Analgesic and anxiolytic properties of aqueous extract of bark from trunk of Diospyros mespiliformis (Ebenaceae) on arthritis induced in mice

Abstract

Background: Arthritis is an inflammatory disease that affects the joints. Patients suffering from chronic pain are anxious, which contributes to reducing the quality of life. The development of analgesic compounds with anxiolytic properties could prove to be of great interest for the treatment of chronic pain. The objective of the present study was to evaluate the analgesic and anxiolytic properties of the aqueous extract of the bark of the trunk of Diospyros mespiliformis in arthritic mice.

Methods: Arthritis was induced by injection of 1% formaline into the left hind paw of the animals. Inflammatory pain and comorbid anxiety were tested using a hotplate (55 ± 0.5 °C) and labyrinths (Dark and Light and the open arena), respectively.

Results: The aqueous extract of Diospyros mespiliformis reduced the inflammatory process by inhibiting the edema of the legs of animals to a maximum percentage of 63.63 % as well as the significant increase (p < 0.001) of the threshold of nociception at the dose of 100 mg/kg. A significant increase (p < 0.001) in the time spent in the lighted compartment alongside the decrease in the time spent in the dark environment was observed with the two-compartment maze. In the open arena the time spent in the central plaza significantly (p < 0.001) increased compared to the time spent on the edge. In addition, a significant decrease (p < 0.01) in the frequency of grooming and reaning was observed.

Conclusion: The aqueous extract of the bark of the trunk of Diospyros mespiliformis displayed beneficial effects on pain and anxiety, justifying it traditional use for the management of arthritis.

Keywords: analgesic, anxiolytic, Diospyros mespiliformis, arthritis.