Abstract

Distichoselinum tenuifolium (EODT) in Portugal is widespread in the province of Algarve-S Portugal, and it is traditionally used in the treatment of contact dermatitis and skin infections. The acetic acid-induced writhing, hot-plate and formalin tests were utilized for analgesic activity, and the exploratory activity of the rats was observed in an open-field and rota rod tests. The treatment with EODT (p.o) has decreased the writhing induced by acetic acid produced in a dose-dependent manner (r = 0.997). The ED₅₀ was determined as 55.0 mg/kg. In the acute toxicity assay, no deaths were observed during the 72h period. In the hot-plate test, when EODT was administered at 55.0 mg/kg (p.o) there was a significant increase (p < 0.05) in latency time at all time of observations. The EODT reduced the licking time at both first and second phase (p < 0.05) in the formalin test. In the open field test, the EODT inhibited the locomotor activity. The rota-rod assay has shown that the oil has decreased significantly the time spent on the bar in the group treated with EODT after 60 and 90 min. This result has proved that oil has a significant effect on the central nervous system as a depressive agent. Moreover, its activity diminishes the motor activity as well as pain threshold.

Key words: Essential oil, Distichoselinum tenuifolium, apiaceae, analgesic, central nervous system, behavioral assays.