No abstract

A series of 5-substituted benzo[d][1,3]dioxole derivatives was designed, synthesized, and tested for anticonvulsant activity using the maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) screens. Neurotoxicity was determined by rotarod test. In the preliminary screening, six compounds, 3a, 3c, 3d, and 4d-f, showed promising anticonvulsant activities in the MES model, and compounds 4c and 4d exhibited full protection against seizures at doses of 300 mg/kg in the scPTZ model. Among the synthesized compounds, 3c as the most active compound showed high protection against the MES-induced seizures with an ED value of 9.8 mg/kg and a TD value of 229.4 mg/kg after intraperitoneal injection into mice, thus providing compound 3c with a high protective index (TD /ED ) of 23.4 comparable to those of reference antiepileptic drugs.

Sodium channel blockers are important antiseizure drugs. Since the launch of phenobarbital in 1912, it has a development history of nearly 100 years. However, because of the confounding symptoms, complications, and complex intrinsic pathogenesis of epilepsy, the design and development of blockers specifically targeting sodium channels as antiseizure drugs are difficult and rarely reported. In this study, we designed and synthesized a series of novel benzo­[d]­isoxazole derivatives as anticonvulsants. Among them, the most potent Z-6b displayed high protection against the MES-induced seizures with an ED50 value of 20.5 mg/kg and a high protective index (TD50/ED50) of 10.3. In addition, Z-6b significantly inhibited NaV1.1 channels in patch-clamp experiments but almost did not inhibit NaV1.2, NaV1.3, and NaV1.6 channels. These findings strongly support the hypothesis that new benzo­[d]­isoxazole derivatives display anticonvulsant activity by selectively blocking voltage-gated sodium channel NaV1.1, which provides good alternatives for developing selective NaV1.1 channel blockers as antiseizure drugs in the future.

A series of 5-(o-tolyl)-1H-tetrazole derivatives were synthesized and evaluated for their anticonvulsant activities. 1-(2-Methylbenzyl)-5-(o-tolyl)-1H-tetrazole (3h) showed important anticonvulsant activity against the MES-induced seizures, as well as lower neurotoxicity with an ED value of 12.7 mg/kg and a TD value of over 500 mg/kg after intraperitoneal injection into mice, providing 3h with a high protective index (TD /ED ) of over 39.4. The achieved results prove that the distinctive compounds could be valuable as a model for future development, adaptation, and investigation to construct more active analogues.