Analgesic, anti-inflammatory and anti-arthritic properties of aqueous and methanolic stem bark extracts from Nauclea pobeguinii (Rubiacee) in rats.

Background Nauclea pobeguinii is a plant species found in the centre region of Cameroon. The stem bark of this plant is traditionally used to ease pain and cure inflammation. Method This study was undertaken to evaluate the effects of doses 150 and 300 mg/kg of the aqueous and methanolic stem bark extracts from Nauclea pobeguinii on acute pain, acute and chronic inflammation induced by formalin and arthritis induced by zymosan A in rats. Oxidative stress parameters such as catalase, malondialdehyde and nitric oxide were measured in rats subjected to chronic inflammation. The standard used was diclofenac at 5 mg/kg. Results Aqueous extract as well as methanolic extract of Nauclea pobeguinii led to a significant reduction in the second phase of formalin induced pain with 54.22 and 48.02% of inhibition percentage, respectively. The formalin-induced inflammatory oedema was reduced by both extracts, and this effect remains significant until the tenth day of treatment. Equally, extracts significantly increased the catalase activity and inhibited the production of malondialdehyde (MDA) in serum, brain and spinal cord and NO reduction only in serum. Both extracts significantly reduced the articular oedema induced by zymosan A for 6 h and for 5 days. Furthermore, the histological study of the articulations shows a non-altered synovial membrane and a small cartilage in all treated animals versus negative control group. Conclusions From these results, it can be concluded that pain, inflammation and arthritic healing activities of both stem bark extracts were expressed in rats and could conciliate the use of this vegetable by traditional African healers.