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.     

Antiprotozoal screening and cytotoxicity of extracts and fractions from the leaves,stem bark and root bark of Alstonia congensis

Ethnopharmacological relevance

To evaluate the antiprotozoal activity and cytotoxicity of extracts and fractions from the leaves, root bark and stem bark of Alstonia congensis (Apocynaceae), used in traditional medicine against parasitic diseases.

Materials and methods

The aqueous and 80% MeOH extracts, and a series of fractions and subfractions from the leaves, stem and root bark of Alstonia congensis were tested in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, Trypanosoma cruzi, Lesihamania infantum and the chloroquine and pyrimethamine-resistant K1 strain of Plasmodium falciparum. Their cytotoxicity on MRC-5 cells (human lung fibroblasts) was evaluated as well.

Results

The aqueous and 80% MeOH extracts and a series of subfractions of each plant part exhibited pronounced antiprotozoal activity against the K1 strain of Plasmodium falciparum with IC₅₀ values ranging from 2 to 5 µg/ml, and good activity against Trypanosoma brucei brucei and Trypanosoma cruzi with IC₅₀ values ranging between 5 and 10 µg/ml. The residual 80% MeOH extract from the leaves, and the total alkaloid extract from stem and root bark were the only subfractions active against Leishmania infantum with IC₅₀ values <10 µg/ml. None of the samples from the root bark was cytotoxic against MRC-cell lines (CC₅₀>64 µg/ml). In general, the aqueous extract (traditional decoction) showed the highest selectivity, especially against Plasmodium falciparum.

Conclusion

These results can partly support and justify the traditional use of these plant parts of Alstonina congensis as raw materials for the preparation of traditional remedies to treat parasitic diseases such as malaria and trypanosomiasis.     

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 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.     

Anti-diarrhoea and analgesic activities of the methanol extract and its fractions of Jasminum amplexicaule Buch.-Ham. (Oleaceae)

Jasminum amplexicaule Buch.-Ham. (Oleaceae) has been commonly used in the traditional medicine in dysentery, diarrhoea and bellyache in China. In the present work, the methanol extract of Jasminum amplexicaule and different fractions of this extract were studied for anti-diarrhoea and analgesic activities. The anti-diarrhoea activities were investigated using castor oil-induced, magnesium sulphate-induced diarrhoea models, antienteropooling assay and gastrointestinal motility models in mice. The analgesic activities were studied using hot-plate, writhing and formalin models in mice. At the doses of 100, 200 and 400mg/kg, the methanol extract (ME) showed significant and dose-dependent anti-diarrhoea and analgesic activity in these models. The chloroform fraction (CHF), ethyl acetate fraction (EAF) and the residual methanol fraction (RMF) exhibited similar activity using a dose of 200mg/kg in these models. The pharmacological activities of the n-butanol fraction (BUF) were lesser than the ME extract and other fractions. These results may support the fact that this plant is traditionally used to cure diarrhoea and pain.     

Anti-ulcerogenic properties of the aqueous and methanol extracts from the leaves of Solanum torvum Swartz (Solanaceae) in rats

ETHNOPHARMACOLOGICAL RELEVANCE: Solanum torvum (Solanaceae) is a plant currently used in Cameroon ethnomedicine for the treatment of stomach ailments. AIM OF THE STUDY: The present study was undertaken to determine the anti-ulcer potential of the aqueous and methanol extracts from the leaves of Solanum torvum. MATERIALS AND METHODS: The aqueous and methanol extracts from the leaves of Solanum torvum were tested orally at the doses of 250, 500 and 750mg/kg, on gastric ulcerations experimentally induced by HCl/ethanol, indomethacin, pylorus ligation and stress. The fractionation of the methanol extract through silica gel column chromatography produced seven different fractions (A-G) which were tested orally at the dose of 100mg/kg against HCl/ethanol-induced ulceration. RESULTS: The methanol extract at the dose of 750mg/kg produced 98.12, 99.16, 98.70 and 96.03% inhibition when gastric ulcerations were induced by HCl/ethanol, indomethacin, pylorus ligation and stress, respectively. The aqueous extract at the same dose produced 96.55, 96.86, 98.63 and 98.63% inhibition on ulcerations induced respectively by HCl/ethanol, indomethacin, pylorus ligation and stress. All the fractions of the methanol extract significantly inhibited ulcer formation. Fraction F which contains flavonoids and triterpens was the most active and exhibited an inhibitory percentage of 84.74. Both extracts significantly increased mucus production and reduced gastric acid secretion. CONCLUSIONS: The aqueous and methanol extracts of the leaves of Solanum turvum possess anti-ulcerogenic properties that may be due to cytoprotective mechanism. These results support the ethnomedical uses of the plant in the treatment of gastric ulcer.     

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.     

Antidiarrheal activity of Pyrenacantha staudtii Engl. (Icacinaceae) aqueous leaf extract in rodents

Ethnopharmacological relervance

Pyrenacantha staudtii Engl. (Icacinaceae) is a plant which is traditionally used for the treatment of blemnorrhea, hernia, insomnia, intestinal pain and diarrhea in Nigeria. Therefore the core aim of the present study is to evaluate antidiarrheal activity of Pyrenacantha staudtii aqueous extract (PSE).

Materials and methods

The antidiarrheal activity was evaluated using castor oil-induced diarrhea method. The effects of Pyrenacantha staudtii aqueous extract on gastrointestinal motility, intestinal transit and enteropooling were also examined in rodents. The acute toxicity effect of the aqueous extract of Pyrenacantha staudtii was also investigated.

Results

Pyrenacantha staudtii aqueous extract (PSE, 100-400 mg/kg, p.o.) produced dose-dependent and significant (P < 0.05-0.01) protection of rats and mice against castor oil-induced diarrhea, inhibited intestinal transit, and delayed gastric emptying. PSE, produced dose-dependent and significant (P < 0.05-0.01) antimotility effect, caused dose-related inhibition of castor-oil-induced enteropooling in animals, comparable to atropine (1 mg/kg, p.o.). Like loperamide (10 mg/kg, p.o.), PSE, dose-dependently and significantly (P < 0.05-0.01) delayed the onset of castor-oil induced diarrhea, decreased the frequency of defecation, and reduced the severity of diarrhea in the rodents. Compared with control animals, PSE, 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 fecal droppings.

Conclusion

The findings of this study indicate that PSE possesses antidiarrheal property in rats and mice. These findings confirm the ethnomedicinal use of Pyrenacantha staudtii leaf as a valuable natural remedy for the treatment, management and/or control of diarrhea.     

Toxicological evaluation of the hydroethanol extract of Tabernaemontana crassa (Apocynaceae) stem bark

Aim

Tabernaemontana crassa Benth. is a medicinal plant widely used in Cameroon folk medicine to treat a variety of affections. This study was aimed at evaluating its toxicological profile.

Materials and methods

The 70% (v/v) hydroethanol (HE) extract from the stem bark of this plant was given to albino Wistar rats by oral gavage to study the acute and sub-acute toxicities.

Results

The results of histopathological studies revealed that there was a dose-related effect in liver, lungs and kidneys and that there was no difference in tissue profile of control group and those receiving 6 weeks daily treatment of 0.5 g/kg b.w. The result of the acute toxicity indicated the medium lethal dose (LD50) of 6.75 g/kg body weight (b.w.) after 48 h of treatment and the significant variation (P < 0.05) of the relative body weight, serum alkaline phosphatase (ALP), alanine aminotransferase (ALT), total bilirubin (TBil), direct bilirubin (DBil) and creatinine (SCr) at the dose of 6 g/kg b.w. These results also indicated significant variation of the liver alkaline phosphatase, aspartate aminotransferase (AST), ALT, total proteins (TP), glutathione (GSH) and malondialdehyde (MDA) and renal creatinine (RCr) and urea (RU) at 6 g/kg b.w. The result of the sub-acute toxicity showed significant changes in the body weight but no modification (P > 0.05) of blood and liver indices for the animal taking 6 weeks daily doses of the HE compared to the control group.

Conclusions

The results showed that this extract was fairly non-toxic but that consumption of higher doses up to 6 g/kg b.w. could cause organ injuries. Moderated consumption of small doses up to 0.5 g/kg b.w. daily for 6 weeks appeared to be safe.     

Hypoglycemic and hypolipidemic effects of the aqueous fresh leaves extract of Clerodendrum capitatum in Wistar rats

Diabetes mellitus, the most common endocrine disorder of carbohydrate metabolism, is treated in the African traditional phytotherapies with the cold water decoction of Clerodendrum capitatum (CC). In the current study, the hypoglycemic and hypolipidemic effects of fresh leaves aqueous extract of CC were studied in four groups of six adult Wistar rats per group and weighting 120-150 g, by administering graded oral doses (100, 400 and 800 mg/kg/day) of the extract for 14 days. On the 15th day, the fasted rats were anesthetized under inhaled halothane and blood samples obtained through cardiac puncture. Phytochemical analysis of CC extract was conducted using standard procedures while the preliminary acute oral toxicity study was also conducted using limit dose test of Up and Down Procedure at a limit dose of 5000 mg/kg body weight/oral route. Results of the study showed CC to cause significant (p<0.05, p<0.001) dose dependent hypoglycemic and hypolipidemic effects but had no effect on the pattern of weight gain in the treated rats. Although no lethal effect was recorded with CC oral administration for up to 5000 mg/kg body weight/oral route, but there was an associated transient somatomotor and behavioral toxicities. Phytochemical results revealed the presence of saponins, flavonoids, alkaloids, tannin, glycosides and reducing sugars in the extract. Thus, the folkloric use of Clerodendrum capitatum in the treatment of suspected type 2 diabetics has a positive correlation with scientific data generated in this study.     

Antimicrobial activity of the methanolic extract, fractions and four flavonoids from the twigs of Dorstenia angusticornis Engl. (Moraceae)

The methanolic extract (DAT), fractions (FRS) and four flavonoids, namely Gancaonin Q (1), Stipulin (2), Angusticornin B (3) and Bartericin A (4), isolated from the twigs of Dorstenia angusticornis (Moraceae), were tested for their in vitro antimicrobial activity. A total of 22 microbial cultures belonging to three Candida species, 6 Gram-positive and 13 Gram-negative bacterial species were used in this study. The inhibition zones (IZ) of the test samples against the pathogens were determined by the Agar Hole Diffusion test while the Liquid dilution method was used to determine their minimal inhibition concentrations (MIC) and their minimal microbicidal concentrations (MMC). Results indicate that DAT, compounds 3 and 4 inhibited the growth of all test pathogens. DAT, FRS 3-6, compounds 3 and 4 were both antibacterial and anticandidal. A single-dose oral toxicity performed in accordance with the OPPTS 870.1100 and OECD 401guideline showed that DAT was not toxic. Our findings provide a possible basis for the potential use of twigs from Dorstenia angusticornis in the treatment of infectious diseases.     

Anti-angiogenic activity of the methanol extract and its fractions of Ulmus davidiana var. japonica

This study aimed to elucidate anti-angiogenic activity of Ulmus davidiana var. japonica that has been widely used in folk medicine. The methanol extract (UDE) of Ulmus davidiana var. japonica concentration-dependently displayed a strong inhibition in the chick chorioallantoic membrane (CAM) angiogenesis. The n-butanol fraction of UDE and subsequent 30% MeOH subfraction were identified to be most responsible for the anti-angiogenic activity.     

Evaluation of diuretic activity of Amaranthus spinosus Linn. aqueous extract in Wistar rats

Ethnopharmacological relevance

Traditional Siddha medicine literature claims that the Amaranthus spinosus Linn. (family: Amaranthaceae) whole plant possesses diuretic property.

Aim of the study

To evaluate the diuretic potential of Amaranthus spinosus aqueous extract (ASAE) in rats.

Material and methods

Different concentrations of ASAE (200, 500, 1000, 1500 mg/kg), thiazide (10 mg/kg) and vehicle were orally administered to rats (n = 6 animals per group) and their urine output was collected after 24 h. Volume, pH, Na⁺, K⁺ and Cl⁻ concentrations of urine were estimated.

Results

ASAE produced increase in Na⁺, K⁺, Cl⁻ excretion, caused alkalinization of urine, showed strong saluretic activity and carbonic anhydrase inhibition activity. These effects were observed predominantly at 500 mg/kg dose and there was no dose–response relationship.

Conclusion

Our study strongly suggests that the Amaranthus spinosus is acting as a thiazide like diuretic with carbonic anhydrase inhibitory activity which restates the claim as diuretic herb in Siddha medicine.     

Anti-inflammatory effect of extract and fractions from the leaves of Byrsonima intermedia A. Juss. in rats

Aim of the study

Byrsonima intermedia is commonly used for its antiseptic, antimicrobial, and anti-inflammatory properties in the treatment of diarrhea and dysentery in Brazilian folk medicine. The purpose of this study was to examine the anti-inflammatory activity of the aqueous extract and fractions of Byrsonima intermedia leaves.

Materials and methods

Rats with carrageenan-induced paw edema and fibrovascular tissue growth, which was induced by subcutaneous implantation of a cotton pellet, were used as acute and chronic animal models of inflammation to investigate the anti-inflammatory effects of the aqueous extract and the individual ethyl acetate (EtOAc) and aqueous fractions of Byrsonima intermedia and catechin. High-performance liquid chromatography (HPLC) was used to determine the fingerprint chromatogram of the aqueous extract and fractions of Byrsonima intermedia.

Results

The crude aqueous extract at test doses of 30-300 mg/kg p.o. clearly demonstrated anti-inflammatory effects by reducing carrageenan-induced paw edema, as did the ethyl acetate (100 mg/kg) and aqueous fractions (30-100 mg/kg). In the chronic inflammation rat animal model with fibrovascular tissue growth, the aqueous extract of Byrsonima intermedia (BiAE) at doses of 30-300 mg/kg and the individual EtOAc and aqueous fractions at doses of 30-100 mg/kg and catechin significantly reduced the formation of granulomatous tissue. The presence of catechin and phenolic compounds in the extract and fractions of Byrsonima intermedia was confirmed using HPLC.

Conclusion

BiAE and the individual EtOAc and aqueous fractions of Byrsonima intermedia exhibited chronic and acute anti-inflammatory efficacy in rats, which supports previous claims of its use in traditional medicine.     

Induction of insulin secretion by an aqueous extract of Tabernanhte iboga Baill. (Apocynaceae) in rat pancreatic islets of Langerhans

The effect of an aqueous extract of Tabernanthe iboga (TBEt) was studied in the rat islets insulin secretion based on its use in traditional medicine for the treatment of diabetes. Rats islets were isolated by collagenase digestion. In insulin release experiments, the insulin content was determined by Enzyme-Link Immunosorbent Assay (ELISA). For experiments on ⁴⁵Ca²⁺ Uptake, the radioactive content was determined using a liquid scintillation analyzer. The extract (10⁻³ μg/ml-100 μg/ml) did not exert a significant increase of insulin secretion (p > 0.05) in the presence of 2.8 mM of glucose (a none stimulatory concentration). Whereas, in the presence of 11.1 mM of glucose (stimulatory concentration), TBEt augmented glucose-stimulated insulin secretion in a dose-dependent manner. Interestingly, the secretory effect of the extract was glucose-dependent (5.6-16.7 mM). Furthermore, the insulinotropic effect of TBEt (1 μg/ml) was significantly potentiated (p < 0.001) in K⁺-depolarised media as well as in the presence of 2.8 mM and 16.8 mM of glucose concentrations. In contrast, in the same conditions, TBEt failed to stimulate the high K⁺ medium-induced insulin release. The extract significantly amplified (p < 0.001 and p < 0.05) the insulin secretion induced by either IBMX or tolbutamide. Diazoxide, cobalt or calcium removal inhibited the insulinotropic effect of the extract. TBEt increased glucose-induced ⁴⁵Ca²⁺ uptake in rat islets. Overall, our findings suggest that Tabernanthe iboga contains water soluble insulinotropic compounds. The insulin secretion of TBEt's active principles might involve the closure of K⁺-ATP and the intensification of calcium influx through voltage-sensitive Ca²⁺ channels.     

Anti-inflammatory activity of the extract, fractions and amides from the leaves of Piper ovatum Vahl (Piperaceae)

Leaves of Piper ovatum are known in folk medicine as “joão burandi” or “anestésica” and in traditional Brazilian medicine are used to treat inflammatory disease. The hydroalcoholic extract, fractions, and a mixture of piperovatine (1) and piperlonguminine (2) in a proportion of 2:3 obtained from Piper ovatum were assayed for anti-inflammatory activity by means of carrageenan-induced pleurisy in rats and croton oil-induced ear edema in mice. The hydroalcoholic extract was analyzed by high-performance liquid chromatography. Fraction constituents were evaluated by phytochemical screening, and the mixture of amides (1 and 2) was identified by analyses of spectral data of ¹H and ¹³C nuclear magnetic resonance. Acute toxicity of the extract also was evaluated. At 500 mg/kg, the hydroalcoholic extract of Piper ovatum leaves did not reduce the volume of inflammatory pleural exudates compared with control animals. However, the hydroalcoholic extract and fractions F1–F3 at doses of 5.0 mg/ear and a mixture of piperovatine (1) and piperlonguminine (2) at doses of 2.5, 1.25, and 0.625 mg/ear significantly reduced the degree of ear edema. Taken together, the results indicate that the amide fractions piperovatine and piperlonguminine showed the greatest inhibitory activity of topical inflammation induced by croton oil.     

Acute toxicity, antinociceptive activity and indole alkaloids of aqueous extract from bark of Aspidosperma cuspa (Kunth) Blake

Etnopharmacological relevance

Aspidosperma cuspa (Kunth) Blake (Apocynaceae) is popularly known as “amargosa” or “cuspa”, and its bark is used in folk medicine primarily for pain.

Aim of the study

In the present study the acute toxicity, antinociceptive effect and alkaloids of the aqueous decoction extract of the Aspidosperma cuspa bark in mice was investigated.

Materials and methods

Acute toxicity was tested using a variation of the method described by Lichfield and Wilcoxon. The antinociceptive activity was evaluated using the acetic acid induced writhing and tail-flick tests. The phytochemical analysis was performed.

Results and conclusion

Oral administration of the extract did not cause animal death (LD₅₀>4 g/kg), and the histological analysis showed an absence of alterations in all organs examined. TD₅₀ of the extract was 0.5521 g/kg for male mice and 1.1565 g/kg for females. The aqueous extract at doses 276 mg/kg (p.o.) did not produce a significant inhibition of acetic acid-induced writhes, but showed a significant effect in tail-flick test. Naloxone, an opioid receptor antagonist, pretreatment inhibited significantly the antinociceptive activity of the extract. It is suggested that the aqueous decoction extract of the bark of Aspidosperma cuspa has an antinociceptive effect, and this may be mediated by opioid receptors. Three indole alkaloids (aspidocarpine, 11-methoxytubotaiwine and picraline) were isolated from the aqueous extract. The antinociceptive activity of the extract is presumed to be due to these compounds.     

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.     

Toxicological evaluation of the aqueous leaf extract of Moringa oleifera Lam. (Moringaceae)

Ethnopharmacological relevance

The rapid increase in consumption of herbal remedies worldwide has been stimulated by several factors, including the notion that all herbal products are safe and effective. However, over the past decade, several news-catching episodes in developed communities indicated adverse effects, sometimes life-threatening, allegedly arising as a consequence to taking herbal products or traditional medicines from various ethnic groups. Despite the popular use of Moringa oleifera for treating various disorders, there is limited or no scientific data available regarding safety aspects of this remedy, nor are there any documented toxicological studies that can be used to ascertain the safety index of its herbal preparation. Therefore, this present study aimed to carry out extensive toxicological evaluation of the aqueous leaf extract of Moringa oleifera.

Materials and Methods

In an acute toxicity test, male Wistar albino mice were orally administered an aqueous extract up to 6400 mg/kg and intraperitoneally up to 2000 mg/kg. A sub-chronic toxicity test was performed by daily administration with the extract at 250, 500 and 1500 mg/kg orally for 60 days. Control rats received distilled water. Sperm quality was analyzed, haematological and biochemical (liver enzymes, urea and creatinine) parameters were determined and a histopathological examination was carried out.

Results

The LD₅₀ was estimated to be 1585 mg/kg. The extract did not elicit any significant difference (P ≥ 0.05) in sperm quality, haematological and biochemical parameters in the treated rats compared to the control. Moreover, there was no significant difference in weight gain of the control and treated animals although there was a dose-dependent reduction in food consumption of the animals treated with 250 to 1500 mg/kg extract.

Conclusions

Results obtained in this study suggest that the aqueous leaf extract of Moringa oleifera is relatively safe when administered orally.     

Teratogenic effects, acute and sub chronic toxicity of the leaf aqueous extract of Ocimum suave Wild (Lamiaceae) in rats

The aqueous extract from the leaves of Ocimum suave was evaluated for acute and sub chronic toxicity and teratogenic effects. Swiss mice were administered single oral doses of 2000, 4000, 6000 and 8000 mg/kg and monitored for death and body weight gained for 7 days (acute toxicity). In sub-acute toxicity, experimental rats, received daily doses of 250, 500 and 1000 mg/kg for 42 consecutive days and the toxic effects were assessed using biochemical and haematological data and histology of vital organs. In a teratogenic study, 1-day pregnant rats were administered orally 500 and 1000 mg/kg of extract daily for 21 consecutive days and 14th day corpora lutea and foetal implants and litter size at birth were noted. Reproductive performance of F(1) generation rats was studied by crossing them at maturity and recording the number, birth weight and physical presentation of the young offspring. Acute intake of extract up to 8000 mg/kg did not produce mortality or significant changes in general behaviour. Sub chronic treatment did not show any change in body and organ weights, feeding habits or behaviour between the control and the treated groups of both sexes. Haematological analysis and blood biochemistry revealed no toxicity effects of the extract. No gross abnormalities or histological changes were observed. Teratogenic and fertility studies did not reveal any toxic manifestations or foetal abnormalities. The leaf aqueous extract of Ocimum suave is non toxic in acute and sub chronic intake.