Screening model of anti-diarrheal activity-sA

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Screening model of anti-diarrheal activity Prensented by :- SAGAR PATNI (P’CHEMISTRY) M.PHARMA (AIBS KANPUR):

Screening model of anti-diarrheal activity Prensented by :- SAGAR PATNI (P’CHEMISTRY) M.PHARMA (AIBS KANPUR)


Diarrhea Diarrhea is characterized by increased frequency of bowel movement, wet stool and abdominal pain.

Diarrhea (cont'd):

Diarrhea (cont'd) Acute diarrhea Sudden onset in a previously healthy person Lasts from 3 days to 2 weeks Self-limiting Resolves without sequelae Chronic diarrhea Lasts for more than 3 weeks Associated with recurring passage of diarrheal stools, fever, loss of appetite, nausea, vomiting, weight loss, and chronic weakness

Causes of Diarrhea:

Causes of Diarrhea Acute Diarrhea Bacterial Viral Drug induced Nutritional Protozoal Chronic Diarrhea Tumors Diabetes Addison’s disease Hyperthyroidism Irritable bowel syndrome

Antidiarrheals: Mechanism of Action:

Antidiarrheals : Mechanism of Action Adsorbents Coat the walls of the GI tract Bind to the causative bacteria or toxin, which is then eliminated through the stool Examples: bismuth subsalicylate (Pepto-Bismol), kaolin-pectin, activated charcoal, attapulgite ( Kaopectate ) Anticholinergics Decrease intestinal muscle tone and peristalsis of GI tract Result: slowing the movement of fecal matter through the GI tract Examples: belladonna alkaloids ( Donnatal ), atropine

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Intestinal flora modifiers Bacterial cultures of Lactobacillus organisms work by: Supplying missing bacteria to the GI tract Suppressing the growth of diarrhea-causing bacteria Example: L. acidophilus ( Lactinex ) Opiates Decrease bowel motility and relieve rectal spasms Decrease transit time through the bowel, allowing more time for water and electrolytes to be absorbed Examples: paregoric, opium tincture, codeine, loperamide (Imodium), diphenoxylate ( Lomotil )

Screening model:

Screening model In vivo model Castor oil-induced diarrhea Gastrointestinal motility test Castor oil-induced enter pooling

Rationale ,Purpose & Methods :

Rationale , P urpose & Methods Rationale: The induction of diarrhea with castor oil results from the action of ricinoleic acid formed by hydrolysis of the oil. Ricinoleic acid produces changes in the transport of water and electrolytes resulting in a hypersecretory response.In addition to hypersecretion , ricinoleic acid sensitizes the intramural neurons of the gut.

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Purpose: The seeds of Swietenia macrophylla are used in traditional medicine for the treatment of diarrhoea . Thus the petroleum ether extract of Swietenia macrophylla ( Meliaceae ) seeds was investigated for its anti- diarrhoeal property in Wister albino rats to substantiate folklore claim . Methods: Petroleum ether extract of the seeds of this plant, at graded doses (25, 50 & 100mg/kg body weight ) was investigated for anti- diarrhoeal activity in term of reduction in the rate of defecation and consistency of faeces in castor oil induced diarrhoea . To understand the mechanism of its antidiarrhoeal activity , its effect was further evaluated on intestinal transit and castor oil nduced intestinal fluid accumulation ( enteropooling ).

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Animals Swiss albino rats (150 – 180 g) of either sex were selected for the experiments. Animals were allowed to be acclimatise for a period of 2 weeks in our laboratory environment prior to the study. Animals were housed in polypropylene cages ( 4 animals per cage), maintained under standard laboratory conditions (i.e. 12:12 hour light and dark sequence; at an ambient temperature of 25±2ºC ; 35-60% humidity); the animals were fed with standard rat pellet diet and water ad libitum .

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Chemicals and Reagents Atropine sulphate and diphenoxylate ( standard reference antidiarrhoeal drugs), castor oil (laxative agent), normal saline solution ( 0.9% NaCl ), charcoal meal (10% activated charcoal in 5 % gum acacia) and vehicle (2%v/v Tween 80 in distilled water) were used .

Castor oil-induced diarrhoea:

Castor oil-induced diarrhoea Rats were fasted for 18 h and divided into five groups of six animals per group. Castor oil at a dose of 1 ml/animal orally, was given to all groups of animals for the induction of diarrhoea . Thirty minutes after castor oil administration, the first group (control group) received vehicle (0.5% v/v Tween 80 in distilled water),

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while the second, third and fourth groups were given petroleum ether extract at doses of 25, 50 and 100 mg/kg body weight respectively by oral route. The fifth group received the reference drug, diphenoxylate (50 mg/kg body weight) Animals of all groups were placed separately in individual cages lined with filter paper.


Contd. The filter papers were changed every hour and the severity of diarrhoea was assessed hourly for six hours. The total number of faeces excreted and the total weight of faeces were recorded within a period of six hour and compared with the control group.

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The total number of diarrhoeal faeces of the control group was considered 100%. The results were expressed as percentage of inhibition of diarrhoea .

Gastrointestinal motility test:

Gastrointestinal motility test This experiment was done by using charcoal meal as a diet marker 12. The rats were divided into five groups of six animals each and fasted for eighteen hours before the experiment. The first group (the control group) was orally administered the vehicle (0.5% Tween 80 in distilled water).

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The second, third and fourth groups orally received petroleum ether extract at doses of 25, 50 and 100 mg/kg body weight respectively. The fifth group received the standard drug, atropine sulphate (0.1 mg/kg body weight intraperitoneal ). Thirty minutes later each animal was given 1 ml of charcoal meal (10% activated charcoal in 5% gum acacia) orally.


Contd. Each animal was sacrificed thirty minutes after administration of charcoal meal. The distance covered by the charcoal meal in the intestine was expressed as a percentage of the total distance traveled from the pylorus to the caecum .

Castor oil-induced enteropooling:

Castor oil-induced enteropooling Intraluminal fluid accumulation was determined by the method of Boominathan et al. 2005. Over night fasted rats were divided into five groups ofsix animals each . Contd.

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Group 1 which received normal saline (2 ml/kg intraperitoneal ) served as the control group. Group 2 received atropine (3 mg/kg intraperitoneal ) and groups 3, 4 and 5 received extract of 25, 50 and 100mg/kg intraperitonealy , respectively, one hour before the oral administration of castor oil (1 ml). Two hours later, the rats were sacrificed;


CONTD . the small intestine was removed after tying the ends with threads and weighed. The intestinal content was collected by milking into a graduated cylinder and their volume was measured. The intestine was reweighed and the difference between the full and empty was calculated.

Statistical analysis:

Statistical analysis Data were analyzed by one-way ANOVA followed by Dunnett’s t-test usin computerized GraphPad InStat version 3.05 (Graph Pad software , U.S.A .).


EVALUATION With anti-diarrheal agents dose-response curves are obtained for decrease of hyper-secretion (stool weight) and for increase of the diarrhea-free period are obtained . Inhibitors of prostaglandin biosynthesis increase the diarrhea free period but do not affect early diarrheal secretion . Contd ….


MODIFICATIONS OF THE METHOD Inhibition of castor oil-induced diarrhea in mice was tested by Bianchi and Goi (1977). Dajani et al. (1977) tested antidiarrheal activity in castor-oil treated monkeys . Mannitol -induced diarrhea was used as model in calves ( Fioramonti and Buéno 1977) and in pigs.

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