C. Wambebe

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.

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.

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.

Antinociceptive and smooth muscle contracting activities of the methanolic extract of Cassia tora leaf.

The leaves of Cassia tora Linn. (Family: Caesalpiniaceae) were soxhlet extracted with methanol. The spasmogenic effects of the extract were evaluated on guinea pig ileum, rabbit jejunum and mice intestinal transit. Antinociceptive activity of the extract was also evaluated in the mice. The LD(50) values of the extract in mice were >2000 mg/kg i.p. and p.o. The extract contracted smooth muscles of guinea pig ileum and rabbit jejunum in a concentration-dependent manner. Atropine reversibly blocked this activity. Mepyramine also reduced the contractile amplitude due to the extract in a concentration-dependent manner. The extract increased intestinal transit in mice dose dependently. C. tora extract significantly (P<0.05) reduced the number of acetic acid induced abdominal constrictions in mice and the effect was comparable to that of aspirin (150 mg/kg i.p.). The extract also significantly (P<0.05) reduced the nociceptive response of mice to increased force (g). The effects were dose-dependent. The studies suggest that the use of C. tora, traditionally, as a purgative and in the treatment of other ailments is justifiable.

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.

Pharmacological evidence favouring the use of Nauclea latifolia in malaria ethnopharmacy: Effects against nociception, inflammation, and pyrexia in rats and mice

AIM OF THE STUDY Nauclea latifolia Smith is used traditionally in the treatment of uncomplicated malaria and painful conditions among its several other applications. The objective of this study is to investigate the pharmacological activities of the plant relevant to the symptomatic treatment of malaria fever and other painful conditions as an initial step towards developing an effective therapy for the symptomatic management of malaria fever and relief of other painful conditions. MATERIALS AND METHODS Various concentrations of the aqueous extract of the root bark of this plant were evaluated for its anti-nociceptive, anti-inflammatory and anti-pyretic activities in mice and rats. Investigation of the anti-nociceptive activities was performed using the acetic acid-induced abdominal constriction and hot-plate tests in mice and formalin-induced pain test in rats, as models of nociception. The extract was also investigated for its effect against inflammation induced by egg-albumin and pyrexia induced by yeast in rats. RESULTS Our data showed that the aqueous extract of Nauclea latifolia root bark (50-200mg/kg p.o.) significantly (P<0.05) attenuated writhing episodes induced by acetic acid and increased the threshold for pain perception in the hot-plate test in mice, dose-dependently. The product also remarkably decreased both the acute and delayed phases of formalin-induced pain in rats and also caused a significant reduction in both yeast-induced pyrexia and egg-albumin-induced oedema in rats. These effects were produced in a dose-dependent manner. CONCLUSION The results suggest the presence of biologically active principles in the extract with anti-nociceptive, anti-inflammatory and anti-pyretic activities that justifies its use in malaria ethnopharmacy and subsequent development for clinical application.

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.

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.

Some behavioural and EEG effects of ascorbic acid in rats

Ascorbic acid (50–200 mg/kg IP) activated gross behaviour and EEG of rats. The behavioural excitation induced by d-amphetamine (2.5 mg/kg SC) was significantly potentiated by ascorbic acid (100–200 mg/kg IP). Catalepsy induced by haloperidol (0.25 mg/kg IP) was attenuated by ascorbic acid (50–200 mg/kg IP) while pentobarbitone (20 mg/kg IP)-induced sleep in rats was dose-dependently antagonised by ascorbic acid (50–400 mg/kg IP). Ascorbic acid (50–400 mg/kg IP) desynchronized the EEG of the frontal cortex and optic cortex while the EMG activity was slightly enhanced in the rat. Ascorbic acid (100 mg/kg IP) potentiated d-amphetamine (2.5 mg/kg SC)-induced EEG desynchronization and EMG activation in the rat. These results indicate that ascorbic acid exerts stimulatory effects in rats. The results also suggest that dopaminergic mechanism may contribute indirectly or directly to the observed behavioural and EEG effects of ascorbic acid.

Evaluation of Nigerian traditional medicine : effects of Gakani, a herbal anti-asthmatic drug

The anti-asthmatic potential of Gakani, a popular herbal drug in Nigeria was investigated. The LD50 values of the freeze-dried aqueous extract in mice and rats were 20.9 +/- 2.4 mg/kg and 18.6 +/- 4 mg/kg, respectively. The extract unsurmountably blocked the effects of histamine and isoprenaline on the guinea pig tracheaL chain. It produced initial dose-related contractions of the isolated guinea pig ileum and rat stomach strip, which was followed by persistent autoinhibition and inhibition of histamine- and 5-hydroxytryptamine (5-HT)-induced responses of the two preparations, respectively. The extract had good anti-inflammatory effect in rats, causing a dose-related inhibition of the increase in the paw circumference (acute inflammation) induced by subplantar injection of fresh egg albumin. These results highlight the anti-asthmatic and toxic potential of this preparation and the need for a systemic approach in the study of traditional medicines.