African Journal of Pharmacy and Pharmacology Vol. 4(5), pp. 263-269, May 2010 Available online http://www.academicjournals.org/ajpp ISSN 1996-0816 © 2010 Academic Journals Full Length Research Paper Antinociceptive and anti-inflammatory properties of Gunnera perpensa (Gunneraceae) Mpumelelo Nkomo 1 , Benedicta N. Nkeh-Chungag 2 *, Learnmore Kambizi 1 , Eugene Jamot Ndebia 2 and Jehu E. Iputo 2 1 Botany Department, Walter Sisulu University, PBx 1, Mthatha 5117, South Africa. 2 Department of Physiology, Faculty of Health Sciences, Walter Sisulu University, Mthatha 5117, South Africa. Accepted 16 March, 2010 Gunnera perpensa, which belongs to the Gunneraceae family, is used in folk medicine to relieve rheumatoid pain, facilitate childbirth and for healing wounds. In this study, the antinociceptive and anti- inflammatory properties of this plant extracts were evaluated using the abdominal constriction, hot- plate, formalin, hyperalgesia and fresh egg albumin-induced inflammation. The extracts were administered orally at the test doses of 150 and 200 mg/kg prior to the above-mentioned assays. Both extracts produced significant (P < 0.05, P < 0.01) inhibition of thermal nociception induced by hot plate respectively. Chemical nociception induced by intraperitoneal and sub plantar injections of acetic acid and formalin respectively, were significantly (P < 0.05, P < 0.01) reduced by the extracts in a dose independent manner. The extracts also showed significant antihyperalgesia and anti inflammatory properties (P < 0.05, P < 0.01) respectively. Our findings suggest that G. perpensa possesses both antinociceptive and anti inflammatory activity supporting its traditional use for pain management. Key words: Gunnera perpensa, hot plate, writhing, formalin, inflammation, pain. INTRODUCTION South Africa has an abundance of medicinal plants, used in the treatment of various diseases on an empirical basis (Hutchings and van Staden, 1994; Hutchings et al., 1996; Jäger et al., 1996; Salie et al., 1996; McGaw et al., 1997). The management of pain is a daily challenge in modern medicine, despite the currently available wide range of analgesics. Medicinal plants are believed to be an impor- tant source of new chemical substances with potential therapeutic effects on pain (Gupta et al., 2006; Farnsworth, 1889). Gunnera perpensa is widely used by the rural population in South Africa for the treatment of several diseases including dysmenorrhoea. Aqueous decoctions of this plant, relieve rheumatoid pain, facilitate childbirth and are believed to treat female infertility (Hutchings et al., 1996). A decoction of the rhizomes of *Corresponding author. E-mail: bnkehchungag@wsu.ac.za. Tel: +27 47 502 2794. Fax: +27 47 502 2758. Abbreviations: GPAE, Gunnera perpensa aqueous extract; GPME, Gunnera perpensa methanolic extract. G. perpensa is applied as a dressing for wounds and psoriasis (Watt and Breyer-Brandwijk, 1962, Grierson and Afolayan, 1999). Previous studies have showed that G. perpensa has both antibacterial and antioxidant properties, as well as stimulate fibroblast growth in wound healing (Steenkamp et al., 2004). Drewes et al. (2005) showed that Z-venusol, a phenylpropanoid glucoside and two new, simple, 1,4 benzoquinones isolated from G. perpensa had antibac- terial activity as well as contracted both ileal and uterine smooth muscles. However, up to date, there is no scien- tific validation of the use of this plant in the management of pain. This study investigated the analgesic and anti- inflammatory activity of aqueous and methanolic extracts of G. perpensa using several experimental animal moleds of pain to validate its traditional uses. MATERIALS AND METHODS Plant material Rhizomes of G. perpensa were collected on the 14th of August