Effects of Extract of Arrabidaea chica Verlot on an Experimental Model of Osteoarthritis.

The aim of this study was to analyze the analgesic potential of Arrabidaea chica extract (EHA) as an alternative to osteoarthritis (OA) treatment. Thus, the extract was initially evaluated by the cyclooxygenase inhibition test. The analgesic effect of the extract, in vivo, was also verified in a model of OA induced by sodium monoiodoacetate (2 mg). EHA was administered to rats at doses of 50, 150, and 450 mg/kg between 3 and 25 days after OA induction. The animals were clinically evaluated every 7 days, euthanized at 29 days, and the liver, spleen, kidney and knee collected for histopathological analysis. The chemical composition of EHA was identified by HPLC-MS and the identified compounds submitted to molecular docking study. The results showed that the extract promoted cyclooxygenase inhibition and produced significant improvements in disability, motor activity, hyperalgesia, and OA-induced allodynia parameters, in addition to improvements in the radiological condition of the knees (but not observed in the histopathological study). Chemically the extract is rich in flavonoids. Among them, we evidence that amentoflavone showed very favorable interactions with the enzyme COX-2 in the in silico analysis. Thus, it is concluded that A. chica has important analgesic properties for the treatment of OA.