β-Asaronol, the Neuroactive Component of Acorus tatarinowii: Mitigating Seizures with Minimal Developmental Risk in Dravet Syndrome

Abstract

Developmental epileptic encephalopathies (DEEs), including Dravet syndrome (DS), require antiseizure medications (ASMs) that balance efficacy with developmental safety. There is an urgent clinical need for novel therapeutic agents that combine potent anticonvulsant activity with developmental safety. β-Asarone, an active constituent of Acorus plants, has demonstrated antiepileptic potential, but its toxicities severely limit clinical application. Notably, β-asaronol, a hydroxylated metabolite of β-asarone, may exhibit improved safety; however, its pharmacological properties and therapeutic potential remain systematically unelucidated. To evaluate the developmental safety and antiseizure efficacy of β-asaronol for pediatric refractory epilepsy, developmental toxicity, antiseizure activity, and neuroprotective effects were systematically assessed using zebrafish models (Tg vmat2:GFP, Tg lfabp:EGFP, pentylenetetrazole (PTZ)-induced seizures, and scn1lab^–/– mutants). Electrophysiology, molecular docking, and biomarker analyses elucidated mechanisms. β-Asaronol (5–150 μM) exhibited no significant developmental toxicity in zebrafish, with normal hatching rate, mortality, malformation rate, and no abnormalities in neurotoxicity or hepatotoxicity indicators. Its lethal concentration 50 (LC₅₀) value was 3.5-fold higher than that of the parent compound β-asarone. It prolonged seizure latency, suppressed PTZ-induced hyperactivity (150 μM restoring baseline locomotion), and reduced neuronal apoptosis (lactate dehydrogenase (LDH)/c-fos normalization). In scn1lab^–/– mutants, β-asaronol outperformed stiripentol and cannabidiol, reducing epileptiform discharges by about 93%. Mechanistically, β-asaronol potentiated γ-aminobutyric acid type A (GABA_A) receptor currents (EC₅₀ = 20.8 μM) via benzodiazepine-binding site interactions. β-Asaronol combines superior developmental safety with potent antiseizure efficacy, positioning it as a promising candidate for Dravet syndrome and refractory epilepsy.