Background Inflammation is the most common health problem faced in life relating to a vast number of diseases. The present study evaluated the pharmacological effect of three plants (Vitex thyrsiflora, Entandrophragma cylindricum, and Anonidium mannii) commonly used in the Cameroon pharmacopeia for the management of inflammatory response. Methods The pharmacological effect was characterized by the antioxidant capacity, anti-inflammatory, analgesic, and antipyretic properties of the ethanol extracts of the three plants. Antioxidant capacity was determined using total phenolic content, total flavonoid content, hydrogen peroxide, ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical scavenging assays. Anti-inflammatory activity was evaluated in vitro by protein denaturation and hypotonic-induced hemolysis methods and in vivo by carrageenan paw edema method. Analgesic and antipyretic activities were studied in vivo using acetic acid-induced writhing and brewer's yeast-induced hyperpyrexia models. Results All selected extracts showed high phenolic (15.93-64.45 mgCAE/g) and flavonoid (336.03-1053.48 mgCAE/g) contents and high ferric reducing power (288.75-364.91 mgCAE/g). These extracts exhibited good DPPH (IC50 = 0.30-1.65 μg/mL), ABTS (IC50 = 0.52-1.90 μg/mL), and H2O2 (IC50 = 1.40-3.55 μg/mL) radical scavenging activities. All extracts inhibited protein denaturation (6.79-82.27%) and protected the erythrocyte membrane from lysis induced by hypotonic solution (18.90-88.00%). The extracts significantly reduced dose-dependent paw edema (p < 0.05), fever, and abdominal writhing (p < 0.001) especially at 400 mg/kg. Conclusions All extracts exhibited interesting antioxidant properties, as well as significant anti-inflammatory, analgesic, and antipyretic effects.
Keywords: analgesic activity; anti-inflammatory activity; antipyretic activity; ethanol extract; medicinal plants,.