Anxiolytic, Anticonvulsant and Antinociceptive Effects of the Hydroalcoholic Leaf Extract of Ficus Exasperata Vahl (Moraceae)

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Ficus exasperata is a common plant in sub-Saharan Africa, widely used in the management of various disorders including neurological, inflammatory and infections. The hydroalcoholic leaf extract of F. exasperata (Family Moraceae) was evaluated for its anxiolytic, anticonvulsant and antinociceptive activity in animal models. F. exasperata (30-300 mg/kg) showed anxiolytic effect similar to diazepam (0.1-1.0 mg/kg), the reference anxiolytic agent, in the open field, elevated plus maze and the hole board tests for anxiety (P< 0.01). Caffeine (10-100 mg/kg) on the other hand was found to be anxiogenic which confirms what is known in literature (P< 0.01). F. exasperata (30-100 mg/kg) decreased spontaneous locomotor activity (P<0.01) which could be due to its possible muscle relaxation effect as exhibited on the rotarod (P< 0.001). F. exasperata (300 mg/kg) decreased sleeping time induced with pentobarbitone sodium indicating a possible non-sedating nature (P< 0.001). F. exasperata (30-300 mg/kg) protected mice against picrotoxin and pentylenetetrazole (PTZ)-induced seizures. It considerably increased the latency and decreased the frequency and duration of picrotoxin induced seizure (P< 0.01). F. exasperata (1000 mg/kg) also decreased the duration of PTZ-induced seizure considerably (P<0.5). F. exasperata (30-300 mg/kg) and morphine (1-10 mg/kg), an opioid agonist dose- dependently showed anti-nociceptive activity in both phases of the formalin test. Diclofenac (10-100 mg/kg) on the other hand was not effective in the first phase but effective in the second phase (ED50 3.98±1.05). The nocifensive response for morphine was higher in the first phase (ED50 0.84±0.27) compared to the second phase (ED50 2.72±1.05) but F. exasperata was more potent in the second phase (ED50 34.08±6.50) than the first phase (ED50 187.00±49.75). Theophylline completely antagonized the anti-nociceptive effect of the F. exasperata while naloxone did not produce any significant inhibition. These results suggest F. exasperata has central and peripheral anti-nociceptive properties at the doses tested. The anti-nociceptive mechanism of F. exasperata might possibly be related to the adenosinergic system. F. exasperata did not have any significant effect on animal weight, liver microsomal enzymes, organ weight and the hematological indices investigated. F. exasperata was thus found to have anxiolytic, anticonvulsant and analgesic properties.  
A thesis submitted to College of Health Sciences in fulfillment of the requirements for the degree of Master of Philosophy, 2008