Protective effect of Tetrapleura tetraptera (Schum. & Thonn.) fruit extract against haloperidol-induced catalepsy and scopolamine-induced memory impairment: Involvement of antioxidant system

Tetrapleura tetraptera fruit infusion is taken as a recuperative tonic and memory enhancer in the traditional African medicine. This study investigates the  neuroprotective and memory enhancing effects of T. tetraptera. The ethanolic fruit extract of Tetrapleura tetraptera (HeTA) (25-100 mg/kg, p.o) was administered for 3 consecutive days, scopolamine (3 mg/kg, i.p.) or haloperidol (1 mg/kg, i.p.) given 1 h post-treatment on day 3. The bar test, elevated plus maze test (EPM) and Morris water maze paradigm (MWM) were used to evaluate the effect of the extract on cataleptic behaviour and memory function, respectively. Biochemical markers of oxidative and nitrosative stress were estimated in rats’ brains after the completion of the MWM task. Haloperidol injection induced time course cataleptic behaviour which was reversed by HeTA (25-100 mg/ kg) treatment in bar test. Scopolamine injection impaired memory function in the EPM and MWM tasks. However, HeTA (25-100 mg/kg) administration significantly (P<0.001) reduced the transfer latency in the EPM as well as session dependent decrease (P<0.001) in escape latency in MWM. Also, HeTA and tacrine improved spatial learning evidenced in the increase (P<0.01) time spent in the target quadrant in the MWM. Moreover, scopolamine increased (P<0.05-0.001) the levels of lipid peroxidation and nitrite generation with concomitant decrease (P<0.05-0.001) in antioxidant enzymes activities in the prefrontal cortex, striatum and hippocampus which were ameliorated with the pretreatment of rats with HeTA or tacrine. Findings from this study indicate anticataleptic and memory enhancing effects of T. tetraptera fruit extract through enhancement of antioxidant defense systems.Keywords: Dementia; elevated plus maze; Morris water maze; scopolamine; malondialdehyde; 1,1-Diphenyl- 2-picrylhydrazyl (DPPH

Ameliorative effect of the hydroethanolic whole plant extract of Digitaria horizontalis (Poaceae) against haloperidol-induced catalepsy in mice

Background: Digitaria horizontalis is used in Traditional African Medicine in the management of nervous disorders.Objective: This study was carried out to investigate the protective effect of hydroethanolic whole plant extract of D. horizontalis 1 against haloperidol-induced catalepsy in mice.Methods: Male albino mice (17-21 g) randomly divided into six groups (n=6); (1) normal saline, vehicle control (10 ml/kg), (2) vehicle positive control, (3) trihexylphenidyl (0.5 mg/kg, i.p.), (4-6) DH (12.5, 50 or 100 mg/kg), 1 h posttreatment haloperidol (1 mg/kg, i.p.) for 14 consecutive days. The neurobehavioral effect of the extract was evaluated using the bar, open field, elevated plus maze, forced swim and climbing tests. At the end of the study, biochemical markers of nitrosative and oxidative stress status were determined.Results: DH (12.5, 50 and 100 mg/kg) significantly ameliorated haloperidol-induced catalepsy (bar test), spontaneous motor and working memory deficits (open field and elevated plus maze tests, respectively), depressive-like behavior and motor coordination deficits (forced swim and climbing tests, respectively) compared to vehicle-treated control. Haloperidol injection increased level of lipid peroxidation and deficits in the level of antioxidant enzymes which was attenuated by pretreatment of mice with DH. To corroborate these findings, DH scavenged 1-1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide and ferric ion induced free radicals in vitro.Conclusion: Findings from this study suggests that the hydroethanolic whole plant extract of D. horizontalis possesses antioxidant, neuroprotective, nootropic andantidepressant-like properties. Thus, could be a potential phytotherapeutic in the management of drug-induced Parkinsonism.Keywords: Digitaria horizontalis; neuroprotective; haloperidol; nootropic; catalepsy; antioxidant

Protective effect of ethanolic leaf extract of Bacopa floribunda (r.br.) Wettst on scopolamineinduced memory impairment in rodents: A behavioural and biochemical study

Bacopa floribunda (R.Br.) Wettst (Scrophulariaceae) leaf is used in traditional African and Ayurvedic medicine as a brain tonic for promoting memory and psychological  disorders. Hence this study was designed to investigate effect of ethanolic leaf extract of Bacopa floribunda (HeBF) on memory impairment and oxidative stress induced by scopolamine in rodents. Male albino mice or rats were given HeBF (6.25, 12.5 or 25 mg/kg, p.o.) or tacrine (5 mg/kg, i.p.) for three days. On day 3, scopolamine (3 mg/kg, i.p.) was administered 1 h after last treatments, 5 min post-scopolamine administration, memory functions were assessed using Y-maze and Morris water maze tests (MWM)); from days 3-7). 1 h after the probe test on day 8, oxidative stress biomarkers were assessed in discrete brain regions of rats. Scopolamine administration significantly (P<0.01) reduced alternation behaviour and prolonged the escape latency time (ELT) in Y-maze and MWM tests, respectively. However, pretreatment with HeBF reversed the decrease in alternation behaviour in mice (F(5,30)=7.81,P<0.001) and the increase in (F (4, 29) = 24.35, P< 0.001) ELT-induced by scopolamine in rats. Similarly, HeBF treatment attenuated oxidative stress, as shown by elevated levels of malondialdehyde (F(5,72)=33.29,P<0.001), and deficits in antioxidant activity, including GSH (F(5,72)=16.39,P<0.001), catalase (F(5,72)=16.39,P<0.001) and superoxide dismutase (F(5,72)=33.29,P<0.001) in the prefrontal cortex, striatum and hippocampus of rats. Findings from this study showed that B. floribunda prevents scopolamine-induced cognitive deficit through enhancement of antioxidant defense systems. Thus, further work to isolate the active principles in B. floribunda may yield agents of therapeutic value in the management of Alzheimer’s disease. Bacopa floribunda (R.Br). Wettst (Scrophulariaceae) la feuille est utilisé dans la médecine(le médicament) africaine et Ayurvédique traditionnelle comme un fortifiant cérébral pour promouvoir la mémoire(le souvenir) et des troubles psychologiques. Par conséquent cette étude a été conçue pour examiner l’effet d’extrait de feuille ethanolic de Bacopa floribunda (HeBF) sur la diminution(déficience) de  mémoire(souvenir) et le stress oxydatif induit par scopolamine dans des rongeurs. On a donné des souris d’albinos masculines ou des rats HeBF (6.25, 12.5 ou 25 mg/kg, la BP) ou tacrine (5 mg/kg, i.p.) pendant trois jours. Jour 3, scopolamine (3 mg/kg, i.p.) a été administré 1 h après les derniers traitements, 5 minute  post-scopolamine l’administration, les fonctions de mémoire(souvenir) ont été évaluées utilisant l’Y-labyrinthe et des tests de labyrinthe d’eau de Morris (MWM)); de jours 3-7). 1 h après le test de sonde(d’investigation) jour 8, les biomarqueurs de stress oxydatif ont été évalués dans les régions cérébrales discrètes de rat. Scopolamine l’administration significativement (P0.01) le comportement  d’alternance réduit et prolongé le temps de latence d’évasion (ELT) dans l’Y-labyrinthe et MWM teste, respectivement. Cependant, le prétraitement avec HeBF a renversé la diminution dans le comportement d’alternance dans des souris (F (5,30) =7.81, P0.001) et l’augmentation (de F (4, 29) = 24.35, P 0.001) ELT-induit par scopolamine dans des rats. De même HeBF le traitement a atténué le stress oxydatif, comme indiqué par les niveaux élevés de malondialdehyde (F (5,72) =33.29, P0.001) et des déficits dans l’activité d’antioxydant, y compris GSH (F (5,72) =16.39, P0.001), catalase (F (5,72) =16.39, P0.001) et le superoxyde dismutase (F (5,72) =33.29, P0.001) dans le cortex préfrontal, striatum et hippocampus de rats. Les découvertes de cette étude ont montré que B. floribunda empêche le déficit cognitif scopolamine-induit par l’amélioration(augmentation) de systèmes de défense d’antioxydant. Ainsi, plus loin le travail pour isoler les  principes actifs dans B. floribunda peut rapporter les agents de valeur thérapeutique dans la gestion(direction) de maladie d’AlzheimerKeywords: Alzheimer’s disease; antioxidants; cholinesterase; Morris water maze; scopolamine