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

Abstract

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 and
antidepressant-like properties. Thus, could be a potential phytotherapeutic in the management of drug-induced Parkinsonism.

Keywords: Digitaria horizontalis; neuroprotective; haloperidol; nootropic; catalepsy; antioxidants