The present study evaluates the anti-nociceptive and anti-inflammatory properties of the aqueous and methylene chloride/methanol (CH2Cl2 / CH3OH) extracts of the stem bark of Croton macrostachyus. The extracts administered orally at the doses of 150, 300 and 600 mg/kg were examined against pain induced by acetic acid, formalin and pressure and against inflammation induced by carragenan, histamine and formalin. Both extracts induced a significant dose-dependent (P < 0.001) reduction in the number of abdominal constrictions induced by acetic acid. The three doses of the two extracts also significantly reduced (P < 0.001) the two phases of pain induced by formalin. At the dose of 600 mg/kg, the aqueous and the CH2Cl2 / CH3OH extracts exhibited a significant analgesic activity against pressure-induced pain. The two extracts also exhibited anti-inflammatory activity, the CH2Cl2 / CH3OH extract being the most active, inhibited acute inflammation induced by carrageenan, histamine and formalin. Both extracts also significantly reduced the chronic inflammation induced by formalin. These results show that the aqueous and CH2Cl2 / CH3OH extracts of the stem bark of Croton macrostachyus possess analgesic and anti-inflammatory properties. These findings are in accordance with the traditional use of the plant and indicate that Croton macrostachyus is a potent source of analgesic and anti-inflammatory principles.

RESUME

Neoboutonia velutina. Prain is a plant used in Cameroonian ethnomedicine for the treatment of digestive disorders such as constipation. This study was conducted to evaluate the laxative properties of aqueous and methanolic extracts of N. velutina in rats. The laxative properties as mentioned by the consulted traditional healer were firstly determined, through an evaluation of fecal emission outset, number of wet defecations, water content of faeces, ions secretion, gastrointestinal motility and intestinal fluid accumulation in an acute loperamide induced-constipation and secondly by evaluating the defecation outset, defecation frequency and water content of faeces in a pre-sub-chronic treatment. The results show that the two extracts after 08 h of observation, significantly reduced the fecal emission outset at 125 mg/kg and increased the number of wet defecations except 250 mg/kg of the aqueous extract. The methanolic extract significantly increased the fecal water content compared to the control groups. Both extracts stimulated the secretion of water and ions such as K + , Na + and Cl -, leading to intraluminal retention of water and an accumulation of intestinal fluid. Finally, the pre-sub-chronic treatment of constipated animals led to significant increase of fecal water content and defecations. These extracts could have laxative properties resulting from the presence of some phytoconstituents that could stimulate the increase in the fecal water content and the number of defecation. These results therefore support the traditional use of the plant in the treatment of constipation.