Abstract

Our interest has been centered on flavonol glycosides from Croton Menthodorus (Euphorbiaceae) and Aristeguietia discolor (Asteraceae). In this respect, the effect of flavonol glycosides from Croton Menthodorus (Euphorbiaceae) and Aristeguietia discolor (Asteraceae) was investigated on the naloxone-precipitated withdrawal contracture of the acute morphine-dependent guinea-pig ileum in vitro. Furthermore, the effect of these flavonol glycosides was also considered on DAGO (highly selective μ-agonist) and U50-488H (highly selective k-agonist) withdrawal to test whether the possible interaction of flavonol glycosides on opioid withdrawal involves μ- and/or k-opioid receptors. Flavonol glycosides from Croton Menthodorus (1x10-5 , 5x10-5 and 1x10-4 M) and from Aristeguietia discolor (1x10-7-1x10-6-1x10-5 M) before or after the opioid agonists were able to both prevent and reverse the naloxone-induced contracture after exposure to μ (morphine and DAGO) or k (U50-488H) opiate agonists in a concentration-dependent fascion. Both acetylcholine response and electrical stimulation were reduced by flavonol glycosides treatment as well as the final opiate withdrawal was still reduced. The results of the present study indicate that flavonol glycosides were able to produce significant influence on the opiate withdrawal in vitro and these compounds were able to exert their effects both at μ and k opioid agonists.

Keywords: Flavonol glycosides, croton menthodorus, aristeguietia discolor, opiate withdrawal, guinea pig ileum