TRP Modulators Based on Glycine and Mono-, Bicyclic Terpenoids – Synthesis and Pharmacological Properties

Currently, significant interest in drug development is focused on obtaining drugs that simultaneously affect various pharmacological targets and thus exhibiting combined actions. Herein we demonstrate the possibility of development of novel drugs that are able to simultaneously modulate TRP-channels and bind to glycine receptors. For this purpose esters based on mono- and bicyclic terpenoids (menthol, thymol, carvacrol, guaiacol, eugenol, borneol) and an inhibitory amino acid (glycine) were synthesized via Steglich esterification. Their anticonvulsant action was evaluated by a PTZ-induced convulsion model and analgesic effect − by pharmacological models of thermal and chemical stimuli. All studied esters were found to produce antinociceptive effects and attenuate acute pain more than the reference drug benzocaine after topical application. The present findings indicate that glycine esters of abovementioned terpenoids are not classical prodrugs and possess their own pharmacological activity. Prolonged antiseizure action of the esters was revealed at 24 h after oral administration. Moreover, orally co-administered gidazepam (1 mg/kg) and glycine esters produce synergistic seizure prevention effects.