Imperatorin

Pharmacology & Research

Imperatorin is a linear furanocoumarin — structurally in the psoralen family alongside bergapten and 8-MOP — concentrated in the roots and seeds of angelica (Angelica archangelica, A. dahurica, not A. sinensis/Dong Quai) and bishop’s weed (Ammi majus). Its preclinical activity is broad: anti-inflammatory/analgesic via NF-κB and MAPK suppression ^{6,7Reference 62020Anti-nociceptive and anti-inflammatory effects of imperatorin: COX-2, iNOS, NF-κB and cytokinesView study →Reference 72022Imperatorin attenuates neuroinflammation in ischemic stroke via MAPK/NF-κBView study →}, sodium-channel anticonvulsant and GABAergic anxiolytic effects ^{1,2Reference 1Luszczki JJ et al. · 2007Imperatorin enhances the protection offered by conventional antiepileptic drugs in the maximal-electroshock seizure testView study →Reference 2Wu SN et al. · 2013Imperatorin-mediated suppression of voltage-gated Na⁺ channelsView study →}, and NO/calcium-mediated vasodilation ^{10,11Reference 102009Imperatorin-induced vasodilatation is NO/endothelium-dependent (Angelica dahurica var. formosana)View study →Reference 112010Store-operated calcium entry in imperatorin-induced vasodilatation of mesenteric arteryView study →}. Two things frame it, and both are furanocoumarin-class properties that dominate the safety story: it is a UV photosensitiser and a CYP3A4/2C/2B6 inhibitor with grapefruit-type drug-interaction potential ^{16,14Reference 16Raquet N · 2014Photo-cytotoxic and photo-genotoxic activity of a furanocoumarin mixture under UVAView study →Reference 142025In vitroImperatorin/curcumin drug interactions on macitentan (CYP3A4), in vitro and in vivoView study →}. It is poorly bioavailable, and there are no human trials of the isolate.

1. Anti-inflammatory / analgesic

Imperatorin reduced nociception and inflammation in rodents with lowered COX-2, iNOS, NF-κB and cytokines ^{6Reference 62020Anti-nociceptive and anti-inflammatory effects of imperatorin: COX-2, iNOS, NF-κB and cytokinesView study →}, attenuated neuroinflammation in ischemic stroke via MAPK/NF-κB ^{7Reference 72022Imperatorin attenuates neuroinflammation in ischemic stroke via MAPK/NF-κBView study →}, suppressed allergic airway inflammation through FcεRI/TLR–MAPK/NF-κB ^{8Reference 82026Imperatorin suppresses allergic airway inflammation via FcεRI/TLR–MAPK/NF-κBView study →}, and activated PXR to attenuate DSS colitis ^{9Reference 92018Imperatorin activates PXR to attenuate DSS-induced colitisView study →}.

Gap: all animal/cell, with no isolated-compound human data and oral doses high relative to achievable plasma levels ^{6,8Reference 62020Anti-nociceptive and anti-inflammatory effects of imperatorin: COX-2, iNOS, NF-κB and cytokinesView study →Reference 82026Imperatorin suppresses allergic airway inflammation via FcεRI/TLR–MAPK/NF-κBView study →}.

2. Neuroprotective / anticonvulsant

The most-replicated imperatorin story — and the one now under tension. Imperatorin raises the maximal-electroshock seizure threshold dose-dependently ^{1Reference 1Luszczki JJ et al. · 2007Imperatorin enhances the protection offered by conventional antiepileptic drugs in the maximal-electroshock seizure testView study →} and suppresses voltage-gated Na⁺ channels ^{2Reference 2Wu SN et al. · 2013Imperatorin-mediated suppression of voltage-gated Na⁺ channelsView study →}, with anxiolytic and pro-memory effects in mice ^{3Reference 3Budzynska B et al. · 2012AnimalEffects of imperatorin on anxiety and memory in miceView study →} and relief of neuropathic pain by increasing GABAergic tone ^{4Reference 42026Imperatorin relieves neuropathic pain by increasing GABAergic toneView study →}.

Gap: a 2025 whole-A. archangelica extract study found only non-significant anticonvulsant activity ^{5Reference 5Suciu I et al. · 2025Anticonvulsant potential of Morus/Angelica/Valeriana/Passiflora extracts (non-significant for Angelica)View study →} — the isolated-compound potency does not transfer to the crude herb, the single most important honesty note on the page.

3. Vasodilatory

Imperatorin causes endothelium/NO-dependent vasodilation ^{10Reference 102009Imperatorin-induced vasodilatation is NO/endothelium-dependent (Angelica dahurica var. formosana)View study →} and relaxes mesenteric artery by inhibiting store-operated calcium entry ^{11Reference 112010Store-operated calcium entry in imperatorin-induced vasodilatation of mesenteric arteryView study →}.

Gap: rat-only, at high effective doses, and much cardiovascular work uses imperatorin derivatives rather than the native compound — do not overstate the parent ^{10,11Reference 102009Imperatorin-induced vasodilatation is NO/endothelium-dependent (Angelica dahurica var. formosana)View study →Reference 112010Store-operated calcium entry in imperatorin-induced vasodilatation of mesenteric arteryView study →}.

4. Anticancer

Imperatorin was cytotoxic against human larynx cancer and rhabdomyosarcoma cells ^{12Reference 12Grabarska A et al. · 2020Imperatorin is cytotoxic against human larynx cancer and rhabdomyosarcoma cellsView study →}.

Gap: cell lines only, with modest and formulation-dependent potency (poor free-drug exposure) and no in-vivo tumour or clinical data ^{12Reference 12Grabarska A et al. · 2020Imperatorin is cytotoxic against human larynx cancer and rhabdomyosarcoma cellsView study →}.

Mechanisms

Target / pathway	Effect	Relevant to
NF-κB / MAPK	inhibition (↓ COX-2, iNOS, TNF-α/IL-6)	anti-inflammatory/analgesic, neuroinflammation
Pregnane X receptor (PXR)	activation	anti-colitis
Voltage-gated Na⁺ channels; GABA-A receptor	suppression / positive modulation	anticonvulsant, anxiolytic
Store-operated Ca²⁺ entry; endothelial NO/eNOS	inhibition; enhancement	vasodilation
CYP3A4 / CYP2C (inhibition); CYP2B6 (mechanism-based inactivation)	↓ metabolism of co-drugs	drug-interaction risk

Pharmacokinetics

Poorly bioavailable. Imperatorin is highly lipophilic and poorly water-soluble, with low, variable oral absorption and rapid first-pass metabolism — which is why much of the literature reaches for enabling formulations (lipid microspheres, self-emulsifying systems) to raise exposure. It is extensively metabolised by hepatic CYPs, and validated assays confirm measurable but low systemic levels ^{13Reference 132015AnimalLC-MS/MS quantification of nine furanocoumarins and rat bioavailabilityView study →}. The net result: effective preclinical doses are high precisely because free-drug exposure is low — a major translational limiter across every application.

Clinical trials

There are no human trials on isolated imperatorin. Human-relevant data exist only for whole Angelica/furanocoumarin-containing preparations, where the compound is one of many constituents — and the 2025 whole-extract anticonvulsant study was animal/in-silico with a non-significant result ^{5Reference 5Suciu I et al. · 2025Anticonvulsant potential of Morus/Angelica/Valeriana/Passiflora extracts (non-significant for Angelica)View study →}, underscoring the gap between isolated-compound promise and herb-level effect.

Last checked: July 2026.

Toxicity & Safety

Imperatorin’s two real, mechanistically-grounded hazards are both furanocoumarin-class properties. (1) Phototoxicity: as a linear furanocoumarin (psoralen family) it absorbs UVA and can form DNA photoadducts — furanocoumarin mixtures are photo-cytotoxic and photo-genotoxic under UVA ^{16Reference 16Raquet N · 2014Photo-cytotoxic and photo-genotoxic activity of a furanocoumarin mixture under UVAView study →}, and furanocoumarin-rich plant contact plus sun exposure causes phytophotodermatitis (burning, blistering, lingering hyperpigmentation) ^{17Reference 17Knapp AA · 2009PhytophotodermatitisView study →}. Imperatorin is a less potent photosensitiser than bergapten or 8-MOP, but the risk is real for topical or high-dose exposure to imperatorin-rich material — advise sun caution. (2) CYP inhibition (drug interactions): this is the same enzyme-inhibition mechanism by which grapefruit furanocoumarins raise drug levels — imperatorin inhibits CYP3A4/CYP2C and altered the disposition of co-administered drugs such as macitentan ^{14Reference 142025In vitroImperatorin/curcumin drug interactions on macitentan (CYP3A4), in vitro and in vivoView study →}, and it is a mechanism-based (irreversible) inactivator of CYP2B6 ^{15Reference 152015Imperatorin is a mechanism-based inactivator of CYP2B6View study →}. Treat imperatorin-rich preparations as capable of grapefruit-type interactions with CYP3A4/2C/2B6 substrates. These two hazards justify the moderate flag (and rule out low), while the sub-8-MOP photosensitising potency keeps it below toxic.

Pregnancy & lactation

Avoid. There is no human safety data, and as a photoactive, DNA-reactive furanocoumarin with genotoxic potential under UVA and CYP-inhibitory activity, imperatorin (and imperatorin-rich angelica/Ammi preparations) should be avoided in pregnancy and lactation.

Dosage

There is no established human dose, and imperatorin is not sold as an isolated supplement. All figures are preclinical rodent doses (typically ~5–30 mg/kg oral or i.p.) that do not translate to humans, and the poor oral bioavailability makes isolated-compound self-dosing unsupportable. Human exposure occurs only incidentally via Angelica/Ammi/bergamot preparations — for those, follow the parent-herb guidance and observe the furanocoumarin sun-exposure and drug-interaction cautions.

References