Comparison of aqueous extract of Salep’s root (Dactylorhiza maculate) with ibuprofen on pain sensory thresholds using the formalin test in adult male rats.

Pain is an unpleasant feeling that usually occurs as a result of tissue injuries. Salep could have significant analgesic effects in acute and chronic pain modalities due to its glucomannan content. Considering the fact that there has not been any study on the antinociceptive effects of Salep, and considering the antioxidant and anti-inflammatory properties of the Salep root’s compounds, the aim of this study was to investigate the effect of Salep root extract on the reduction and prevention of formalin-induced pain.

In this experimental study, 56 male Wistar rats were randomly divided into 7 groups, including Control, Sham (distilled water), Ibuprofen (6 mg/kg/BW) groups and four groups receiving the aqueous extract of Salep root (80, 160, 320 and 640 mg/kg/BW). All treatments were injected intraperitoneally. Formalin test was performed 30 minutes after injection of Salep extract. Data were analyzed by one-way ANOVA and Duncan's post-test at a significance level of 0.05.

Salep at concentrations of 320 and 640 mg/kg caused a significant reduction in acute pain and at concentrations of 160, 320 and 640 mg/kg significantly decreased chronic pain. Ibuprofen also reduced acute and chronic pain induced by formalin.

This research demonstrated the dose-dependent antinociceptive effect of Salep root extract which is probably related to glucomannan and its antioxidant and anti-inflammatory properties.