Anticonvulsant activity of aqueous fraction of Carissa edulis root bark.

CONTEXT: Carissa edulis Vahl (Apocynaceae) is used in Nigerian folk medicine to manage a plethora of diseases including epilepsy, cancer, and inflammation; its efficacy is widely acclaimed among communities of northern Nigeria. OBJECTIVE: This study establishes anticonvulsant activities of aqueous fraction of ethanol root bark extract of Carissa edulis (RAF) and sub-fractions (S1 and S2) in animal models. MATERIALS AND METHODS: We evaluated the acute toxicity of the RAF, S1 and S2, and the anticonvulsant activity using pentylenetetrazole (PTZ), picrotoxin, strychnine, N-methyl-d-aspartate (NMDA), isoniazid (INH), and aminophylline-induced seizures in mice. Their effects on maximal electroshock (MES) and kindling-induced seizures were studied in chicks and in rats, respectively, and in the electrophysiological study. The doses used for RAF were 150, 300, and 600 mg/kg while S1 and S2 were 250, 500, and 1000 mg/kg. Both RAF and sub-fractions were administered once during the experiment. RESULTS: The intraperitoneal LD50 of the RAF was estimated to be 2222.61 mg/kg and that of the S1 and S2 were above 5000 mg/kg. RAF protected the mice by 50% while sub-fractions by 16.67% against PTZ-induced seizures. RAF offered 33.33 and 16.67% protection against strychnine and NMDA models, respectively. However, RAF offered 66.67-33.33% protections against aminophylline-induced seizures at doses of 150 and 600 mg/kg, but RAF, S1, and S2 had no effect on MES-induced seizures. DISCUSSION AND CONCLUSION: Our results validate the use of the plant traditionally in the management of epilepsy, thus supporting the appraisal of biologically active components of this plant as antiepileptic agents.

Antihyperglycaemic activity of the stem-bark extract of Tamarindus indica L. on experimentally induced hyperglycaemic and normoglycaemic Wistar rats.

Diabetes is the most common endocrine disease and its prevalence is reaching epidemic proportion worldwide. In 2002, WHO Expert Committee on diabetes mellitus recommended an urgent and further evaluation of the folkloric methods of managing the disease. In response to this recommendation, several medicinal plants are currently being investigated for their hypoglycaemic activity and one of such plants is Tamarindus indica. Tamarindus indica is a slow growing tree that is resistant to strong winds and perennial. The stem-bark extract of the plant is used locally for the management of diabetes. The stem-bark extract of Tamarindus indica L. was investigated for its hypoglycemic action on experimentally induced hyperglycaemic Wistar rats using a single dose of alloxan monohydrate (150 mg kg(-1) IP). The oral LD50 of the extract was found to be greater than 5,000 mg kg(-1). Phytochemical screening revealed the presence of carbohydrates, glycosides, saponins, flavonoids, cardiac glycosides, tannins, alkaloids and triterpenes. The 1000 mg kg(-1) dose of the extract lowered the blood glucose level significantly (p < 0.05) at the 4th, 8th and 16th h. The 500 mg kg(-1) lowered the BGL significantly (p < 0.05) throughout the study. In the oral glucose load method the 1000 mg kg(-1) dose of the extract significantly (p < 0.05) lowered elevated blood glucose at the 3rd and 5th. The 500 mg kg(-1) lowered the blood glucose from the 1st to the 5th, while the 250 mg kg(-1) also lowered the blood glucose level but only significantly at the 5th h. The extract is practically non toxic when administered orally. The stem-bark extract of Tamarindus indica Linn significantly lowered elevated Blood Glucose concentration (BGL) in the experimental animal models, while the crude extract was able to prevent an elevation in BGL when used in the oral glucose load model.

Psychopharmacological properties of saponins from Randia nilotica stem bark.

CONTEXT: Decoctions of Randia nilotica Stapf. (Rubiaceae) have been used in the Nigerian traditional medicine for the management of epilepsy, anxiety, depression and psychosis for many years and their efficacies are widely acclaimed among the rural communities of Northern Nigeria. OBJECTIVE: The aim of this study is to establish whether the saponins present in R. nilotica are responsible for its acclaimed beneficial effects in Nigerian traditional medicine. MATERIALS AND METHODS: The behavioural properties of the saponin-rich fraction (SFRN) of R. nilotica stem bark were studied on hole-board, diazepam-induced sleep, rota-rod and beam-walking in mice. The anticonvulsant properties of SFRN were also examined on maximal electroshock, pentylenetetrazole- and strychnine-induced seizures in mice. RESULTS: The intraperitoneal LD50 of SFRN in mice and rats were estimated to be 11.1 and 70.7 mg/kg, respectively. SFRN significantly prolonged the duration of diazepam-induced sleep; diminished head dip counts in the hole-board test and protected mice against maximal electroshock seizures. SFRN failed to protect mice against pentylenetetrazole- and strychnine-induced seizures; and had no effect on motor coordination on the rota-rod treadmill at the doses tested. SFRN significantly decreased the number of foot slips in the beam-walking assay in mice with no effect on time to reach the goal box. DISCUSSION AND CONCLUSION: This study provides evidence of the psychopharmacological effects of SFRN, thus supporting further development of the psychoactive components as remedies for epilepsy.

Safety assessment of the standardized extract of Carissa edulis root bark in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Preparations of Carissa edulis (Vahl) have been used in the Nigerian traditional medicine for the management of fever, sickle cell disease, epilepsy, pain and inflammation for many years and their efficacy is widely acclaimed among the Hausa communities of northern Nigeria. AIM OF THE STUDY: The present studies aimed at evaluating the toxicological properties of the standardized ethanol extract of C. edulis root bark in rats, in order to determine its safety and to complement earlier efficacy studies on this widely used medicinal plant. MATERIALS AND METHODS: High performance liquid chromatography (HPLC) and preliminary phytochemical analysis of the extract were conducted and its oral median lethal dose (LD50) determined. Signs of toxicity, body weight changes, relative organs weight, feed and water consumption were monitored following 28 days of daily oral administration of graded doses of the extract in rats. Effects of the extract on sex hormones, low- and high-density lipids, hematological and biochemical parameters were examined and pathological changes of the vital organs after treatment with the extract were also investigated. RESULTS: The oral LD50 of the extract was estimated to be >5000 mg/kg. The body weights of treated rats increased progressively, but the changes were not significantly different from the control groups. The extract neither produces significant changes in feed and water consumption nor affected the relative organs weight. Although some variations were observed in hormonal and lipid profiles hematological and biochemical indices, these important parameters were normal and within acceptable limits. No lesions or pathological changes of the organs attributable to treatment with the extract were observed from the pathological examinations. The HPLC fingerprint of the extract shows a spectrum profile characteristic of C. edulis, while the preliminary phytochemical screening revealed the presence of saponins, flavonoids, tannins, anthraquinones and cardiac glycosides. CONCLUSION: Our results provided evidence that short-term administration of the standardized ethanol extract of C. edulis root bark at doses lower than 1000 mg/kg is safe in rats and may not exert severe toxic effects.

Behavioral properties of Balanites aegyptiaca in rodents.

ETHNOPHARMACOLOGICAL RELEVANCE: Balanites aegyptiaca is a native plant from the dry tropical areas of Africa and Arabia. It has been used in traditional medicine to treat psychoses, epilepsy, rheumatism and for the management of cough, liver and spleen conditions for many years. The plant is also used as antihelmintic and molluscicide. AIM OF THE STUDY: The present studies aimed at investigating the behavioral properties of ethanol extract of the root of this medicinal plant, which is already in common applications in the Nigerian traditional medicine. MATERIALS AND METHODS: The intraperitoneal and oral mean lethal dose (LD(50)) of the extract was determined using the Lorke's method. The preliminary phytochemical screening of the extract was carried out to identify the secondary metabolites in the extract. Furthermore, the behavioral properties of the extract were evaluated using diazepam-induced sleep, open field test, staircase test and beam walking assay all in mice. RESULTS: The extract significantly (p<0.001) prolonged the duration diazepam (20mg/kg i.p)-induced sleep in mice dose dependently. However, the extract showed no significant effect on the onset of diazepam-induced sleep. In the open field test, the extract (150 and 300 mg/kg) and diazepam (0.05 mg/kg) produced a significant (p<0.05, p<0.005 and p<0.001) decrease in the number of square crossings. There was no significant effect on the number of centre square crossing following the administration of the extract. The extract (75 and 150 mg/kg) and diazepam (0.05 mg/kg) produced a significant (p<0.05) decrease in the number of rearing suggestive of sedation. In the staircase experiment there was a decrease in the number of upward step climbing as well as number of rearing suggesting anxiolytic and sedative properties of the extract. In the beam walking assay the extract did not produce any significant increase in the time taken to complete task as compared to diazepam 1mg/kg which was significant at p<0.05. Furthermore, 30 mg/kg of the extract and diazepam 1mg/kg showed significant (p<0.05) mean number of foot slips, suggesting that the central nervous system depressant activity might not necessarily due to peripheral neuromuscular blockade. CONCLUSION: The result indicates that the extract of Balanites aegyptiaca possess biologically active compound(s) that have anxiolytic and sedative properties, which support the ethnomedicinal use of the plant as antipsychotic and antiepileptic agents.

Anticonvulsant activity of Carissa edulis (Vahl) (Apocynaceae) root bark extract.

AIM OF THE STUDY: To investigate the anticonvulsant activity of root bark extract of Carissa edulis. MATERIALS AND METHODS: The median lethal dose (LD(50)) of Carissa edulis extract was determined using Lork's method (1983). The anticonvulsant activity of the extract was assessed in pentylenetetrazole (PTZ)-induced convulsion in mice and maximal electroshock test (MEST) in chicks, with benzodiazepine and phenytoin as standard drugs, respectively. While mechanistic studies were conducted using both flumazenil, a GABA(A)-benzodiazepine receptor complex site antagonist and naloxone a non-specific opioid receptor antagonist. RESULTS: The median lethal dose (LD(50)) of Carissa edulis was 282.8mg/kg and over 5000mg/kg following intraperitoneal and oral administration, respectively. Carissa edulis produced 40% and 20% protection against convulsion at 5 and 20mg/kg, respectively, compared with 100% protection with benzodiazepine. The mean onset and percentage protection against convulsion in Carissa edulis extract-treated mice were reduced by flumazenil and naloxone. Carissa edulis exhibited dose-dependent inhibition of the convulsion induced by MEST with 20mg/kg providing 90% protection while phenytoin (20mg/kg) produced 100% protection. CONCLUSION: These results suggest that Carissa edulis possesses biologically active constituent(s) that have anticonvulsant activity which supports the ethnomedicinal claims of the use of the plant in the management of epilepsy.

Behavioural effects of the methanolic root bark extract of Securinega virosa in rodents.

Securinega virosa is used traditionally as sedative in children and in mental illnesses. In this study, the behavioral effects of methanolic root bark extract of S. virosa were investigated in mice. The results revealed that the extract significantly (P<0.05) and dose-dependently reduced the onset and prolonged the duration of sleep. The extract significantly (P<0.05) decreased exploratory activity and reduced the rate of apomorphine-induced stereotyped climbing at the doses tested (6.25-25 mg/kg). It also produced a significant and dose-dependent motor coordination deficit in mice at the doses tested (P<0.01). The intraperitoneal median lethal dose in mice was 774.6 mg/kg while the preliminary phytochemical screening revealed the presence of alkaloids, tannins, saponins and flavonoids. These results suggest that methanolic root bark extract of S. virosa contains biologically active principles that are sedative in nature and lend pharmacological credence to the ethnomedical use of the plant.

Psychopharmacological Properties of the Saponin Fraction of Ficus Platyphylla Stem Bark

The psychopharmacological effects of a saponin-rich fraction (SFG) obtained from crude methanolic extract of Ficus platyphylla stem bark were studied on spontaneous motor activity (SMA); pentobarbitalinduced sleep; motor coordination; amphetamine-induced hyperactivity and stereotyped behaviour; catalepsy; forced swim and tail suspension tests in rodents. SFG reduced SMA dose dependently; suggesting that it may contain psychoactive principles with sedative effects. The fraction shortened the onset and prolonged the duration of pentobarbital-induced sleep; which confirmed its sedative properties. The fraction diminished immobility time in forced swim and tail suspension tests; which is indicative of antidepressant properties. It attenuated amphetamine-induced hyperactivity and stereotyped behaviour; induced catalepsy and exacerbated haloperidol-induced catalepsy in rodents; but had no effect on motor coordination in the treadmill experiment at the doses tested. These effects were similar to those of classical neuroleptics and antidepressants. Our study provides scientific evidence of psychopharmacological effects of the saponin fraction of Ficus platyphylla stem bark and therefore supports further development of its psychoactive components as antipsychotics and antidepressants

Effect of Ingestion of Ethanol Extract of Garcinia Kola Seed on Erythrocytes in Wistar rats.

The objective of this study is to investigate the effect of ingestion of crude ethanol extract of Garcinia kola seed on erythrocytes. Fifty male Wistar rats with average weight of 200g were divided into 5 treatment groups of 10 rats per group. Group A, served as the control and was fed with standard animal feed only while groups B, C, D and E which were the treatment groups, in addition were force-fed 2 g/kg/rat/day of the Ethanol extract of Garcinia kola seed for 1, 2, 3, and 4 weeks respectively by means of an endogastric tube and syringe. At the end of the experimental period for each group the animals were sacrificed and the erythrocyte number, packed cell volume (PCV), and heamogloin concentration values were determined. The result on analysis showed that erythrocyte-count, PCV and haemoglobin concentration values showed significantly decreased values [P < 0.05] between group B (week 1) and Group A, but groups C, D and E values showed a steady rise which were not significant [P < 0.05] when compared with Group A. None of the values fell below the normal physiological range of the experimental animals. This shows that Garcinia kola seed which has flavonoids as its active constituent has no long term significant toxicological implication with respect to the concentration given on the erythrocytes of mammals.

Some effects of oestrogens on [3H]-mepyramine binding in rat brain.

Oestrogen depress [3H]-mepyramine binding in the amygdala, hypothalamus and cerebral cortex of rats. These effects of oestrogens are prevented by concurrent administration of inhibitors of cyclic 3'5' AMP phosphodiesterase, suggesting that the hormones act by reducing the activity of adenylate cyclase.