Phytomedicine Plus (Aug 2023)
Neuropharmacological assessment of the methanolic stem back extract of Anopyxis klaineana (Pierre) Engl. (Rhizophoraceae) in mice
Abstract
Background: Medicinal plants have recently attracted attention on a global scale for therapeutic interventions in the field of neuroscience. Anopyxis klaineana, a medicinal plant widely used in West Africa, has been studied extensively for its anti-inflammatory effects. However, studies on its neuropharmacological effects are quite limited. This study therefore assessed the neuropharmacological potential of the methanolic stem bark extract of Anopyxis klaineana (EAK) in murine models. Materials and methods: Mice were treated orally with a methanolic stem back extract of Anopyxis klaineana (EAK) at 10, 30 or 100 mg/kg followed by testing in the elevated plus-maze (EPM) and open field (OF) tests for anxiolytic-like effects. EAK's antidepressant-like potential was also evaluated in the tail suspension test (TST), while anticonvulsant and central analgesic effects were evaluated with the pentylenetetrazol (PTZ)-induced convulsion threshold and tail withdrawal tests respectively at 30, 100 or 300 mg/kg. The extract was additionally subjected to chromatographic analyses using high resolution HPLC-MS. Results: Total ion current chromatogram of EAK revealed several peaks suggestive of secondary metabolites of the plant extract. EAK significantly (p<0.05) reduced depression-like behaviours in the TST although not as potent as fluoxetine (ED50: EAK=43.39±2.5; fluoxetine=1.16±1.6) (F3,20=9.663, p = 0.0004). It also showed significant anticonvulsive effect by reducing the frequency and duration of PTZ-induced convulsions (ED50=48.53±2.5 mg/kg) (F3,19=5.136, p = 0.0091). This anticonvulsant effect was seen in both clonic and tonic convulsions at 30 and 300 mg/kg. Additionally, EAK-treated mice showed higher latency to tail withdrawal in the analgesia test. We also observed significant (p<0.05) dose-dependent increase in anxiolytic-like effects in EAK-treated animals in the EPM (F3,20=10.77, p = 0.0002) and OF tests (F3,22=5.079, p = 0.008). Conclusions: The methanolic Anopyxis klaineana stem back extract exhibits anxiolytic-like, antidepressant-like, analgesic and anticonvulsant effects in murine models for assessing neuropharmacological activity and is a good source for novel neuroactive compounds.
