Date Published: October 22, 2012
Publisher: Hindawi Publishing Corporation
Author(s): Harquin Simplice Foyet, David Emery Tsala, Armand Abdou Bouba, Lucian Hritcu.
The present study examined the anxiolytic and antidepressant effects of the aqueous extract of Alafia multiflora Stapf (AM) stem barks (150 and 300 mg/kg, 7 days administration) on rats and mice, using experimental paradigms of anxiety and depression. In the open field, the aqueous extract increased significantly the number of center square crossed and the time spent at the center of the field as well as the rearing time, while the grooming time was reduced significantly. In the elevated plus maze, the aqueous extract increased the time spent and the number of entries in the open arms. All these effects were also completely reversed by flumazenil, an antagonist of benzodiazepine receptors and pindolol a β-adrenoceptors blocker/5-HT 1A/1B receptor antagonist. The time spent in the light compartment, the latency time, and the number of the light-dark transitions increased significantly in the light/dark exploration test after the treatment with AM. The extract was able to reduce significantly the immobility time and increase swimming as well as climbing duration. Taken together, the present work evidenced anxiolytic effects of the aqueous extract of AM that might involve an action on benzodiazepine-type receptors and an antidepressant effect where noradrenergic mechanisms will probably play a role.
Anxiety and depressive disorders are frequent psychiatric conditions identified as the most common stress-related mood disorders causing disability and premature death. More than 20% of the adult population suffer from these conditions at some time during their life . The World Health Organization envisaged that depression will become the second leading cause of premature death or disability worldwide by the year 2020 . The complexity of daily life in modern society leads to various degrees of anxiety and depression. Mood, depression, and anxiety disorders have been found to be associated with chronic pain among medical patients in both developed and developing countries . For many years, they were considered as two different mental diseases, with the benzodiazepines used as the drugs of choice for acute anxiety states and the amine uptake inhibitors and monoamine oxidase inhibitors to treat depression. However, in the clinical practices of the treatment of anxiety disorders, benzodiazepines are now slowly replaced by antidepressants, which are not only efficacious in depression but also in the acute and chronic treatment anxiety disorders .
In the present study, the anxiolytic and antidepressant-like effects of the chronic administration of the aqueous extract of Alafia multiflora stem bark were studied in different animal models of anxiety and depression. The Alafia multiflora stem bark extract was first studied using the open field which gives a better indication of the animal’s emotional state. The administration of the plant extract and diazepam produced a significant reduction of the grooming time and an increase in the time spent at the centre of the field. Grooming behavior following exposure to stress and the increase of the time at the center of the field clearly indicate that the plant extract has anxiolytic activity. The Alafia multiflora spontaneous activities were studied by rearing and the number of line crossed. The rearing (vertical movement) is an index of the locomotor activity  while the increased number of line crossed (horizontal movement) is an indication of the central nervous system stimulant properties. The chronic administration of the aqueous extract of the Alafia multiflora stem bark significantly increased the rearing time and the number of crossings. These results taking together indicate that, in contrast to diazepam, the aqueous extract of Alafia multiflora showed anxiolytic-like effects without affecting locomotor activity or without producing central nervous depression. However, the significant decrease in the number of line crossed by animals treated with diazepam suggests a sedative effect of this drug at the dose used.