Metabolomic navigated Citrus waste repurposing to restore amino acids disorder in neural lesion

•Citrus waste is a rich source of limonoids.•It was found that limonin showed neuroprotective effect on epilepsy for the first time.•Limonin can relieve nerve damage by restoring the disorder of amino acids.•TPH2 could be a potential target for limonin to exert a neuroprotective effect.•Limonin as a natural dietary additive has broad application prospects.