Is monofluoracetic acid the active neurotoxic principle in Palicourea marcgravii (St. Hill) leaves?

Acute intoxication of rats with the crude extract of Palicourea marcgravii (PM) and with monofluoracetic acid (MFA) solutions was compared since it has been reported that PM leaves contain monofluoracetates (455 micrograms/g air-dried material). The neurotoxic signs produced by oral administration of PM and MFA were similar and included tonic-clonic seizures. The dose-response curves constructed for the convulsant effects of PM and MFA were parallel and the CD50s were 630 mg/kg (508-781) and 0.90 mg/kg (0.76-1.06), respectively. These data suggest that the neurotoxic signs produced by PM are the consequence of MFA present in the plant leaves.