Exploring the antinociceptive effect of taraxasterol in mice: Possible mechanisms

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.

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.

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.

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.