Methanolic extract of Hibiscus asper leaves improves spatial memory deficits in the 6-hydroxydopamine-lesion rodent model of Parkinson's disease

Ethnopharmacological relevance: While the Hibiscus asper Hook.f. (Malvaceae) is a traditional herb largely used in tropical region of the Africa as vegetable, potent sedative, tonic and restorative, anti-inflammatory and antidepressive drug, there is very little scientific data concerning the efficacy of this. Aim of the study: We investigated antioxidant activity and the effects of methanolic extract of Hibiscus asper leaves on neurological capacity of male Wistar rats subjected to unilateral 6-hydroxydopamine (6-OHDA)-lesion. Materials and methods: Two model systems: 2,4-dinitrophenyl-1-picryl hydrazyl (DPPH) radical scavenging activity and beta-carotene bleaching inhibition assay were used to measure the antioxidant activities of the plan extract. We also investigated the neuroprotective effect of methanolic extract of Hibiscus asper leaves (50 and 100 mg/kg) in male Wistar rats subjected to unilateral 6-hydroxydopamine (6-OHDA)-lesion rat model. Results: Methanolic extract of Hibiscus asper leaves showed potent antioxidant and free radical scavenging activity. Chronic administration of methanolic extract (50 and 100 mg/kg, i.p., daily, for 7 days) significantly reduce anxiety-like behavior and inhibit depression in elevated plus-maze and forced swimming tests, suggesting anxiolytic and antidepressant activity. Also, spatial memory performance in Y-maze and radial arm-maze tasks was improved, suggesting positive effects on memory formation. Conclusions: Taken together, our results suggest that the methanolic extract of Hibiscus asper leaves have antioxidant effects and might provide an opportunity to management neurological abnormalities in Parkinson's disease conditions. (C) 2010 Elsevier Ireland Ltd. All rights reserved.