Anti-diarrhoeal and ulcer-protective effects of the aqueous root extract of Guiera senegalensis in rodents

The anti-diarrhoeal and ulcer-protective properties of the aqueous root extract of Guiera senegalensis, a popular herbal traditional medicine in Nigeria were investigated in rats and mice. Acute toxicity studies were also carried out. The intestinal transit in mice was significantly (P < 0.05) reduced and gastric emptying delayed. One hundred and Two hundred milligrams per kilogram (p.o.) of the extract elicited a greater anti-motility activity than 0.1 mg/kg of atropine. The extract exhibited ulcer-protective properties against ethanol-induced ulceration in rats with maximal anti-ulcer activity recorded at 100 mg/kg. Guiera senegalensis also exerted significant anti-enteropooling effects causing a dose-related inhibitory effect on castor oil-induced enteropooling in rats. A profound anti-diarrhoeal activity was observed when Guiera senegalensis was tested in diarrhoeic mice. The frequency of defaecation as well as the wetness of the faecal droppings was significantly reduced. Furthermore, the extract produced 100% inhibition of castor oil-induced diarrhoea in mice. The oral LD50 values obtained were > 5000 mg/kg in both mice and rats. The results support the folkloric applications of Guiera senegalensis for the treatment of diarrhoea and ulcer in Nigerian herbal traditional medicine.

Neuropharmacological effects of the aqueous extract of Nauclea latifolia root bark in rats and mice

The present study evaluated the neuropharmacological effects of the aqueous extract of Nauclea latifolia root bark in rodents. Effects on the spontaneous motor activity (SMA), exploratory behaviour, pentobarbital sleeping time, apomorphine-induced stereotypic behaviour and motor coordination (rota-rod performance) were investigated. The extract (50-200 mg/kg p.o.) significantly (P<0.05) decreased the SMA and exploratory behaviour in mice and prolonged pentobarbital sleeping time in rats dose-dependently. The extract also remarkably attenuated the intensity of apomorphine-induced stereotypy dose-dependently in mice, but had no effect on motor coordination as determined by the performance on rota-rod. These results indicate the presence of psychoactive substances in the aqueous extract of the root bark of Nauclea latifolia.

Effect of aqueous leaf extract of Irvingia gabonensis on gastrointestinal tract in rodents

Effect of the aqueous leaf extract of I. gabonensis on the gastrointestinal tract was investigated on isolated rabbit jejunum, guinea pig ileum, gastrointestinal motility, castor oil-induced diarrhoea in mice and castor oil-induced fluid accumulation in rats. The results showed that the extract exhibited a concentration-dependent relaxation of spontaneous pendular movement of isolated rabbit jejunum and guinea pig ileum, and attenuated both acetylcholine-induced contraction of rabbit jejunum and histamine-induced contraction of guinea pig ileum. The extract (100, 200 and 400 mg/kg) also caused a significant dose-dependent decrease of gastrointestinal motility in mice (40.12, 39.45 and 37.45%), intestinal fluid accumulation in rats (71.43, 81.63 and 83.27%), and remarkably protected mice against castor oil-induced diarrhoea [58.33, 75 and 91.67% (Di Carlo score)] respectively. Preliminary phytochemical screening of the aqueous leaf extract of I. gabonensis revealed the presence of saponins, tannins, phenols and phlobatanins.

Effect of the aqueous extract of Chrysanthellum indicum on calcium mobilization and activation of rat portal vein

The effects of the aqueous extract of Chrysanthellum indicum (CI) on calcium activation and mobilization were studied using the rat portal vein. The extract caused a concentration-dependent contraction of the portal vein. KCl (80 mM), norepinephrine (NA, 10(-6)M) and CI (4 mg/ml) evoked sustained contraction of the portal vein. In Ca-free medium (with EGTA) the contractions evoked by these agents were reduced significantly. The times-to-peak of KCl, NA and CI were similar -in normal PSS, but in Ca-free medium the times-to-peak for KCl and CI were greatly increased. The contractions induced by CI were not inhibited by chlorpropamide and prazosin, but were blocked by verapamil. The data obtained suggest that the aqueous extract of CI utilizes extracellular calcium pools to bring about contractile response and this effect might be mediated through the activation of potential-sensitive channels.

Smooth muscle contraction induced by Indigofera dendroides leaf extracts may involve calcium mobilization via potential sensitive channels

The contractile effects of the aqueous extract of the leaves of Indigofera dendroides (ID) were studied on the gastrointestinal motility in mice and isolated smooth muscle preparations obtained from rats and guinea pigs. The contractile effects of 10(-6) M acetylcholine, 80 mM KCl and 1.6 mg/ml ID were measured on the rat ileal smooth muscle exposed to calcium-free buffer or physiological solution, to determine the calcium pools mobilized by extract for activation of contraction. Acute toxicity test (LD(50)) was also carried out in mice. The result showed that ID (0.05-3.2 mg/ml) produced a concentration-dependent contraction of the guinea pig and rat ileum. These responses were not blocked by mepyramine (2.49 x 10(-9) M), verapamil (8.14 x 10(-9) M), or pirenzepine (4.7 x 10(-7) M), but were blocked completely by atropine (2.92 x 10(-9) M). A significant increase in propulsion of gastrointestinal motility was observed. Acetylcholine, KCl and ID produced contractions in Ca(2+) free media. The phasic components of the contractile responses to Ach as well as the tonic component of K(+) and ID-induced contractions were relatively resistant to short periods of calcium-free exposure. Ach, K(+) and ID still caused contractions in the presence of verapamil. The data revealed that ID-induced contractions were not mediated by histaminergic receptors, calcium channels, M1 muscarinic receptors. It also suggests that Ach mobilize Ca from some tightly bound or intracellular pool, whereas high K(+) and ID may mobilize Ca from some superficial or loosely-bound pool.

Evaluation of the antidiarrhoeal effects of Zizyphus spina-christi stem bark in rats

The antidiarrhoeal effects of the methanol extract of Zizyphus spina-christi stem bark were evaluated in laboratory rodents. Studies on castor oil induced diarrhoea, intraluminal fluid accumulation, and gastrointestinal transit time were carried out. Results obtained revealed that the extract caused a dose dependent protection of rats against castor oil induced diarrhoea, decreased the intraluminal fluid accumulation and gastrointestinal transit. The intraperitoneal and oral LD(50) values were found to be 346+/-5.6 and 1200+/-41.2 mg/kg in mice. Preliminary phytochemical screening revealed the presence of glycosides, resins, saponins, and tannins. It is suggested that the extract may contain biologically active components that may be useful against diarrhoea, thereby justifying its use in ethnomedical practice as an antidiarrhoeal agent.

Central inhibitory activity of the aqueous extract of Crinum giganteum

The aqueous extract of Crinum giganteum given intraperitoneally at doses of 6.25, 12.5 and 25 mg/kg in rats prolonged the duration of pentobarbital sleeping time and in mice reduced spontaneous motor activity, decreased the exploratory activity and attenuated amphetamine-induced stereotype behavior. The intraperitoneal and oral preliminary LD(50) in mice were found to be 627 and 1468 mg/kg, respectively. The data obtained suggest that the aqueous extract of C. giganteum contains some biologically active principles with sedative activity.

Sedative effects of the methanolic leaf extract of Newbouldia laevis in mice and rats

The effect of the methanolic extract of Newbouldia laevis seem on the central nervous system of rats and mice was investigated. The extract was tested on spontaneous motor activity, exploratory behaviour, apomorphine induced climbing behaviour in mice and pentobarbital induced hypnosis in rats. The extract caused considerable reductions of exploratory activity, spontaneous motor activity and prolonged pentobarbitone-induced hypnosis in rats. It was also found to attenuate apomorphine climbing in mice. The results suggest that the methanolic extract of Newbouldia laevis may contain principles that have sedative properties.

Effect of the aqueous extract of African mistletoe, Tapinanthus sessilifolius (P. Beauv) van Tiegh leaf on gastrointestinal muscle activity

Effects of the aqueous extract of T. sessilifolius on the gastrointestinal muscle were investigated on smooth muscle preparations isolated from rabbit jejunum, guinea pig ileum and on gastrointestinal transit in mice. Elemental analysis of the extract was also carried out. The aqueous extract of T. sessilifolius evoked a concentration dependent contraction of the rabbit jejunum and guinea pig ileum. The contractions evoked by the extract were not attenuated either by atropine or mepyramine, but they were completely blocked by verapamil. The elemental analysis revealed the presence of Mg, Zn, Fe, Cu, and very high concentration of Ca. The intraperitoneal LD50 in mice was found to be 1500 mg/kg. The aqueous extract of T. sessilifoliius possesses active components that may be mediating the observed biological activity through calcium mobilization.

Effect of Zizyphus spina-christi Willd aqueous extract on the central nervous system in mice

The effects of the aqueous extract of Zizypus spina-christi Willd root bark against exploratory behaviour, spontaneous motor activity (SMA), motor coordination (Rota-rod performance) and pentobarbital-induced hypnosis were investigated in mice. The extract induced a significant (P<0.05) dose-dependent reduction in exploratory behaviour and SMA when administered orally. It also prolonged pentobarbital sleeping time but failed to inhibit motor coordination (rota-rod performance) in the experimental mice. These results suggest that the extract contained some constituents that depress the central nervous system, which may not be due to neuromuscular blockade.

Anti-inflammatory, analgesic and anti-lymphocytic activities of the aqueous extract of Crinum giganteum

The anti-inflammatory, anti-lymphocytic and analgesic properties of Crinum giganteum, a popular herb used for the management of asthma and other respiratory disorders was investigated in rats and mice. The extract dose-dependently produced significant (P<0.05) inhibition of formalin induced pain in rats. It also demonstrated significant (P<0.01) inhibition of abdominal constriction induced with 0.75% v/v acetic acid in mice. On the cotton pellet induced granulomatous tissue formation in rats, the extract significantly (P<0.05) decreased the weight. However, no significant inhibition was observed in the egg albumin-induced inflammation in rats. Oral administration of this extract in rats for 14 days significantly affected (P<0.05) the total leukocyte count and the overall percentage lymphocytes. The intraperitoneal and per oral LD(50) were 627+/-5.8mg/kg and 1486+/-18.9 mg/kg in mice and 520+/-10.2mg/kg and 1023+/-4.3 mg/kg in rats, respectively. Preliminary phytochemical analysis of the extract indicates the presence of tannins. These results therefore indicate that C. giganteum bulb contains biologically active principles, which have potentials for the treatment of inflammatory processes.

Neuropharmacological effect of the aqueous extract of Sphaeranthus senegalensis in mice

Effects of the aqueous extract of Sphaeranthus senegalensis Vaill. (Family: Compositae) were studied on spontaneous motor activity, exploratory behaviour, rota-rod performance and pentobarbital sleeping time in mice. Preliminary phytochemical evaluation and acute toxicity (LD(50)) values were also studied. The extract (50 and 100 mg/kg p.o.) produced reduction in spontaneous motor activity, exploratory behaviour and motor coordination and prolonged pentobarbital sleeping time. Glycosides, saponins and tannins were shown to be present in the extract. The i.p. LD(50) in mice was 2735.61 and 5000 mg/kg orally. The results suggest that the aqueous extract of S. senegalensis contains some active principles, which may be sedative in nature.

Behavioral effects of the aqueous extract of Guiera senegalensis in mice and rats

Behavioral effects of the aqueous extract of Guiera senegalensis on the central nervous system of mice and rats were investigated. Spontaneous motor activity, pentobarbital sleeping time, amphetamine-stereotyped behavior, exploratory activity and performance on treadmills (rota-rod) were evaluated. The results revealed that the aqueous extract of G. senegalensis reduced spontaneous motor activity in mice, prolonged the duration of pentobarbital sleeping time in rats and attenuated amphetamine-induced stereotype behavior in rats. The extract also decreased exploratory activity in mice and had no observable effects on motor coordination (rota-rod) at the doses tested. The results suggested that the crude aqueous extract of G. senegalensis possesses some biologically active principles that are sedative in nature.

Effect of niprisan on single oral dose pharmacokinetics of paracetamol in rats

The single oral dose pharmacokinetics of paracetamol was studied alone and after coadministration with NIPRISAN In rats. Paracetamol concentrations were measured in rat plasma using UV-spectrophotometer and the data were fitted into an open two-compartment pharmacokinetic model using the computer program (STATIS Version 3.0). Results indicated no significant difference in the absorption of paracetamol between study and control groups but a significant reduction (p < 0.05) at some sampling time as the dose of NIPRISAN was increased double-fold. The pharmacokinetic parameters showed only 1.51 and 7.19% reduction in AUC(0-infinity) and Cmax respectively for paracetamol (20 mg/kg) + NIPRISAN (500 mg/kg). It was thus concluded that the gastric presence of NIPRISAN did not significantly reduce the absorption of paracetamol in rats.

Antinociceptive activity of Zizyphus spina-christi root bark extract

The antinociceptive effect of the aqueous extract of Zizyphus spina-christi root bark was investigated in mice and rats. Acetic acid-induced writhing, formalin and thermal (hot plate) tests were used. The extract (50 and 100 mg/kg, i.p.) showed a dose-dependent analgesic effect in all the tests used. Its i.p. LD50 in mice was 2236.07 mg/kg.

Spasmolytic activity of methyl angolensate: a triterpenoid isolated from Entandrophragma angolense

Entandrophragma angolense is a medicinal plant used in folk medicine against several diseases including peptic ulcer. Methyl angolensate was isolated from E. angolense by recrystallization from methanol. The needle-like crystals were characterized and tested on isolated rabbit jejunum, guinea pig ileum and the rat fundus strip. The compound was also evaluated on the gastrointestinal transit in mice. The results showed that the compound exerted significant concentration dependent inhibition of smooth muscle and reduced the propulsive action of the gastrointestinal tract in mice. The relaxation observed did not attenuate acetylcholine and histamine induced contractions, but was found to inhibit contractions induced by serotonin. It is therefore suggested that methyl angolensate may exert its activity on gastrointestinal smooth muscle via serotonergic mechanisms.

Evaluation of methanolic extract of Ficus platyphylla on gastrointestinal activity

Methanolic extract of Ficus platyphylla was tested on isolated rabbit jejunum, rat duodenum and gastrointestinal motility in mice. The extract showed a biphasic effect on isolated smooth muscle. Lower concentration of extract caused contraction, while higher concentrations produced relaxation. The contractile phase was attenuated by atropine, while relaxant phase attenuated histamine induced contraction of guinea pig ileum. The extract also exhibited a dose-dependent inhibition of gastrointestinal motility. Acute toxicity test in mice established LD50 value (i.p.) of the extract to be 2000 mg/kg. Preliminary phytochemical screening of the extract gave positive test for flavonoids, tannins and saponins.

Antiplasmodial, analgesic, and anti-inflammatory activities of the aqueous extract of the stem bark of Erythrina senegalensis

The in vivo antiplasmodial, analgesic and anti-inflammatory properties of Erythrina senegalensis, an ornamental plant commonly used in Northern Nigeria for the treatment of fevers, was evaluated. Aqueous extracts of the stem bark of the plant was used for the study. The in vivo antiplasmodial activity of the aqueous extract against Plasmodium berghei was assessed using the suppressive and curative test procedures. Analgesic activity was assessed using the acetic acid (0.75%v/v) induced abdominal constriction, while the anti-inflammatory activity was evaluated on egg-albumin induced paw oedema in rats as a model of acute inflammation. The stem bark extract of E. senegalensis exhibited only slight antiplasmodial activity while significant (P<0.05) analgesic and anti-inflammatory effects were observed. Preliminary phytochemical analysis of the extract indicates the presence of alkaloids and glycosides.

Anti-sickling, analgesic and anti-inflammatory properties of 3,5-dimethoxy-4-hydroxy benzoic acid and 2,3,4-trihydroxyacetophenone

Effects of 3,5-dimethoxy-4-hydroxybenzoic acid and 2,3,4-trihydroxyacetophenone were studied on haemoglobin S (Hb S) polymerisation, analgesia and inflammation using Hb S solution, rats and mice. UV spectrophotometric procedure was used to monitor the polymerization of the Hb S. Acetic acid induced writhing in mice and egg albumin induced rat paw edema procedures were used to evaluate analgesic and anti-inflammatory activities of the compounds respectively. The results indicate that both drugs inhibit the process of polymerization significantly, possibly by direct action on the Hb S molecules. The drugs inhibited acetic acid induced pain and decreased egg albumin induced oedema. It is concluded that 3,5-dimethoxy-4-hydroxybenzoic acid and 2,3,4-trihydroxyacetophenone may have some value in the management of sickle cell disease.

Inhibitory effects of the aqueous extract of Pavetta crassipes leaves on gastrointestinal and uterine smooth muscle preparations isolated from rabbits, guinea pigs and rats

The effects of the aqueous extract of Pavetta crassipes leaves were studied on gastrointestinal and uterine smooth muscle preparations isolated from rabbit jejunum, guinea pig ileum and rat uterus. The extract produced a concentration-dependent inhibition of the spontaneous motility or elevated tone in these preparations. The inhibitory effects of the extract were not affected by pretreatment with propranolol or yohimbine, but were completely blocked by verapamil pretreatment. The results indicate the presence of biologically active substances whose action might be mediated through calcium channels. A preliminary phytochemical screening of the leaf extract of P. crassipes revealed the presence of flavonoids, tannins and anthraquinones as possible candidates for such inhibitory substances.

Effects of iloprost, prostaglandin E1 (PGE1) and prostacyclin (PGI2) on chemically and electrically induced seizures in mice

The effects of iloprost (ZK 36,374), a new chemically stable analogue of prostacyclin (PGI2), on strychnine-, pentylene-tetrazol-, and maximal electroshock-induced seizures were studied in mice. The time from the beginning of the injection of the convulsant or inducing electroshock to the stage of persistent seizures was determined, and lack of tonic hindlimb extension was regarded as inhibition of convulsions. In doses of 8 micrograms--16 micrograms kg-1 iloprost already exhibited an anticonvulsant action by markedly reducing the incidence of seizures and mortality following strychnine, pentylenetetrazol or maximal electroshock. The onset of tonic seizures was also reduced by iloprost. PGE1 and PGI2 were generally effective in 7 to 13 times higher doses than iloprost. It is suggested that the anticonvulsant activity of iloprost, PGE1 and PGI2 might involve a common basic mechanism. Due to its efficacy, iloprost is a useful tool in the investigation of the anticonvulsant action of prostaglandins.

Influence of piroxicam on the contractile action of prostaglandin E1 on the isolated rat uterus

Influence of piroxicam on the contractile response of the isolated rat uterus to prostaglandin E1(PGE1) was studied. Piroxicam and isobutylmethylxanthine (IBMX) reduced contractions of the isolated rat uterus induced by PGE1 and decreased the contraction/relaxation velocity ratio. The results suggest that piroxicam might antagonize PGE1 effects on the isolated rat uterus by enhancing relaxation via the cyclic AMP system.

Influence of levodopa, apomorphine and 3,4-dihydroxyphenylserine (DOPS) on strychnine-induced seizures in mice

The effects of levodopa, apomorphine and 3,4-dihydroxyphenylserine (DOPS) on tonic seizures elicited by strychnine were investigated in mice. Levodopa (6.25-100 mg/kg), apomorphine (0.2-0.8 mg/kg) and FLA-63 (12.5 mg/kg) profoundly delayed the onset and reduced the incidence of strychnine seizures. In addition, these drugs decreased strychnine-induced mortality. DOPS (1-16 mg/kg) apparently shortened the onset of strychnine seizures and altered strychnine-induced mortality in a dose-dependent manner; low doses (1-2 mg/kg) enhanced while moderate doses (4-8 mg/kg) reduced the mortality rate. FLA-63 (12.5 mg/kg) potentiated the anticonvulsant effect of low doses of levodopa (6.25-12.5 mg/kg) while it had no significant influence on the anticonvulsant effect of higher doses (25-100 mg/kg) of levodopa. In addition, the onset of strychnine seizure was further delayed by FLA-63. Haloperidol (0.5 mg/kg) potentiated the convulsant effect of strychnine (1 mg/kg) as well as strychnine-induced mortality. It also antagonised the protective effect of levodopa (12.5 and 100 mg/kg) against strychnine (1 mg/kg). Phentolamine (5 mg/kg) and +/- propranolol (1 mg/kg) antagonised strychnine seizures. Strychnine-induced mortality was also reduced by these drugs. In addition, the effects of DOPS (2 mg/kg) on strychnine seizures were antagonised by phentolamine and propranolol. These results indicate that enhancement of dopaminergic and noradrenergic neurotransmission respectively attenuate and potentiate strychnine seizures in mice.