ABSTRACT
BACKGROUND: Leonotis nepetifolia Linn (Lamiaceae) is used in traditional medicine for its calming (tranquilizing) effects. The aim of this study was to determine whether there is any scientific justification for this use. To achieve this purpose, we investigated the behavioural effects of the methanol extract of Leonotis nepetifolia stem (37.5, 75 and 150 mg/kg) in mice. METHODS: Acute toxicity studies were carried out on the methanol stem extract of Leonotis nepetifolia to determine the LD50. The behavioural tests employed were diazepam-induced sleep onset and duration, hole board assay for exploratory activity, mouse beam walk assay for motor coordination, and the staircase test for the detection of anxiolytic compounds. Preliminary phytochemical screening was also carried out on the extract. RESULTS: The intraperitoneal LD50 value was found to be 3.8 g/kg. The results showed that the extract significantly prolonged the duration of diazepam-induced sleep at the highest dose (150 mg/kg). There was no observable effect on exploratory activity and motor coordination at the doses tested (37.5, 75 and 150 mg/kg). The extract, however, at 150 mg/kg elicited a significant decrease in the number of rearings in the staircase test, an effect also observed in the group of mice injected with an anxiolytic dose of diazepam. The preliminary phytochemical screening revealed the presence of alkaloids, saponins, glycosides and triterpenoids. CONCLUSION: The results obtained suggest that the crude methanol extract of Leonotis nepetifolia stem possesses some biologically active constituents with potential anxiolytic activity and thus may justify its traditional use as a tranquilizer.
Subject(s)
Anti-Anxiety Agents/administration & dosage , Anxiety/drug therapy , Lamiaceae/chemistry , Plant Extracts/administration & dosage , Animals , Anti-Anxiety Agents/adverse effects , Anti-Anxiety Agents/isolation & purification , Anxiety/psychology , Behavior, Animal/drug effects , Female , Humans , Male , Mice , Plant Extracts/adverse effects , Plant Extracts/isolation & purification , Plant Stems/chemistryABSTRACT
Prosopis africana (Guill. & Perr.) Taub. (Mimosoideae) is a shrub used for menstrual and general body pain in Nupe land in north central Nigeria. In this study, the methanol extract of the stem bark of Prosopis africana (at doses of 62.5, 125, and 250 mg/kg) was evaluated for analgesic and anti-inflammatory activities using acetic acid-induced writhing assay and carrageenan-induced inflammation in rats. The extract significantly (P <0.05) attenuated the acetic acid-induced writhing with the highest activity observed at the highest dose, 250 mg/kg (76.89%) comparable to that of piroxicam (83.16%) the standard agent used. In the carrageenan-induced inflammation assay, the extract showed significant anti-inflammatory activity (P <0.001) from the third hour. The preliminary phytochemical screening revealed the presence of flavonoids, saponins, carbohydrates, cardiac glycosides, tannins, and alkaloids. The oral median lethal dose was found to be 3807.9 mg/kg in mice and > 5000 mg/kg in rats. This study supports the folkloric claim of the use of Prosopis africana in the management of pain.
Subject(s)
Analgesics, Non-Narcotic/therapeutic use , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Phytotherapy , Plant Bark/chemistry , Plant Extracts/therapeutic use , Plant Stems/chemistry , Prosopis/chemistry , Analgesics, Non-Narcotic/chemistry , Analgesics, Non-Narcotic/toxicity , Animals , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/toxicity , Dose-Response Relationship, Drug , Edema/chemically induced , Edema/prevention & control , Female , Lethal Dose 50 , Male , Medicine, African Traditional , Methanol/chemistry , Mice , Nigeria , Pain Measurement , Plant Extracts/chemistry , Plant Extracts/toxicity , Rats , Rats, Wistar , Time FactorsABSTRACT
Preparations of Ficus platyphylla have been used in Nigerian traditional medicine for the management of epilepsy for many years and their efficacy is widely acclaimed among the Hausa communities of northern Nigeria. The anticonvulsant properties of the saponin rich fraction (SFG) obtained from the methanol extract of F. platyphylla stem bark were studied on pentylenetetrazole-, strychnine- and maximal electroshock seizures in mice. Effects of SFG were also examined in murine models for neurological disease and on relevant in vitro targets for anticonvulsant drugs. SFG protected mice against pentylenetetrazole- and strychnine-induced seizures; and significantly delayed the onset of myoclonic jerks and tonic seizures. SFG failed to protect mice against maximal electroshock seizures at doses tested. SFG neither abolished the spontaneous discharges induced by 4-aminopyridine in a neonatal rat brain slice model of tonic-clonic epilepsy nor could it modulate chloride currents through GABA(A) receptor channel complex in cultured cortical cells. However, it was able to non-selectively suppress excitatory and inhibitory synaptic traffic, blocked sustained repetitive firing (SRF) and spontaneous action potential firing in these cultured cells. Our results provide scientific evidence that F. platyphylla stem bark may contain psychoactive principles with potential anticonvulsant properties. SFG impaired membrane excitability; a property shared by most anticonvulsants particularly the voltage-gated sodium channel (VGSC) blocking drugs, thus supporting the isolation and development of the saponin components of this plant as anticonvulsant agents.
