Antinociceptive and antiinflammatory activities of Adiantum latifolium Lam.: evidence for a role of IL-1β inhibition.

AIM OF STUDY Adiantum, one of the most widely distributed genera of the family Pteridaceae, is employed in folk medicine worldwide. Adiantum latifolium Lam. has been used in Latin American traditional medicine as anxiolytic, analgesic and antiinflammatory. The present study investigates the antinociceptive and antiinflammatory properties of the methanolic extract of Adiantum latifolium (MEA) in animal models of pain and inflammation to confirm its medicinal use. MATERIAL AND METHODS The antinociceptive and antiinflammatory activities of MEA were evaluated using the writhing, formalin, and tail-flick tests, carrageenan-induced paw edema and arachidonic acid-induced ear edema. Mice motor performance was evaluated in the rota rod test and the acute toxicity evaluated over 14 days. RESULTS Intraperitoneal (1-100mg/kg) or oral (100-400mg/kg) administration of MEA produced a dose-related inhibition of acetic acid-induced writhing in mouse. Furthermore, treatment with MEA (100mg/kg) inhibited both the early and late phases of formalin-induced hypernociception. In contrast, MEA (100mg/kg/IP) did not prevent the thermal nociception in the tail-flick test. In addition, MEA (100 and 200mg/kg/IP) inhibited important events related to the inflammatory response induced by carrageenan or arachidonic acid, namely local edema and increase in tissue interleukin-1β levels. MEA (300mg/kg/IP)-treated mice did not show any motor performance alterations. Over the study period of 14 days, there were no deaths or toxic signs recorded in the group of mice given 1000mg/kg of MEA. CONCLUSION The results demonstrate that Adiantum latifolium has antinociceptive and antiinflammatory activities, acting through the inhibition of IL-1β production.