Determination of toxicity in rabbits and corresponding detection of monofluoroacetate in four Palicourea (Rubiaceae) species from the Amazonas state, Brazil.

Numerous monofluoroacetate (MFA)-containing plants in Brazil cause sudden death syndrome precipitated by exercise in livestock, which is characterized by loss of balance, ataxia, labored breathing, muscle tremors, and recumbence leading to death. Four species of Palicourea collected at six farms were tested for the presence of MFA and their toxicity to rabbits. Palicourea longiflora and Palicourea barraensis contained MFA and caused sudden death in the rabbits. Palicourea croceoides and Palicourea nitidella did not contain MFA and were not toxic to rabbits. P. longiflora and P. barraensis were collected at three farms with a history of sudden death in their cattle. This is the first report of toxicity in regard to these two species.