Antinociceptive effect of some amaryllidaceae plants in mice

The antinociceptive effects of ethanolic extracts of Pancratium maritimum L., Narcissus tazetta subspecies tazetta and Leucojum aestivum L. bulbs have been investigated in mice using the p-benzoquinone-induced abdominal constriction and hot-plate tests. In the p-benzoquinone-induced abdominal constriction test the ethanolic extracts of P. maritimum (300, 600 or 1200 mg kg-1, s.c.) and N. tazetta subsp. tazetta (5, 50, 100 or 200 mg kg-1, s.c.) caused dose-dependent inhibition of abdominal constrictions whereas a fluctuating response was obtained from ethanolic extracts of L aestivum (2.5-500 mg kg-1, s.c.). In the hot-plate test P. maritimum and L. aestivum caused a significant increase of latency only at the highest concentrations used (1200 mg kg-1 and 500 mg kg-1, i.p., respectively). However, at these concentrations they also caused significant toxic effects. In contrast with P. maritimum and L. aestivum, N. tazetta subsp. tazetta (5-500 mg kg-1, i.p.) extracts had no antinociceptive effect in this test. These findings indicate that the antinociceptive effect of Amaryllidaceae plants differs depending on the model of nociception investigated.