Ethnopharmacology-aided antiplasmodial evaluation of six selected plants used for malaria treatment in Nigeria.

ETHNOPHARMACOLOGICAL RELEVANCE: Sub - Saharan Africa has a high malaria burden and Nigeria accounts for majority of malaria cases worldwide. The aim of this study was to evaluate selected plants extracts used against malaria in Nigeria for antiplasmodial activity. MATERIALS AND METHODS: An ethnomedicinal based - approach by literature survey was used to identify plants used in the study. The parts of the plant used were collected and extracted with 70% v/v ethanol; a portion of each extract was used to prepare successive solvent and residual fractions. Chloroquine-sensitive (3D7) P. falciparum strain and human embryonic kidney cells (HEK293) were used for antiplasmodial and cytotoxicity screening respectively. Hemolysis assay was also carried out on red blood cells (RBCs). Test for in vivo efficacy of an active extract was conducted in a mouse model of established P. berghei ANKA-infection. RESULTS: A total of six plants; Andropogon schirensis, Celtis durandii, Chasmanthera dependens, Daniellia ogea, Icacina trichantha and Triumfetta cordifolia were selected and screened. Triumfetta cordifolia leaf extract was observed to display moderate in vitro antiplasmodial activity (IC50 = 48.09 µg/ml) and was non-toxic to HEK293 cells and erythrocytes. At a dose of 400 mg/kg, T. cordifolia significantly (p<0.001) suppressed parasitemia, significantly (p<0.001) inhibited RBC depletion and prolonged survival in infected mice. CONCLUSIONS: T. cordifolia ethanol extract possesses antiplasmodial efficacy and this is the first report of its kind on the plant. It is a potential candidate for further studies to identify its mechanism of action.

Anti-inflammatory, Anti-nociceptive and Total polyphenolic Content of Hydroethanolic Extract of Ocimum gratissimum L. Leaves.

Ocimum gratissimum has been reported in several ethnopharmacological surveys as a plant readily accessible to the communities and widely used with a lot of therapeutic potentials. In this study, we aimed to experimentally evaluate the anti-inflammatory effects of hydro-ethanolic extract in animal models of inflammation and nociception and membrane stabilization assay. O gratissimum leaves hydroethanolic extract was subjected to phytochemical screening and spectrophotometric quantification of polyphenolics. The extract was investigated for anti-inflammatory effects in carrageenan -induced paw oedema and cotton pellet - induced granuloma in rats. The antinociceptive effects were investigated in acetic acid -induced writhing in mice and formalin test in rats. Animals were randomly divided into groups; negative control, extract treated (200 -800 mg/kg) and indomethacin (10 mg/kg) standard reference groups. In- vitro anti-inflammatory activity was performed by testing for membrane stability in heat/hypotonic solution -induced rat erythrocytes destabilization assay. Phytochemical screening revealed presence of saponins, tannins, alkaloids, flavonoids, terpenoids, and cardenolides. Quantification of the polyphenolic content revealed the presence of appreciable quantities of phenolics and flavonoids. Carrageenan-induced paw oedema, cotton-pellet granuloma, acetic acid -induced writhing and formalin induced paw licking tests showed that hydroethanolic extract of O gratissimum possess anti-inflammatory and anti-nociceptive effects. The extract did not induce gastric lesion formation in stomach of cotton-pellet granuloma rats. The extract was more efficient at reducing membrane destabilization than indomethacin in the membrane stability assay. These results suggest that hydroethanolic extract of O gratissimum leaves exhibits anti-inflammatory and anti-nociceptive effects in the animals.

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.

Antinociceptive and antipyretic activities of the Zizyphus oxyphylla Edgew. leaves.

A methanol extract of Zizyphus oxyphylla Edgew leaves has been investigated for its analgesic and antipyretic activities in Adult Wistar and Swiss albino mice of either sex at 50, 100 and 200 mg/kg orally. The extract demonstrated marked antipyretic activity against Brewer's yeast-induced pyrexia in rats. The extract demonstrated significant peripheral analgesic effect in the acetic acid-induced writhing test in mice. The phytochemical tests revealed that the extract contained alkaloids, anthraquinones, flavonoids, glycosides, phenols, resins, saponins and tannins using standard procedures. In conclusion, the present study suggests that the methanol extract of Zizyphus oxyphylla Edgew leaves possesses potent antipyretic and antinociceptive activities and thus validates its use in the treatment of pain and fever.

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 Annona senegalensis rootbark extracts on Naja nigricotlis nigricotlis venom in rats.

Annona senegalensis Pers (family: Annonaceae) is used traditionally in Nigeria to treat victims of snakebite. The potency of the methanol extract of the root bark of the plant was tested against cobra (Naja nigricotlis nigricotlis Wetch) venom in rats. The extract was also tested on brine shrimp (Artemia saline Leach). The activity of the extract against the venom induced mortality, occurrence of toxic signs, activity on liver enzymes as well as its ability to reverse experimentally induced increase in body temperature were evaluated. Results indicated that the extract caused reduction in the induced hyperthermia and directly detoxified the snake venom used by 16-33%. It, however, failed to restore the biochemical functions (sGOT and sGPT) of the liver. The extract exhibited an LC(50) of 232.7 microg/ml in the brine shrimp test.

The efficacy of Sphaeranthus senegalensis Vaill extract against diarrhoea in rats.

The aqueous extract of Sphaeranthus senegalensis (Asteraceae) was investigated for anti-diarrhoeal activity in rats. Its effect on castor oil-induced diarrhoea and fluid accumulation and on gastrointestinal (charcoal meal) test was evaluated. Results showed that pre-treatment for 30 min with the extract at 50, 100 and 200 mg/kg, p.o. causes a dose-dependent protection against castor oil-induced diarrhoea and intraluminal fluid accumulation and inhibited gastrointestinal transit motility. These results suggest that the plant contain active constituents that may be useful against diarrhoea.

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.

Anti-inflammatory and anti-nociceptive effects of Sphaeranthus senegalensis.

Sphaeranthus senegalensis Vaill (Asteraceae) is used in traditional medicine as a remedy for rheumatic pains and other ailments. The anti-inflammatory and anti-nociceptive activity of the aqueous extract of the whole shoot of the plant was evaluated in mice and rats. Activity of the extract against egg-albumin induced hind paw oedema was measured to evaluate the anti-inflammatory activity while the anti-nociceptive potency was evaluated using three painful stimuli viz acetic acid induced abdominal constriction and hot plate test in mice, and the formalin test in rats. Results indicated that the extract possess remarkable dose dependent anti-inflammatory activities in rats. The extract also showed anti-nociceptive activities against acetic acid induced writhing, formalin and the hot plate pain models. The effects were significant (P < 0.05) when compared with the saline control group. The results suggest the presence of a potent anti-inflammatory and anti-nociceptive principle in the extract, which support the folkloric use of the plant in relieving rheumatic pains.

Neuropharmacological screening of Diospyros mespiliformis in mice.

The neuropharmacological activities of the aqueous extract of Diospyros mespiliformis stem bark were screened in mice. The extracts effect on pentobarbital-induced sleeping time, pentylenetetrazole induced seizure, spontaneous motor activity (SMA), exploratory behaviour, and rota-rod performance (motor coordination) were evaluated. The extract (100 and 200 mg/kg p.o.) produced a significant (P<0.05) prolongation of pentobarbital-induced sleeping time, and reduced the SMA and exploratory behaviour. The extract prolonged onset of the phases of seizure activity but did not protect mice against lethality induced by pentylenetetrazole. It also failed to affect the motor coordination test. These results suggest that the extract contained an agent with neuropharmacological activity that may be sedative in nature.

Pharmacological evidence favouring the folkloric use of Diospyros mespiliformis Hochst in the relief of pain and fever.

The methanol extract of Diospyros mespiliformis was evaluated for its claimed folkloric usage in the relief of pain and fever. Antipyretic, analgesic and anti-inflammatory effects of the extract were evaluated in rats and mice. Studies were carried out on yeast-induced pyrexia in rats, acetic acid-induced writhing in mice, formalin test and egg albumin-induced anti-inflammatory activity in rats. The extract (50 and 100 mg/kg i.p.) gave a potent antipyretic effect for 100 mg/kg and significant activity (P<0.05) against all the analgesic and anti-inflammatory models used. The LD(50) of the extract was estimated to be 513.80+/-33.92 mg/kg i.p. in mice. These results provide support for the use of the plant in relieving pain and fever.

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.

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.

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.

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.