Anti-inflammatory effects of ethanolic extract and alkamides-derived from Heliopsis longipes roots

Ethnopharmacological relevanceHeliopsis longipes (A. Gray) Blake (Asteraceae) is a broadly used species in the Mexican, Central and South American Traditional Medicine for its anaesthetic, analgesic, anti-inflammatory and anti-ulcerative properties. The ethanolic extract contains alkamides, mainly affinin (spilanthol). This family of compounds exerts an in vitro inhibitory action on the cyclooxygenase and lipoxygenase enzymes.Aim of the studyThe present study approaches the anti-inflammatory effect of the extract and its main bioactive component affinin and derived isobutyl-decanamide.Materials and methodsThe anti-inflammatory effect was evaluated through the mouse ear oedema test by means of two irritating agents, arachidonic acid (AA) and phorbol myristate acetate (PMA).ResultsHeliopsis longipes, affinin and isobutyl-decanamide displayed a marked anti-inflammatory effect on the AA model with ED50 = 0.8, 1.2 and 0.9 mg/ear, respectively. Nimesulide (1 mg/ear) was used as a reference drug. In PMA model, the extract and two alkamides also showed a dose-dependent anti-inflammatory effect with ED50 = 2.0, 1.3 and 1.1 mg/ear, respectively. Indomethacin (3 mg/ear) was used as reference drug.ConclusionsThese results could represent an important contribution to explain the anti-inflammatory ethnobotanical effects reported for Heliopsis longipes and other species containing affinin (spilanthol). For the first time the topical anti-inflammatory effects of Heliopsis longipes, affinin and isobutyl-decanamide were studied.