Analgesic and antiinflammatory activities of Erigeron floribundus

This study was intended to evaluate the analgesic and antiinflammatory activities of an aqueous extract of Erigeron floribundus (H.B. & K) or (syn": Conyza sumatrensis (Retz) E.K. Walker) (Asteraceae). Phytochemical analysis was carried out using standard methodologies. The analgesic investigations were carried out against two types of noxious stimuli, chemical (formalin-induced pain and acetic acid-induced writhing) and thermal (hotplate and tail immersion tests). The effects following aspirin and naloxone pretreatments were also studied. For the antiinflammatory activities, the carrageenan-induced oedema of the hindpaw of rats was used and the paw volume measured plethysmometrically from 0 to 24 h after injection. This was compared to a standard drug indomethacin (10 mg/kg). The results were subjected to statistical analysis. The plant had saponins, flavonoids, glycosides, alkaloids, oils, phenols and tannins and significantly increased the reaction time of hotplate and immersion tests. It decreased the writhings of acetic acid-induced abdominal contractions and lickings of formalin-induced pain. Aspirin had no effect on hotplate and tail immersion tests but showed an effect on writhing test. These results showed that the plant had both central and peripheral acting effects and this was confirmed by its effect on both phases of formalin-induced pain. The extract also significantly decreased the rat paw oedema volume at 50 mg/kg and above. In conclusion, Erigeron floribundus has central and peripheral analgesic properties as well as antiinflammatory activities.