Journal of Ethnopharmacology 85 (2003) 19–23 Evaluation of the analgesic and antiedematogenic activities of Quassia amara bark extract W. Toma a , J.S. Gracioso a , C.A. Hiruma-Lima b , F.D.P. Andrade c , W. Vilegas c , A.R.M. Souza Brito a,∗ a Departamento de Fisiologia e Biof´ ısica, Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109, CEP-13083-970, Campinas, SP, Brazil b Departamento de Fisiologia, Instituto de Biociˆ encias, Universidade Estadual Paulista, Botucatu, SP, Brazil c Departamento de Qu´ ımica Orgˆ anica, Instituto de Qu´ ımica, Universidade Estadual Paulista, Araraquara, SP, Brazil Received 1 February 2002; received in revised form 1 October 2002; accepted 4 November 2002 Abstract We evaluated the possible antiedematogenic, antinociceptive and/or sedative effects of four different extracts obtained from the bark of Quassia amara namely, 70% ethanol (70EtOH), 100% ethanol (100EtOH), dichloromethane (DCM) and hexane extracts (HEX). The oral administration (100, 250 and 500mg/kg) of these extracts did not show significant effects in any experiment. However, when administered intraperitoneally, the HEX extract decreased the paw edema induced by carrageenan, showed antinociceptive effects on the hot-plate test and on acetic acid-induced writhing, and showed sedative effects on pentobarbital-induced sleep. Naloxone did not reverse the antinociceptive effect of this extract. In conclusion, although the mechanisms are uncertain, the results demonstrated that these effects are apparently related to sedative and muscle relaxant or psychomimetic activities of the HEX extract of the plant. © 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Quassia amara; Antiedematogenic effect; Antinociceptive effect; Sedative effect 1. Introduction The medicinal use of plants is an ancient tradition, far older than the contemporary sciences of medicine, pharma- cology and chemistry. The World Health Organization has estimated that over 75% of the world’s population still relies on plant-derived medicines, usually obtained from tradi- tional healers, for its basic health-care needs (Farnsworth et al., 1985). It is believed that current analgesia-inducing drugs, such as opiates and non-steroidal anti-inflammatory drugs (NSAIDs) are not useful in all cases, because of their side effects and low potency (Ahmadiani et al., 1998). As a result, a search for other alternatives seems necessary and beneficial. The study of plants that have been traditionally used as pain killers is still a fruitful and logical research strategy in the search for new analgesic drugs (Elisabetsky et al., 1995). Quassia amara L. (Simaroubaceae), popularly known in Latin America as “Amargo”, “Hombre Grande”, “Sima- ∗ Corresponding author. Fax: +55-19-3289-6185. E-mail address: abrito@unicamp.br (A.R.M. Souza Brito). ruba”, “Pau Quassia”, “Murubá”, “Murupá” and “Quina de Caiena”, is a small tree, 2–6 m in height, which occurs in northern Brazil, Venezuela, Surinam, Colombia, Argentina, Panamá and Guiana. In Brazil, this plant is found in culti- vation from the border with Guiana to the state of Maran- hão and its wood is reputed in traditional medicine to have antimicrobial, antianemic, cytotoxic and antimalarial activ- ities, as well as being useful for the treatment of digestive disorders (Corrˆ ea, 1984). Quassia amara is classified by the Food and Drug Administration (FDA) as a narcotic drug (Duke, 1992). Previous phytochemical analyses have identified numerous compounds from Q. amara, including indole alkaloids, steroids (stigmasterol, -sitosterol and campesterol) and triterpenes (quassin and neoquassin) (Germonsén-Robineau, 1998). In view of the use of this plant in Brazilian folk medicine, the numerous chemical substances identified in Q. amara bark, and the lack of pharmacological stud- ies on the antinociceptive, antiedematogenic and sedative effects of the extracts of this plant, we evaluated the antinociceptive and antiedematogenic effects of four bark extracts of different polarities, using the hot-plate anal- gesic test and paw edema in mice, focusing on possible 0378-8741/02/$ – see front matter © 2002 Elsevier Science Ireland Ltd. All rights reserved. PII:S0378-8741(02)00334-3