Filicene obtained from Adiantumcuneatum interacts with the cholinergic, dopaminergic, glutamatergic, GABAergic, and tachykinergic systems to exert antinociceptive effect in mice

In the present study, we describe the antinociceptive effect of filicene, a triterpene isolated from Adiantumcuneatum (Adiantaceae) leaves, in several models of pain in mice. When evaluated against acetic acid-induced abdominal constrictions, filicene (10, 30 and 60 mg/kg, i.p.) produced dose-related inhibition of the number of constrictions, being several times more potent [ID50 = 9.17 (6.27–13.18) mg/kg] than acetaminophen [ID50 = 18.8 (15.7–22.6) mg/kg], diclofenac [ID50 = 12.1(9.40–15.6) mg/kg] and acetylsalicylic acid [ID50 = 24.0(13.1–43.8) mg/kg] in the same doses as those used for the standard drugs. Filicene also produced dose-related inhibition of the pain caused by capsaicin and glutamate, with mean ID50 values of 11.7 (8.51–16.0) mg/kg and < 10 mg/kg, respectively. Its antinociceptive action was significantly reversed by atropine, haloperidol, GABAA and GABAB antagonists (bicuculline and phaclofen, respectively), but was not affected by L-arginine–nitric oxide, serotonin, adrenergic and the opioid systems. Together, these results indicate that the mechanisms involved in its action are not completely understood, but seem to involve interaction with the cholinergic, dopaminergic, glutamatergic, GABAergic and tachykinergic systems.