Evaluation the Aqueous Leaf Extract and Solvent Fractions of Pyrenacantha staudtii Engl. (Icancinaceae) for Antidepressant and Anxiolytic-like Activities in Mice

Abstract

Background and Purpose: Pyrenacantha staudtii Engl. (Icacinaceae) is a plant used traditionally for treating blennorrhea, hernia, insomnia, intestinal pain and diarrhea in Nigeria. The aim of the present study was to screen its aqueous extract and fractions for some neuropharmacological activities. Materials and Methods: Classical behavioral tests for antidepressant-like and anxiolytic-like, and hypnotic-sedative activities were conducted using the crude aqueous extract of Pyrenacantha staudtii (CAEPS) and its solvent fractions at doses of 100, 200, and 400 mg/kg, intraperitoneally. Results: CAEPS at all doses significantly reduced the immobility time of mice in force swim test (FST) but reduced only at 400 mg/kg dose in tail suspension test (TST). The dichloromethane fraction (DCMF) and n-hexane (n-HF) did not significantly alter the results in both models. The ethanol fraction (EF) at 400 mg/kg and the ethyl acetate fraction (EAF) significantly reduced immobility time in FST and TST. CAEPS and EF at all doses, and EAF at 400 mg/kg significantly reduced the number of lines and squares crossed in open field test, while DCMF and n-HF did not. The number of head dips significantly decreased in the extract-treated groups in the hole board test. The CAEPS at 400 mg/kg and EF at 200 and 400 mg/kg doses significantly increased the time spent in the open arms of the elevated plus maze (EPM) but EAF, DCMF, and n-HF did not. CAEPS and EF at all doses and EAF at 400 mg/kg prolonged phenobarbitone-induced sleeping time while DCMF did not. Conclusion: The extract and polar fractions possess antidepressant-like, anxiolytic-like and sedative properties. This lends credence to the use of the plant in the treatment of mood disorders in Nigerian traditional medicine.