Abstract

Securinega virosa is a commonly used medicinal plant in West Africa sub-region for the management of painful and inflammatory conditions. In the present study, the analgesic and anti-inflammatory activities of methanol root bark extract of S. virosa (SV) were investigated. The anti-inflammatory activity was evaluated using carrageenan-induced rat paw oedema while analgesic activity was tested by acetic acid-induced writhing response and hot plate tests in Swiss albino mice, and formalin-induced pain in Wistar rats. The methanolic root bark extract of SV (6.25 - 25 mg·kg^-1 body weight, i.p.) significantly (P < 0.05) inhibited acetic acid-induced abdominal constrictions and attenuated the neurogenic pain (phase 2) induced by formalin. The extract also significantly (P < 0.01) prolonged the reaction latency to pain thermally-induced in mice by the hot plate. The extract at the doses (6.25, 12.5 and 25 mg·kg^-1) tested afforded 12, 52 and 52% inhibition of paw oedema respectively at the end of third hour. The intraperitoneal and oral LD₅₀ values in mice were found to be 774.6 and greater than 5000 mg·kg^-1respectively, while the preliminary phytochemical screening reveals the presence of alkaloid, tannins, saponins and flavonoids. The relatively high oral median lethal dose (> 5000 mg·kg^-1) suggests that the extract is relatively non toxic when taken orally. The present study indicates that SV has significant anti-inflammatory and analgesic properties and lend pharmacological support to suggested folkloric uses of the plant in the management of painful and inflammatory conditions.

Key words:  Securinega virosa, analgesia, writhing, anti-inflammation, carrageenan.