Exploring the antinociceptive effect of taraxasterol in mice: Possible mechanisms.

Abstract

Objectives: Taraxasterol is the active ingredient of Taraxacum officinale which has been used in traditional medicine for its several therapeutic effects. This study aims first to evaluate the potential spinal/supraspinal and peripheral/visceral antinociceptive effect of taraxasterol and then to investigate the contribution of GABAergic, opioidergic systems, and K_ATP channels to its antinociceptive effect.

Methods: The antinociceptive activity of taraxasterol (2.5, 5, and 10 mg/kg i.p.) was investigated with hot-plate, tail-immersion, and acetic acid-induced abdominal writhing tests (for supraspinal, spinal, peripheral/visceral pain evaluation, respectively) in BALB/c male mice, and percentage of possible maximum effect (MPE%) values were calculated. Mechanism of action studies were performed by pre-administering bicuculline, naloxone, and glibenclamide.

Results: Taraxasterol increased the MPE% values in hot-plate and tail-immersion tests at 2.5, 5, and 10 mg/kg doses (P < 0.001) and decreased the mean number of writhes at 10 mg/kg in the abdominal writhing test (P < 0.05). Naloxone and bicuculline pre-administration reversed the antinociceptive effect of taraxasterol in hot-plate and tail-immersion tests and it had no effect in the abdominal writhing test. Pre-administration of glibenclamide reversed the antinociceptive effect of taraxasterol in all tests.

Conclusion: Our study is the first to show the involvement of GABAergic and opioidergic systems in the antinociceptive effect of taraxasterol in supraspinal and spinal pain tests, and K_ATP channels in tests evaluating supraspinal, spinal, and peripheral pain pathways. Taraxasterol is a potential new herbal medicine that can be used for pain control.