Vol. 8(1), pp. 68-76, 3 January, 2014 DOI: 10.5897/JMPR2013.5085 ISSN 1996-0875 ©2014 Academic Journals http://www.academicjournals.org/JMPR Journal of Medicinal Plants Research Full Length Research Paper Antinociceptive effects of Maytenus imbricata Mart. ex. Reissek (Celastraceae) root extract and its tingenone constituent Clarice de Carvalho Veloso 1 , Vanessa Gregório Rodrigues 2 , Adolfo de Oliveira Azevedo 1 , Cristina da Costa Oliveira 1 , Lindisley Ferreira Gomides 1 , Lucienir Pains Duarte 2 , Igor Dimitri Duarte 1 , Andre Klein 1 and Andrea de Castro Perez 1 * 1 Department of Pharmacology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. 2 Department of Chemistry, Institute of Exact Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. Accepted 3 December, 2013 Plants belonging to the genus Maytenus (Celastraceae) are routinely used in folk medicine for the treatment of pain and inflammatory diseases. The aim of this study was to assess the in vivo anti- inflammatory and anti-nociceptive effects of the root extracts and tingenone, a natural triterpene, from Maytenus imbricata Mart. ex. Reissek. Oral pre-treatment with methanol extract (ME), ethyl acetate extract (EAE) (both 100 to 1000 mg/kg) and tingenone (5.3, 15.9 and 53 mg/kg) significantly reduced the licking time in the second phase of the formalin test. Hexane/ethyl ether (1:1) extract (HEE) reduced the licking time in both phases of the formalin test and inhibited carrageenan-induced edema formation in mice. These results show that the three extracts and tingenone had significant anti-nociceptive effects in the second phase of the chemical behavioral model of nociception. Therefore, M. imbricata root extracts and tingenone, a natural quinone-methide triterpene, constitute an attractive alternative to relieve pain. Key words: Painful disorders, antinociception, Maytenus imbricate, triterpenes, tingenone. INTRODUCTION The identification of molecular components responsible for pain has led to major advances in understanding pain and developing new pharmacological tools for its treatment (Woolf, 2004). Medicinal plants constitute an alternative therapeutic approach for the treatment of painful inflammatory disorders, because they are potential sources of phytopharmaceuticals, such as flavo- noids, phytosterols, triterpenoids and other constituents. It has been demonstrated that these components inhibit the molecular targets of pro-inflammatory mediators (Iwalewa et al., 2007). The Celastraceae family comprises approximately 98 genera and 1210 species throughout the tropical and subtropical regions of the world (Simmons et al., 2008) and has been widely used in folk medicine for the treatment of inflammatory diseases, such as stomach complaints, fever, rheumatoid arthritis and cancer (Spivey et al., 2002). Maytenus is a genus of this family, and its *Corresponding author. E-mail: acp@icb.ufmg.br. Tel: +0055 31 34092721.