Neuropharmacological Assessment of an Aqueous Bark Extract of Antiaris toxicaria (Pers.) Lesch. (Moraceae) in Rodents

Antiaris toxicaria is a plant traditionally used in Ghana for the treatment of various neurological conditions such as epilepsy and pain. This present study therefore seeks to screen for the neuropharmacological activities of the aqueous extract of Antiaris toxicaria (AAE) stem bark. The effect of Antiaris extract on pentobarbital-induced sleeping time, tail immersion test, spontaneous locomotor activity, motor coordination, PTZ-induced convulsions as well as the Irwin test was investigated. The extract produced analgesia and Straub tail at (300-3000 mg kg^-1) in the Irwin test suggestive of a morphine-like action. These effects were absent after 24 h. No deaths were recorded in the test estimating the LD₅₀ to be above 3000 mg kg^-1. Spontaneous locomotor activity of the mice in the activity meter test was decreased significantly (p<0.01, F_{4, 20} = 26.61) by the extract at 100 mg kg^-1 but increased at 300-3000 mg kg^-1. It however showed no impairment on motor coordination in the beam traversal test. The extract potentiated duration of sleeping time in the pentobarbitone interaction test and showed susceptibility to metabolism by hepatic enzymes. Analgesic properties were also further confirmed in the tail withdrawal test while it inhibited PTZ-induced convulsions. Thus, Antiaris may be a potential source for novel drug discovery in the field of neuropsychiatric research.