Anti-inflammatory and anti-arthritic effects of methanol extract of the stem bark of Boswellia dalzielii Hutch (Burseraceae) in rats

Boswellia dalzielii is a tall tree (more than 13 m high) that produces aromatic white flowers. This plant is commonly used in indigenous medicine across Africa against diarrhea, malaria, vomiting, inflammation and arthritis. The present study focuses on the anti-inflammatory and anti-arthritis potential of methanol extract of Boswellia dalzielii (BDME). Anti-inflammatory activity was evaluated in inflammatory models induced by carrageenan, arachidonic acid, histamine, serotonin, prostaglandin and bradykinin. Anti-arthritis activity was measured using complete Freund’s adjuvant model. Intracellular and extracellular ROS production and proliferation of T-cells were evaluated using chemiluminescence and liquid scintillation counter techniques, respectively. TNF-α and IL-1β production were assessed using ELISA and MTT assay performed for cytotoxicity. BDME revealed a significant anti-inflammatory effect by preventing the development of edema caused by carrageenan, arachidonic acid, histamine, serotonin, prostaglandin and bradykinin. For anti-arthritic properties of BDME, the results showed a significant reduction of the joint diameter and a decrease in pain in the treated animals. The extract also showed a noticeable systemic effect, maintaining the values of the evaluated parameters close to normal in treated rats with an inhibition of joint destruction as shown in histopathological analysis. Furthermore, BDME exhibited significant inhibition of extracellular and intracellular ROS production. Still, the extract displayed significant inhibitory activity on T-cell proliferation as well as a reduced production of TNF-α and IL-1β. Boswellia dalzielii could be considered as a promising tract in the prevention and/or management of inflammatory diseases.