Anxiolytic-like effects of acute and chronic treatment with Achillea millefolium L. extract

Ethnopharmacological relevanceAchillea millefolium L. (Asteraceae), known as yarrow (“mil folhas”), has been used as folk medicine for gastrointestinal disorders, inflammation, anxiety, and insomnia.AimTo evaluate the potential anxiolytic-like effect of hydroalcoholic extract of Achillea millefolium L. in animal models.MethodsThe present study evaluated the effects of the hydroalcoholic extract from the aerial parts of Achillea millefolium L. in mice subjected to the elevated plus-maze, marble-burying, and open-field tests. Additionally, the GABAA/benzodiazepine (BDZ) mediation of the effects of Achillea millefolium was evaluated by pretreatment with the noncompetitive GABAA receptor antagonist picrotoxin and the BDZ antagonist flumazenil and by [3H]-flunitrazepam binding to the BDZ site on the GABAA receptor.ResultsAchillea millefolium exerted anxiolytic-like effects in the elevated plus-maze and marble-burying test after acute and chronic (25 days) administration at doses that did not alter locomotor activity. This behavioral profile was similar to diazepam. The effects of Achillea millefolium in the elevated plus-maze were not altered by picrotoxin pretreatment but were partially blocked by flumazenil. Furthermore, Achillea millefolium did not induce any changes in [3H]-flunitrazepam binding.ConclusionThe results indicate that the orally administered hydroalcoholic extract of Achillea millefolium L. exerted anxiolytic-like effects that likely were not mediated by GABAA/BDZ neurotransmission and did not present tolerance after short-term, repeated administration.