Antinociceptive activity of puberulin and choisyine from ethanol extract of Choisya ternata Kunth var. Sundance.

Choisya ternata Kunth variety Sundance (CTS) is a plant used in traditional medicine in North America, especially in Mexico. The present study evaluated the antinociceptive activity of the crude ethanolic extract of CTS leaves and tested its isolated compounds puberulin (Pu) and choisyine (Ch). An antinociceptive effect was observed after treatment with CTS extract and the isolated compounds Pu and Ch. Mice orally pre-treated with CTS extract (10, 30 or 100 mg/kg), Pu or Ch (0.3, 1 or 3 mg/kg) were less sensitive to chemical and thermal algesic agents in different animal models (formalin-, glutamate- and capsaicin-induced licking response tests and hot plate test). In addition, an antagonist of the opioid receptor was able to reverse the antinociceptive effect observed for the CTS extract and the isolated substance Ch, but it did not inhibit the effect of Pu. The cholinergic pathway was found to be involved in this antinociceptive effect for the CTS extract and Ch but has no participation in the Pu antinociceptive activity.