Modulation of Memory and Neurochemical Changes by Resveratrol and Environmental Enrichment in Rodent Model of Alzheimer's Disease.

Alzheimer's disease (AD) is the most common cause of dementia that affects one patient every seven seconds, with over 35 million people currently affected worldwide. The aim of the study was to investigate the modulation of memory and neurochemical responses by resveratrol and environmental enrichment (EE) in aluminium chloride (AlCl3) model of Alzheimer's disease in mice. Male mice used for the study were divided into nine groups, of seven animals each. Group I (negative control): 0.2 ml normal saline/kg, Group II: 0.2 ml CMC/kg. Group III: resveratrol (200 mg/kg/), Group IV: CMC and kept in EE, Group V: AlCl3 at dose of 50 mg/kg, Group VI: resveratrol at dose of 200 mg/kg and kept in EE, Group VII: AlCl3 (50 mg/kg) + resveratrol (200 mg/kg), Group VIII: AlCl3 (50 mg/kg) and kept in EE, Group IX: AlCl3 (50 mg/kg) + resveratrol (200 mg/kg) and kept in enriched environment. All treatments were oral and lasted for 8 weeks. Assessments of memory was carried out before treatment, and at weeks 4 and 8, after the first treatment. The mice were sacrificed and hippocampal samples collected for neurochemical analysis. The findings of the study suggest that AlCl3 induced contextual fear memory deficit over time (p < 0.05), which was improved by resveratrol. Both Aß and Nrf2 significantly (p < 0.05) increased in AlCl3 + EE + resveratrol group. In conclusion, Individual treatment with either resveratrol or EE improved memory over the combined treatment in AlCl3 model of AD by decreasing Aß protein concentration.

Anticonvulsant properties of methanol leaf extract of Laggera Aurita Linn. F. (Asteraceae) in laboratory animals.

ETHNOPHARMACOLOGICAL RELEVANCE: Preparation of Laggera aurita Linn. (Asteraceae) is widely used in traditional medicine to treat various kinds of diseases such as epilepsy, malaria, fever, pain and asthma. Its efficacy is widely acclaimed among communities in Northern Nigeria. AIM OF THE STUDY: The present study is aimed at establishing the possible anticonvulsant effects of the methanol leaf extract of Laggera aurita using acute and chronic anticonvulsant models. MATERIALS AND METHOD: Median lethal dose (LD50) was determined in mice and rats via oral and intraperitoneal routes. Anticonvulsant screening of the extract was performed using maximal electroshock-induced seizure test in day-old chicks; pentylenetetrazole-, strychnine- and picrotoxin- induced seizure models in mice. Similarly; its effects on pentylenetetrazole-induce kindling in rats as well as when co-administered with fluphenamic and cyproheptadine in mice, were evaluated. RESULTS: Median lethal dose (LD50) values were found to be >5000mg/kg, p.o. and 2154mg/kg, i.p., each for both rats and mice. The extract showed dose dependent protection against tonic hind limb extension (THLE) and significantly (p<0.05) decreased the mean recovery from seizure in the maximal electroshock-induced seizure. In the pentylenetetrazole-induced seizure model, the extract offered 50% protection at 600mg/kg and also increased the mean onset of seizure at all doses with significant (p<0.05) increase at the highest dose (600mg/kg). Similarly the extract produced significant (p<0.05) increase in the onset of seizures in both strychnine- and picrotoxin- induced seizure models, at all the doses except at 150mg/kg for the picrotoxin model. Co-administration of fluphenamic acid (FFA) (5mg/kg) and the extract (600mg/kg) showed an enhanced effect with percentage protection of 70% while co-administration of FFA (5mg/kg) and phenytoin (5mg/kg) as well phenytoin (5mg/kg) and the extract (600mg/kg) produced an additive effect. Administration of the extract (600mg/kg), phenytoin (20mg/kg) and cyproheptadine (4mg/kg) offered 40%, 100% and 0% protection against THLE, each respectively, while co-administration of cyproheptadine (4mg/kg) and the extract (600mg/kg) as well as co-administration of cyproheptadine (4mg/kg) and phenytoin (20mg/kg) offered reduced protection of 20% and 50% each respectively. The extract at all doses reduced the severity of seizure episodes induced by PTZ-induced kindling. CONCLUSION: The results suggest that the methanol leaf extract of Laggera aurita possesses anticonvulsant and antiepileptogenic properties.

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.