Antidiarrhoeal activity of hot water extract of black tea (Camellia sinensis)

The effect of a hot water extract of black tea (Camellia sinensis (L.) O. Kuntze, Theaceae) on upper gastrointestinal transit and on diarrhoea was investigated employing conventional rodent models of diarrhoea. Black tea extract was found to possess antidiarrhoeal activity in all the models of diarrhoea used. Naloxone (0.5 mg/kg i.p.) significantly inhibited the antidiarrhoeal activity of the extract as well as loperamide, thus indicating a role of the opioid system in the antidiarrhoeal activity of the extract.     

Evaluation of the antidiarrhoeal activity of the hydroethanolic leaf extract of Pupalia lappacea Linn. Juss. (Amaranthaceae)

Ethnopharmacological Relevance

Pupalia lappacea is a medicinal plant found in savannah and woodland localities and forest path sides from Senegal to Southern Nigeria. It has been used in the management of diarrhoea in Nigerian traditional medicine. This study was designed to evaluate the antidiarrhoeal activity of the hydroethanolic leaf extract of Pupalia lappacea (PL).

Materials and methods

The antidiarrhoeal activity of PL was evaluated using the normal and castor oil-induced intestinal transit, castor oil-induced diarrhoea, gastric emptying and intestinal fluid accumulation tests in rodents.

Results

PL (100–400 mg/kg, p.o.) produced a significant dose-dependent decrease in normal and castor oil-induced intestinal transit compared with the control group (distilled water 10 ml/kg, p.o.). This effect was significantly (P<0.05) inhibited by pilocarpine (1 mg/kg, s.c.) but not by yohimbine (10 mg/kg, s.c.), prazosin (1 mg/kg, s.c.), or propranolol (1 mg/kg, i.p.). The extract produced a dose-dependent and significant increase in the onset of diarrhoea. PL (100–400 mg/kg) also reduced the diarrhoea score, number and weight of wet stools. The in-vivo antidiarrhoeal index (ADI_{in vivo}) of 56.95% produced by the extract at the dose of 400 mg/kg was lower compared to that produced by loperamide 5 mg/kg (77.75%). However, PL (400 mg/kg) significantly increased gastric emptying in rats but significantly reduced the volume of intestinal content in the intestinal fluid accumulation test. Phytochemical analysis of the extract revealed the presence of alkaloids, saponins, and fixed oils and fats. The acute toxicity studies revealed that the extract is relatively safe when given orally; no death was recorded at a dose of 10 g/kg.

Conclusion

Results showed that the hydroethanolic leaf extract of Pupalia lappacea possesses antidiarrhoeal activity possibly mediated by antimuscarinic receptor activity.     

Antidiarrhoeal activity of Hypoxis hemerocallidea Fisch. & C. A. Mey. (Hypoxidaceae) Corm (‘African potato’) aqueous extract in rodents

This study investigated the antidiarrhoeal activity of Hypoxis hemerocallidea corm aqueous extract (APE) on experimentally‐induced diarrhoea, gastrointestinal motility, intestinal transit and enteropooling in rodents. H. hemerocallidea corm aqueous extract (APE, 50–400 mg/kg, p.o.) produced dose‐dependent and significant (p < 0.05–0.01) protection of rats and mice against castor oil‐induced diarrhoea, inhibited intestinal transit and delayed gastric emptying. Like atropine (1 mg/kg, p.o.), APE (50–400 mg/kg, p.o.) produced dose‐dependent and significant (p < 0.05–0.01) antimotility effect, and caused dose‐related inhibition of castor oil‐induced enteropooling in the animals. Like loperamide (10 mg/kg, p.o.), APE (50–400 mg/kg, p.o.) dose‐dependently and significantly (p < 0.05–0.01) delayed the onset of castor oil‐induced diarrhoea, decreased the frequency of defaecation and reduced the severity of diarrhoea in the rodents. Compared with control animals, APE (50–400 mg/kg, p.o.) dose‐dependently and significantly (p < 0.05–0.01) decreased the volume of castor oil‐induced intestinal fluid secretion, and reduced the number, weight and wetness of faecal droppings. APE (50–400 mg/mL) also produced concentration‐related and significant (p < 0.05–0.01) inhibitions of the spontaneous, pendular contractions of the rabbit isolated duodenum, and attenuated acetylcholine (ACh, 0.1–5.0 µg/mL)‐induced contractions of the guinea‐pig isolated ileum. Although the precise mechanism of the antidiarrhoeal activity of APE could not be established, the results of this study indicate that APE possesses antidiarrhoeal activity. This finding supports the use of ‘African potato’ as a natural supplementary remedy for the treatment, management and/or control of diarrhoea in some rural communities of southern Africa. Copyright © 2009 John Wiley & Sons, Ltd.     

Evaluation of the antidiarrhoeal activity of Byrsocarpus coccineus

Based on its use in traditional African medicine, the antidiarrhoeal activity of the aqueous leaf extract of Byrsocarpus coccineus, Connaraceae, was evaluated on normal and castor oil-induced intestinal transit, castor oil-induced diarrhoea, enteropooling and gastric emptying. The extract (50, 100, 200 and 400 mg/kg, p.o.) produced a significant (P<0.05) dose dependent decrease in propulsion in the castor oil-induced intestinal transit in mice. The mean peristaltic index (%) for these doses of extract, control (distilled water; 10 ml/kg, p.o.) and morphine (10 mg/kg, s.c.) were 55.27+/-1.86, 53.12+/-3.73, 38.60+/-3.79, 30.25+/-1.27, 89.33+/-5.62 and 20.29+/-3.38, respectively. The effect of the extract at the highest dose was significantly (P<0.05) lower than that of the standard drug. This effect was antagonised by yohimbine (1 mg/kg, s.c.) but not by isosorbide dinitrate (IDN, 150 mg/kg, p.o.). At 200 mg/kg, the extract produced a significant decrease in propulsion in normal intestinal transit. In a dose dependent manner, it delayed the onset of diarrhoea, produced a significant decrease in the frequency of defaecation, severity of diarrhoea and protected the mice treated with castor oil. Mean diarrhoea scores were 30.83+/-1.72, 22.40+/-1.71, 21.43+/-1.32, 13.80+/-0.33, 18.00+/-3.94 and 7.67+/-2.41 for control, extract (50, 100, 200 and 400 mg/kg) and morphine, respectively. This effect was not antagonized by IDN. The extract (400 mg/kg) significantly decreased the volume (ml) of intestinal fluid secretion induced by castor oil (0.60+/-0.23) compared with 1.27+/-0.12 for control. However, there was no significant effect on gastric emptying. The results obtained suggest that Byrsocarpus coccineus possesses antidiarrhoeal activity due to its inhibitory effect on gastrointestinal propulsion, mediated through alpha(2) adrenoceptors, and also inhibition of fluid secretion. Preliminary phytochemical analysis revealed the presence of alkaloids, tannins, saponins, reducing sugars, glycosides and anthraquinones.     

The antidiarrhoeal activity of Alchornea cordifolia leaf extract

Diarrhoea is a public health problem in developing countries. It is therefore important and useful to identify plants with antidiarrhoeal activity. Alchornea cordifolia is quoted by many traditional healers as a plant with this activity. The antidiarrhoeal activity of its leaf extract was investigated against castor oil induced diarrhoea in mice, using morphine as the standard reference drug. A significant (p < 0.01) dose related (100 mg/kg, 200 mg/kg, 400 mg/kg, 800 mg/kg) antidiarrhoeal activity of A. cordifolia leaf ethanol extract was observed with 800 mg/kg extract being the most effective. It delayed mouse intestinal transit accelerated by castor oil, inhibited the production of diarrhoeal faeces and modified the fluid and electrolyte transport across the colonic mucosa when administered intraluminally. Phytochemical screening revealed the presence of tannins and flavonoids which may account for the increased colonic water and electrolyte reabsorption, a mechanism suggested for the antidiarrhoeal activity of A. cordifolia.     

Evaluation of the antidiarrhoeal effect of Sanseviera liberica Gerome & Labroy (Agavaceae) root extract

Ethnopharmacological relevance

The aqueous root extract of Sansevieraliberica (Agavaceae), SL, is used in Traditional African Medicine (TAM) for the treatment of diarrhoea. However, the scientific basis for this usage has not been established.

Aim of the study

To evaluate the antidiarrhoeal activity of SL using various pharmacological models.

Materials and methods

The intestinal transit, castor oil induced diarrhoea, enteropooling, and gastric emptying methods were used in this study.

Results

SL (25–400 mg/kg, p.o.) produced significant (P < 0.05) dose dependent reduction in propulsive movement in both the normal and castor oil induced intestinal transit tests in mice. Peak effect was elicited at 200 mg/kg but this effect was lower than that produced by morphine (10 mg/kg, s.c.). The effect of SL on castor oil induced intestinal transit was antagonized by isosorbide dinitrate, IDN (150 mg/kg, p.o.) but not by yohimbine (1 mg/kg, s.c.). In the castor oil induced diarrhoea test, SL significantly delayed the onset and decreased the frequency and severity of diarrhoea. The effect at 200 mg/kg was comparable to that of morphine and was reversed by IDN. SL at the dose of 200 mg/kg significantly reduced the volume of intestinal secretion induced by castor oil but produced no effect on gastric emptying.The extract was practically nontoxic administered p.o. The LD₅₀ was 631 mg/kg given i.p. Phytochemical analysis revealed the presence of oils, reducing sugars, alkaloids, saponins, anthraquinones, and tannins in the extract.

Conclusion

The results obtained in this study suggest that the aqueous root extract of Sanseviera liberica possesses antidiarrhoeal property due to inhibition of gastrointestinal propulsion and fluid secretion, possibly mediated through inhibition of the nitric oxide pathway. This justifies the use of the plant extract in TAM for the treatment of diarrhoea.     

Antidiarrhoeal activity of the ethanol extract of Paederia foetida Linn. (Rubiaceae)

Paederia foetida L. is used as a remedy for diarrhoea and dysentery in Asia, but has not been investigated for its antidiarrhoeal properties. Antidiarrhoeal activity of 90% ethanol extract of Paederia foetida was investigated in this study using castor oil and magnesium sulphate-induced diarrhoea models in mice. The extract significantly increased the latent period of diarrhoea in both the models. In the castor oil study, the purging index (PI) value lowered in 1 h of the study at (100, 250 and 500 mg/kg) doses. The effect continued up to 6-h period only at 500 mg/kg dose. The plant notably reduced the purging index value in a dose-dependent manner in magnesium sulphate-induced diarrhoea. Paederia foetida, in general, reduced the gastrointestinal motility with barium sulphate milk both in 15- and 30-min time intervals. The extract significantly decreased the cisplatin-induced gastrointestinal motility at all doses at both time intervals. The extract also enhanced the morphine-induced reduction of motility at 500 mg/kg dose level at both time intervals. The results suggest that Paederia foetida showed antidiarrhoeal activity by inhibiting intestinal motility and justify its use in traditional medicine.     

Assessment of antidiarrhoeal activity of the methanol extract of Xylocarpus granatum bark in mice model

The methanol extract of Xylocarpus granatum bark was studied for its antidiarrhoeal properties in experimental diarrhoea, induced by castor oil and magnesium sulphate in mice. At the doses of 250 and 500 mg/kg per oral, the methanol extract showed significant and dose-dependent antidiarrhoeal activity in both models. The extracts also significantly reduced the intestinal transit in charcoal meal test when compared to atropine sulphate (5 mg/kg; i.m.). The results showed that the extracts of Xylocarpus granatum bark have a significant antidiarrhoeal activity and supports its traditional uses in herbal medicine.     

Antidiarrhoeal activity of the ethyl acetate extract of Baphia nitida (Papilionaceae)

In our search for plants useful in the treatment of diarrhoea, we investigated the ethyl acetate extract of Baphia nitida (BN) using intestinal transit, enteropooling and gastric emptying tests in mice and rats. In the castor oil intestinal transit test, BN produced a significant (P<0.05) dose dependent decrease in propulsion with peristaltic index (PI) values of 56.85+/-6.76, 36.84+/-3.04 and 31.98+/-2.60%, respectively at doses of 100, 200 and 400mg/kg vs. 89.33+/-6.28% for control. The effect at 400mg/kg was significantly lower than that of morphine, 10mg/kg, s.c. (20.29+/-3.78%), and was antagonized by isosorbide dinitrate, IDN (150mg/kg, p.o.) but not by yohimbine (1mg/kg, s.c.). This effect was not potentiated by atropine (1mg/kg, s.c.). In the castor oil-induced diarrhoea test, BN produced a significant increase in onset of diarrhoea (103.40+/-8.74, 138.80+/-17.04 and 174.8+/-29.04min, 100 to 400mg/kg, vs. 47.60+/-8.76min for control and 226.10+/-12.57min for morphine). The severity of diarrhoea (diarrhoea score) was dose dependently reduced (19.00+/-2.26, 17.04+/-1.89, 15.00+/-2.05, 100 to 400mg/kg, vs. 31.40+/-2.11 for control and 7.7+/-2.2 for morphine). This effect was not antagonized by IDN or yohimbine. The effect on severity was, however, potentiated by atropine. BN also reduced the number and weight of wet stools but did not have any significant effect on intestinal fluid accumulation and gastric emptying. Results obtained suggest that the ethyl acetate extract of Baphia nitida is endowed with antidiarrhoeal activity possibly mediated by interference with the l-arginine nitric oxide pathway and synergistic with antagonistic action on muscarinic receptors.     

Antidiarrhoeal and antimicrobial activities of Emilia coccinea (Sims) G. Don extracts

Emilia coccinea (Sims) G. Don is reported to possess a number of medicinal properties including antidiarrhoeal and antimicrobial activities. The antidiarrhoeal effects of both methanol and aqueous extracts of the leaves of Emilia coccinea were studied in rats against castor oil-induced diarrhoea at the doses of 200, 400 and 600 mg/kg body weight. The methanol extract, and to a lesser extent the aqueous extract, significantly prolonged the time for diarrhoeal induction; it reduced the frequency of diarrhoea episodes and decreased the propulsion of charcoal meal through the gastrointestinal tract in a dose dependent manner. The aqueous extract did not have any antimicrobial activity at the tested concentration (5 mg/ml), but the methanol extract was most active on Escherichia coli. These results may support the fact that this plant is used traditionally to cure diarrhoea.     

Antidiarrhoeal activity of Geranium incanum Burm. f. (Geraniaceae) leaf aqueous extract in mice

Ethnopharmacological relevance

Geranium incanum Burm. f. (Geraniaceae) is used in South Africa especially in rural communities by traditional medicine practitioners to treat diarrhoea. However, scientific evidence does not exist in any literature to corroborate the claim of therapeutic success of the plant species in diarrhoea.

Aim of study

The study intended to investigate the antidiarrhoeal activity of the leaf aqueous extract of Geranium incanum in mice.

Materials and Methods

Castor oil induced diarrhoeal test was used to assess the antidiarrhoeal activity of Geranium incanum. Gastrointestinal tract transit of charcoal meal test was used to assess the antipropulsive activity of the plant extract while the acute toxicity study and phytochemical analysis were carried out using well established protocols and methods.

Results

The antidiarrhoeal activity of Geranium incanum was investigated by studying the effect of leaf aqueous extract of the plant species on castor oil-induced diarrhoea in mice. The leaf aqueous extract of Geranium incanum significantly reduced faecal output in castor oil -induced diarrhoea and also significantly reduced the number of diarrhoeal episodes. Geranium incanum significantly delayed the onset of diarrhoea induced by castor oil and significantly reduced the number of animals exhibiting diarrhoea. Loperamide, a standard antidiarrhoeal drug, produced similar effects to the leaf aqueous extract of Geranium incanum on castor oil-induced diarrhoea. Both Geranium incanum and loperamide significantly reduced the intestinal propulsion of charcoal meal in mice. The phytochemical analysis of the leaves revealed the presence of tannins, saponins particularly steroidal saponin, and flavonoids. The LD₅₀ of the plant species obtained was greater than 4000 mg/kg (p.o.).

Conclusion

The data obtained indicate that the leaf aqueous extract of Geranium incanum has both antidiarrhoeal and antipropulsive activities The data also show that the plant material given orally may be safe and/or non toxic in mice. However, further investigation on the acute toxicity and on the mechanism of the antidiarrhoeal effect of the plant species needs to be carried out.     

Antitumour property and toxicity of Barringtonia racemosa Roxb seed extract in mice

Ethnomedical survey has shown that the seeds of Barringtonia racemosa Roxb are traditionally used in certain remote villages of Kerala (India) to treat cancer like diseases. So the seed extracts were tested for their antitumour activity and toxicity. Intraperitoneal (i.p.) daily administration of 50% methanol extract of this seed to mice challenged with 1 million Dalton's Lymphoma Ascitic (DLA) cells resulted in remarkable dose dependent anti-DLA activity in mice. The optimum dose was found to be 6 mg/kg. This dose protected all the animals challenged with the tumour cells. The efficacy of the drug was found to be better than that of a standard drug, vincristine in this tumour model. However, the oral administration showed only marginal activity compared to i.p. administration. The extract was found to be devoid of conspicuous acute and short-term toxicity to mice, when administered daily, (i.p.) for 14 days up to a dose of 12 mg/kg (which was double the concentration of optimum therapeutic dose). The treated mice showed conspicuous toxic symptoms only at 24 mg/kg. The LD(50) to male mice for a single i.p. dose was found to be 36 mg/kg. The seed extract is an attractive material for further studies leading to drug development.     

Evaluation of antidiarrhoeal profile of Jussiaea suffruticosa linn. extract in rats

The antidiarrhoeal potential of a methanol extract of the aerial parts of Jussiaea suffruticosa Linn. (MEJS) was studied with several experimental models of diarrhoea in rats. MEJS treated rats showed significant inhibitory activity against castor oil induced diarrhoea and PGE(2) induced enteropooling. It also showed a significant reduction in gastrointestinal motility following a charcoal meal in rats. The extract exhibited significant antidiarrhoeal potential at doses of 100,200 and 300 mg/kg in all the animal models and thus established the efficacy of MEJS as a potent antidiarrhoeal agent.     

A pharmacological evaluation of Baphia nitida Lodd (Leguminosae) ethanolic extract on rats and mice

Fresh leaves of Baphia nitida supplied by a herbalist were extracted, screened phytochemically and then subjected to various pharmacological tests. The phytochemical tests showed the presence of saponin, flavonoid glycosides and true tannins. In the dose range used, no acute toxicity was observed for the ethanolic extract. The extract showed a dose dependent antinociceptive (analgesic) activity in mice with the analgesic activity of 500 mg/kg extract being comparable to that of 300 mg/kg of acetylsalicylic acid. The extract demonstrated an antidiarrhoeal effect by protecting rats against castor oil induced diarrhoea. This was also dose related but less than the protection afforded by sodium salicylate. The extract did not demonstrate any appreciable anticonvulsant effect against strychnine-induced convulsion in rats.     

Inhibition of Microlax-induced experimental diarrhoea with narcotic-like extracts of Psidium guajava leaf in rats.

Measurement of rates of propulsion in the small intestine in control and experimental groups of male Sprague-Dawley rats (200-250 g) were carried out as a means of assessing antidiarrhoeal activity of aqueous extracts of the leaf of Psidium guajava (L.), using morphine as the standard drug of reference. Hyperpropulsion (diarrhoea) was induced by gavaging rats in a control group with Microlax, using phenol red mixed into it as a marker in the intestine, and the mean rate of the hyperpropulsion was determined. The normal rate of propulsion, defined as the percentage of the length of the ileum traversed by the front of the dye in 1 h after gavaging animals with a liquid paraffin-phenol red meal, was also determined in another control group. In experimental groups pretreated with enteral administration of either morphine or aqueous extracts, 1 h before the challenge with Microlax, the percentage inhibition to the hyperpropulsive rate (antidiarrhoeal activity) was calculated. Both morphine and the extracts produced a dose-response relationship in their antidiarrhoeal effects. A dose of 0.2 ml/kg fresh leaf extract produced 65% inhibition of propulsion. This dose is equiactive with 0.2 mg/kg of morphine sulphate. The antidiarrhoeal action of the extract may be due, in part, to the inhibition of the increased watery secretions that occur commonly in all acute diarrhoeal diseases and cholera.     

Antidiarrhoeal activity of some Egyptian medicinal plant extracts

The antidiarrhoeal activity of six Egyptian medicinal plant extracts (200 and 400 mg kg(-1)) and their effect on motility of isolated rabbit's duodenum was investigated. Phytochemical screening of the plant extracts for their active constituents was also carried out by TLC. Oral administration of methanol extract from Conyza dioscoridis (CD) or Alhagi maurorum (AM) in a 200 mg kg(-1) dose exhibits a significant antidiarrhoeal effect against castor oil-induced diarrhoea, while Mentha microphylla (MM), Convolvulus arvensis (CA), Conyza linifolia (CL) produced no significant effect. In a dose of 400 mg kg(-1), Mentha microphylla, Conyza dioscoridis, Alhagi maurorum, Zygophyllum album (ZA), and Conyza linifolia produced a significant (P<0.01) effect, while Convolvulus arvensis produced no antidiarrhoeal effect in rats. Methanol extract of Mentha microphylla, Conyza dioscoridis, Zygophyllum album, and Convolvulus arvensis induced a dose-dependent (0.4-2.8 mg ml(-1)) relaxation of rabbit's duodenal smooth muscle. Alhagi maurorum and Conyza linifolia increased the contractile force in concentrations between 0.4 and 1.6 mg ml(-1). Higher concentrations (>3.2 mg ml(-1)) caused a rapid depressant effect. The depressant effect induced by Alhagi maurorum (in a higher dose) and Zygophyllum album appeared to be due to calcium channel blocking effect, since CaCl(2) could not restore the contractile response of the tissue impregnated in calcium free-medium. However, a ganglionic blocking effect appeared to be a possible mechanism of action of Mentha microphylla and Conyza dioscoridis since a stimulant dose of nicotine could not restore the contractile response of the tissue. The effect of Convolvulus arvensis and Conyza linifolia was not through any of the common mediators. Phytochemical screening revealed the presence of tannins, flavonoids, unsaturated sterols/triterpenes, carbohydrates, lactones and proteins/amino acids as major constituents.     

Relationship between the antidiarrhoeal effects of Hange-Shashin-To and its active components.

This study was designed to examine the relationship between the antidiarrhoeal effects of Hange-Shashin-To (TJ-14) and its active components. Oral treatment with TJ-14 at 1000 mg/kg significantly inhibited castor oil-induced diarrhoea. Both the 50% methanol eluate fraction (fraction III) and the methanol eluate fraction (fraction IV) showed antidiarrhoeal effects at oral doses of 68 mg/kg and 63 mg/kg, respectively, corresponding to 1000 mg/kg of TJ-14. TJ-14 (1000 mg/kg, p.o.) showed a significant increase in blood corticosterone levels. Increased blood corticosterone was noted after the oral administration of 63 mg/kg of fraction IV. The inhibitory activity of TJ-14 on cyclooxygenase-2 (COX-2) was also observed in fractions III and IV. The main component of fraction III was Scutellariae Radix-derived baicalin. Fraction IV contained Glycyrrhizae Radix-derived glycyrrhizin and isoliquiritin, Coptidis Rhizoma-derived berberine, coptisine and palmitine. Ginseng Radix-derived saponins were also present in fraction IV. These compounds inhibited castor-oil induced diarrhoea at oral doses of 10 or 30 mg/kg. Thus, the present results indicate that Scutellariae Radix, Glycyrrhizae Radix, Ginseng radix and Coptidis Rhizoma-derived components are involved in the antidiarrhoeal action of TJ-14.     

Antidiarrhoeal activity of the methanol extract of the barks of Xylocarpus moluccensis in castor oil- and magnesium sulphate-induced diarrhoea models in mice

The methanol (MeOH) extract of the barks of Xylocarpus moluccensis, and different fractions of this extract were studied for antidiarrhoeal activity using castor oil- and magnesium sulphate-induced diarrhoea models in mice. At the doses of 250 and 500 mg/kg, the MeOH extract showed significant antidiarrhoeal activity in both models. The EtOAc fraction (EAF) and the residual MeOH fraction (RMF) exhibited similar activity using a dose of 250 mg/kg in both models. No antidiarrhoeal activity was observed with the chloroform fraction (CHF) at the test doses. When tested for antibacterial effect, the MeOH extract displayed moderate inhibitory activity against Escherichia coli, Vibrio cholera, Staphylococcus aureus, Staphylococcus epidermis, Shigella dysentery, Staphylococcus pyogenes, Salmonella typhi, Pseudomonas aeruginosa and Enterobacter aerogenes. While the CHF inhibited the growth of Escherichia coli, Vibrio cholerae, Shigella dysenteriae, Shigella sonnei, Staphylococcus epidermis, Staphylococcus pyogenes and Pseudomonas aeruginosa, the EAF was active against all test organisms except Vibrio cholera and Staphylococcus epidermis. The RMF inhibited the growth of all the test organisms with moderate zone of inhibition. On the basis of these findings, it can be assumed that Xylocarpus moluccensis could be a potential source for novel 'lead' discovery for antidiarrhoeal drug development.     

Preliminary pharmacological screening of Bixa orellana L. leaves

Preliminary pharmacological studies were performed on the methanol extract of Bixa orellana L. (Bixaceae) leaves to investigate neuropharmacological, anticonvulsant, analgesic, antidiarrhoeal activity and effect on gastrointestinal motility. All studies were conducted in mice using doses of 125, 250 and 500 mg/kg of body weight. In the pentobarbitone-induced hypnosis test, the extract statistically reduced the time for the onset of sleep at 500 mg/kg dose and (dose-dependently) increased the total sleeping time at 250 and 500 mg/kg dose. A statistically significant decrease in locomotor activity was observed at all doses in the open-field and hole-cross tests. In the strychnine-induced anticonvulsant test, the extract increased the average survival time of the test animals (statistically significant at 250 and 500 mg/kg). The extract significantly and dose-dependently reduced the writhing reflex in the acetic acid-induced writhing test. Antidiarrhoeal activity was supported by a statistically significant decrease in the total number of stools (including wet stools) in castor oil-induced diarrhoea model. A statistically significant delay in the passage of charcoal meal was observed at 500 mg/kg in the gastrointestinal motility test. The extract was further evaluated in vitro for antioxidant and antibacterial activity. It revealed radical scavenging properties in the DPPH assay (IC(50)=22.36 microg/ml) and antibacterial activity against selected causative agents of diarrhoea and dysentery, including Shigella dysenteriae.     

Evaluation of some medicinal plant extracts for antidiarrhoeal activity

The antidiarrhoeal effect of seven plant extracts namely: the aerial parts of Euphorbia paralias L. (EP), Bidens bipinnata L. (BB), Cynachum acutum L. (CyAc), Diplotaxis acris (Forssk.) Boiss (DA), Convolvulus fatmensis (CF) and Schouwia thebaica Webb (ST) and the leaves of Plantago major L. (PM), was evaluated on castor oil-induced diarrhoea, gastrointestinal movement in rats (charcoal meal) and on the motility of duodenum isolated from freshly slaughtered rabbits. A significant antidiarrhoeal effect of the tested plant extracts against castor oil-induced diarrhoea in rats was achieved by 200 and 400 mg/kg. The tested plant extracts decreased the gastrointestinal movement as indicated by the significantly (p<0.05 to 0.001) decreased distance travelled by the charcoal meal. The large dose of the tested plant extracts was slightly more effective than the small one. The antidiarrhoeal effect was confirmed by the reported dose dependent inhibition of the motility of duodenum isolated from freshly slaughtered rabbits. The EP and PM methanol extract produced a transient stimulation followed by inhibition in doses of less than 0.05 and 1.6 mg/kg, respectively. Higher concentrations caused rapid muscle relaxation. Tannins, flavonoids, unsaturated sterols/triterpenes, carbohydrates, lactones and proteins/amino acids were reported as major active constituents of the tested plants.