Anticonvulsant Potential of 1-Aryl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines: Insights from Strychnine and Nicotine Models in In Vivo and In Silico Studies

Abstract

Background: Epilepsy is a chronic, non-communicable brain disorder characterized by recurrent seizures. Some derivatives of 1,2,3,4-tetrahydroisoquinolines have demonstrated anticonvulsant effects. This study aims to investigate the effects of 33 derivatives of 1-aryl-1,2,3,4-tetrahydroisoquinoline on seizures induced by nicotine and strychnine. Methods: The anticonvulsant effects of 1-aryl-1,2,3,4-tetrahydroisoquinoline derivatives were evaluated in white male mice. Convulsant agents were administered subcutaneously at doses of 10.0 mg/kg for nicotine and 1.5 mg/kg for strychnine, 60 min after the oral administration of the test compounds at doses ranging from 0.1 to 10 mg/kg. The onset time, duration of tremors and seizures, and survival rate of the animals were recorded. The docking studies were conducted for 32 tested compounds targeting the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor (PDB ID: 1FTL). Furthermore, a predictive ADMET study was conducted to evaluate the pharmacokinetic and toxicity profiles of the compounds. Results: Compounds 20 and 25 exhibited the highest activity against strychnine-induced seizures. When evaluating the effects of 1-aryl-1,2,3,4-tetrahydroisoquinolines and reference drugs on the tremorogenic and convulsive actions of nicotine at doses of 0.1–5 mg/kg, compounds 3, 6, 8, 14, 16, 25, 27, 29, 30, 31, and 34 demonstrated comparable activity to the reference drugs. The docking results targeting AMPA (PDB ID: 1FTL) revealed comparable binding interactions for most of the compounds, with a (−)C-Docker interaction energy range of 33.82–45.41 Kcal/mol, compared to that of the ligand (41.60 Kcal/mol). The structural requirements of the studied scaffold were analyzed to identify the essential pharmacophoric features for anticonvulsant activity. Furthermore, a predictive ADMET study was conducted to evaluate the pharmacokinetic and toxicity profiles of the compounds. Conclusions: Certain derivatives of 1,2,3,4-tetrahydroisoquinolines may serve as potential anticonvulsant agents for epilepsy.