Ellagitannins and triterpenoids extracts of Anogeissus leiocarpus stem bark extracts: Protective effects against osteoarthritis

Abstract Osteoarthritis (OA) is a complex joint disease characterized by persistent pain. Unfortunately, current pharmacological therapies are unsatisfactory and characterized by side effects, reason why new strategies are needed. We tested the efficacy of different classes of compounds, ellagitannins and olean‐type triterpenoids, contained in Anogeissus leiocarpus extract (Combretaceae family) in comparison to ellagitannins of Castanea sativa extract in a rat model of osteoarthritis induced by the intra‐articular injection of sodium monoiodoacetate (MIA). The decoction of stem bark of A. leiocarpus AL‐DEC‐TOT (300 mg/kg; 4.8% triterpenoids; 11.0% tannins), the butanol extract AL‐BuOH‐EXT (120 mg/kg; triterpenoids 20.9%; tannins 6.4%) and its correlated aqueous residue AL‐Res‐H 2 O (300 mg/kg; triterpenoids 0.7%; tannins 8.7%) and the decoction of C. sativa , CS‐DEC‐TOT, (240 mg/kg; triterpenoids 0.65%; tannins 10.8%) were orally administered for two weeks starting from the day of the damage. Behavioural tests highlighted that all stem bark extracts of A. leiocarpus counteracted hypersensitivity development, reduced spontaneous pain, and improved motor skills. Histologically, AL‐DEC‐TOT, AL‐BuOH‐EXT and AL‐Res‐H 2 O were effective in preventing joint alterations. In conclusion, all the extracts were effective demonstrating that both olean‐type triterpenoid and ellagitannin fractions have anti‐hypersensitivity and restorative properties running the stem bark extracts of A. leiocarpus as a candidate in the treatment of OA.