Evaluation of the central depressor effects of the ethanolic extract of the leaves of Synadenium umbellatum Pax. and its fractions in Swiss mice

Synadenium umbellatum Pax. (Euphorbiacea) is a native plant from tropical Africa known as "cola-nota", "avelos", "cancerola", "milagrosa", among others. The plant is used by Brazilian folks for having anti-inflammatory and analgesic properties, among others. It was evaluated the depressor effects over the central nervous system (CNS) of the ethanolic extract of the leaves of Synadenium umbellatum (EES) and its fractions - hexane (HF), chloroformic (CF) and methanol/water fractions (MF). Several tests were used in Swiss mice (Mus musculus), among them, barbiturate-induced sleep, open field and rota-rod test. The EES was tested at 25, 50 and 100 mg/kg doses, while the HF was tested at 10mg/kg dose, the CF at 20 mg/kg dose and the MF at 25 mg/kg dose. The EES and the HF and the CF fractions, but not the MF, have presented a possible depressor effect over the CNS once they were able to increase the stop time and decrease the number of fecal boli on the openfield, besides they were able to potencialize the barbiturate-induced sleep. The rota-rod test showed that the EES and the fractions were not able to cause motor incoordination or muscle relax. Therefore, we conclude that Synadenium umbellatum Pax. have a possible depressor effect over the CNS.