Rosemary U. Okoh-Esene*, Joseph I. Okogun and Simon K. Okwute
The mean duration of sleep in mice increased with an increased dose of the crude ethanolic extract of Hippocrateae welwitschii. The mice dosed with the extract all dropped in an open field and couldn’t maintain balance at a 45o inclined plane. These imply that the extract is sedative and affected their motor coordination. The ethanolic root extract of Hippocrateae welwitschii reduced the onset of seizure in extract-treated mice dosed with flumazenil by 0-40% (p<0.05). In addition, flumazenil completely blocked the protection provided by diazepam against seizure while the protection against seizure in Hippocratea welwitschii extract-treated mice was 20% in the presence of naloxone (opioid receptor). The fact that flumazenil reduced seizure onset and attenuated the protection against seizure provided by Hippocratea welwitschii suggest that it may contain substance(s) that interacted with the benzodiazepine site in the GABAA-benzodiazepine receptor complex. The ability of the extract to exhibit activity against these two types of seizures suggests that it may act through different mechanisms to elicit its anticonvulsant effects, such as voltage-gated sodium, calcium, and potassium or GABA-ergic pathway. The biphasic activity observed in Pentylenetetrazole (PTZ) induced studies may probably be due to the possible interaction between constituents of the crude extract.