Selaginellaceae Willk. is a distinctive family that includes the genus Selaginella, which is found worldwide and comprises approximately 700  to 750 species . Approximately 270 species of Selaginella are found in America, and the genus is widely distributed throughout America, Africa and Europe. In America, Selaginella can be found from northern Alaska east to Greenland, and south as far as Mendoza and Buenos Aires in Argentina. Selaginella are best represented in the Amazon basin, with 31 species known to grow in that region . Members of the Selaginellaceae family are mostly terrestrial, herbaceous and perennial plants and vary greatly in size, some small species have stems approximately 3 cm long, while larger species have stems 50 cm to approximately 1 m long, but under 2 cm tall. Although the Selaginellaceae family has a nearly worldwide distribution, it is not economically significant .
Several species of Selaginella are used in traditional medicine in various countries in the treatment of a variety of diseases such as skin diseases , gastritis , urinary tract infections , diabetes , hepatitis , cancer and cardiovascular problems . Extracts from some species of Selaginella have demonstrated anti-inflammatory , anti-spasmodic , cytotoxic, imunnostimulant, RNA reverse transcriptase inhibitory agents , anti-mutagenic , anti-metastatic activity  and anti-hyperglycemic activities .
Previous studies involving some species of Selaginella revealed that this genus is a rich source of steroids , biflavonoids , alkaloids , secolignans , neolignans and caffeoyl derivatives . Other compounds, such as alkaloidal glycosides, phenylpropanones and lignans, were also reported in some Selaginella species [20, 21].
Selaginella convoluta is a medicinal plant found in northeastern Brazil commonly known as “jericó”, “mão-de-sapo” and “mão-fechada”. S. convoluta is used in folk medicine as an antidepressant [22, 23], aphrodisiac, diuretic, in the treatment of amenorrhea , coughing, bleeding, increases female fertility  as well as analgesic and anti-inflammatory .
In our continuing search of the Brazilian Caatinga for medicinal plants to combine biodiversity conservation with drug discovery, we have previously demonstrated the antinociceptive effects of the ethanolic extract of Amburana cearensis in mice , and anti-ulcer activity of ethanolic extract of Encholirium spectabile in rodents .
To date, there are no reports on the antinociceptive activity of S. convoluta. Given the extensive use of this plant in the semi-arid region of Brazil to treat pain and inflammation, the aim of this study was to evaluate the antinociceptive activity of the ethanolic extract from S. convoluta in experimental models of pain in mice.