Abstract

ANXIOLYTIC ACTIVITY OF AQUEOUS EXTRACT OF BRIDELIA MICRANTHA (HOCHST) BAILL (EUPHORBIACEAE) IN MICE EXPOSED TO CHRONIC IMMOBILIZATION STRESS

Delphine Mireille Ze Minkoulou*, Jean Pierre Omam Omam, Antoine Kavaye Kandeda, Florence Ngueguim Tsofack, Elisabeth Ngo Bum, Théophile Dimo

ABSTRACT

Anxiety disorders are a major public health concerning worldwide. The current anxiolytics are ineffectives and associated with major side effects. Thus, medicinal plants with better effects constitute source of new pharmaceutical drugs. This work aimed to assess the anxiolytic-like properties of aqueous bark extract of Bridelia micrantha on behavioral and neurochemical characteristics, using male mice subjected to chronic immobilization stress. The anxiolytic properties of B. micrantha were assessed in mice after repeated stress by immobilization. Mice received distilled water (10 ml/kg, p.o), diazepam (2 mg/kg, i.p) or B. micrantha extract (76, 152 or 305 mg/kg, p.o) one hour prior to daily exposure to stress by immobilization in the adapted plastic cone (3h/day) for 14 days. The behavioral parameters were evaluated using Elevated Plus Maze (EPM), Open Field (OF) and Hole-Board (HB) tests. The plasma levels of serotonin and corticosterone were determined by ELISA technique. Like diazepam, the extract increased (p0.001) the number of open arms entries and the time spent in open arms of the EPM. The extract elicited the increase of crossing and grooming number, and the time spent in centre of the of. On the HB, the extract increased (p< 0.001) the number of head dipping and decreased the number ofcrossing. The extract increased (p<0.001) plasma serotonin levels and decreased corticosterone levels. The chronic restraint stress-induced behavioral and neurotransmitters levels abnormalities were attenuated by the extract. These overall results suggest that aqueous bark extract of B. micrantha might have a promising therapeutic potential for stress-related disorders.

Keywords: Chronic Immobilization Stress, Anxiety, B. Micrantha, Serotonin, Corticosterone.