Abstract

The anti-inflammatory and anti-nociceptive activities of the root extract ofElephantorrhiza elephantina (Burch.) Skeels (Fabaceae) were investigated using wistar rats. The extract was administered intraperitoneally (i.p) to rats at graded doses of 50, 100 and 200 mg/kg BWt.  Carrageenan and Histamine were injected into rat paws sub-plantar to induce paw oedema, while acetic acid and formalin were injected i.p to induce pain. Indomethacin (10 mg/kg) was used as reference drug, whereas the vehicle [0.9% normal saline in 3% tween 80 (2 ml/kg)] was used as negative control. Acute toxicity was tested in rats at doses of 200, 400, 800 and 1600 mg/kg BWt. Compared to control, the aqueous extract of E. elephantina at all doses investigated significantly (P < 0.05) reduced the formation of oedema induced by Carrageenan and Histamine. The extract also caused a significant (P < 0.05) reduction in writhings in the acetic acid test and licking time in the formalin test. The rats did not show any signs of acute toxicity. The study revealed the anti-inflammatory and anti-nociceptive activities of the aqueous extract of E. elephantina,which may be due to the presence of phytochemical constituents such as tannins and flavonoids. The acute toxicity test showed that the plant is relatively safe to use.

Key words: Inflammation, pain, aqueous extract, acute toxicity.