Evaluation of the antinociceptive activity of extracts of Sonchus oleraceus L. in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Sonchus oleraceus L. has been used to relieve pain in Brazilian folk medicine.

AIM OF THE STUDY: Sonchus oleraceus L. has been used to relieve pain in Brazilian folk medicine. This study was conducted to establish the antinociceptive properties of hydroethanolic and dichloromethane extracts from aerial parts of Sonchus oleraceus in mice using chemical and thermal models of nociception.

MATERIALS AND METHODS: The formalin, hot plate, and tail immersion tests as well as acetic acid-induced writhing were used to investigate the antinociceptive activity in mice.

RESULTS: Given orally, the extracts at test doses of 30-300 mg/kg, produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid and subplantar formalin since decreased the number of writhing episodes and the time licking. Treatment with the extracts in the same doses produced a significant increase of the reaction time in tail immersion and in the hot plate test. The extracts administered at 300 mg/kg, p.o. had a stronger antinociceptive effect than indomethacin (5mg/kg, p.o.) and morphine (10mg/kg, p.o.).

CONCLUSION: The extracts of Sonchus oleraceus markedly demonstrated antinociceptive action in mice, which supports previous claims of its traditional use.