Prophylactic or therapeutic administration of Holarrhena floribunda hydro ethanol extract suppresses Complete Freund’s Adjuvant-induced arthritis in Sprague-Dawley rats    

Abstract

Ethnopharmacological relevance In Ghanaian folk medicine, Holarrhena floribunda has anecdotal use for the treatment of inflammatory conditions. A hydro ethanol extract of the stem bark has previously been shown to be effective in the management of acute inflammation and anaphylaxis in rodents.Aim of the study This study was aimed at evaluating the usefulness of H. floribunda stem bark hydro ethanol extract (HFE) for the management of chronic inflammation in a murine model.Materials and Methods Anti-arthritic effect of the extract was evaluated using Complete Freund’s Adjuvant-induced arthritis in male Sprague-Dawley rats. Using both prophylactic and therapeutic treatment models, parameters assessed included oedema, serology of inflammatory response, radiology, bone tissue histology and haematology. Data were analysed by ANOVA followed by Tukey’s multiple comparisons post hoc test.Results HFE at 50–500 mg/kg dose-dependently [P ≥ 0.0354 (prophylactic) and P ≥ 0.0001 (therapeutic)] inhibited swelling of the injected paw upon prophylactic [≤ 81.26 % (P < 0.0001)] or therapeutic [≤ 67.92 % (P < 0.01)] administration — and prevented spread of arthritis to the contralateral paw. Inflammation alleviation activity of HFE was further demonstrated by decrease in arthritis score, radiologic score and erythrocyte sedimentation rate. HFE at all doses significantly reduced serum IL-1α (P < 0.0197), and 500 mg/kg HFE reduced serum IL-6 (P = 0.0032). In contrast, serum concentrations of IL-10, protein kinase A and cyclic adenosine monophosphate were enhanced (P ≤ 0.0436). HFE consistently showed better prophylactic activity than when administered therapeutically.Conclusions The data demonstrate that HFE suppresses CFA-induced arthritis and modulates regulators of inflammation; including IL-1α, -6 and -10 which also play mediatory roles in several immune response pathways. These make HFE a strong candidate for development as an agent for management and modulation of inflammation and the inflammatory response, including immune response-related adverse events such as seen in severe COVID-19.