the doses of 250 and 500mg/kg body weight orally. Each animal was placed in an individual cage, the floor of which was lined with blotting paper. The floor lining was changed every hour. Diarrhoea is induced by oral administration of 0.3 ml castor oil to each mouse, 30 minutes after the above treatments11. During an observation period of 240 min, the total number of faecal output and the number of diarrheic faeces excrete by the animals is recorded. A numerical score based on stool consistency is assigned as follows: normal stool =1 and watery stool = 2.
Castor Oil Induced Diarrhoea:
Upon oral administration, castor oil mixes with bile and pancreatic enzymes and liberates ricinoleic acid from the tryglyceride. A small amount of ricinoleic acid is absorbed from the gastrointestinal tract and metabolized like any other fatty acid but most remains in the intestine where it produces its antiabsorptive or secretory effect. The ricinoleic acid thus liberated readily forms ricinoleate salts with sodium and potassium in the lumen of the intestine. The ricinoleate salt formed as such behaves like a soap or surfactant within the gut and at the mucosal surface. The precise mechanism of how ricinoleate salts induce diarrhoea is not yet to be known. But most agreed view is that it stimulates the intestinal epithelial cell’s adenyl cyclase, release prostaglandins and especially prostaglandins of the E series along with serotonin (5-HT) have been termed as ‘diarrhoeagenic hormones’.
Statistical Analysis:
All the values of antidiarrheal, tests were expressed as mean + SEM (Standard error of the Mean). Statistical differences between the mean of the various groups were analyzed by using Students “t” test12. Probability (p) value of 0.05 or 0.01 was considered as significant. All the graphical presentation and statistical calculations were preparing“Microsoft Excel-2000”.