Osthole

Pharmacology & Research

Osthole (7-methoxy-8-isopentenyloxycoumarin) is a simple prenylated coumarin — the dominant active molecule in the seed of Cnidium monnieri (she chuang zi), and a minor constituent of Angelica and other members of the carrot family. It has one of the broadest preclinical literatures of any single coumarin: isolated osthole shows osteogenic, neuroprotective, anti-inflammatory/anti-asthmatic, hepatoprotective, anticancer, and glucose-lowering activity across cell and rodent models ^{1Reference 1Lin H et al. · 2024ReviewOsthole, a Coumarin from Cnidium monnieri: A Review on Its Pharmacology, Pharmacokinetics, Safety, and Innovative Drug Delivery Platforms — reviewView study →2Reference 2Zhang ZR et al. · 2015ReviewOsthole: A Review on Its Bioactivities, Pharmacological Properties, and Potential as Alternative Medicine — reviewView study →}. The catch runs through all of it: osthole is highly lipophilic and poorly water-soluble, its oral bioavailability is low and its half-life short ^{12Reference 12Sun C et al. · 2018AnimalPreparation and Pharmacokinetics Evaluation of Solid Self-Microemulsifying Drug Delivery System (S-SMEDDS) of Osthole — rat pharmacokinetic animal modelView study →14Reference 14Luo DD et al. · 2017AnimalDifferent effects of (+)-borneol and (−)-borneol on the pharmacokinetics of osthole in rats following oral administration — rat pharmacokinetic animal modelView study →}, and not a single one of these effects has been tested as the isolated molecule in a human trial. The whole-seed Cnidium extract is used traditionally, but a whole-plant result is not a molecule result.

1. Bone / osteoporosis

The strongest single line. In osteoblast cultures, isolated osthole stimulated differentiation and bone-nodule formation by activating β-catenin and BMP-2 signalling; genetic deletion of either β-catenin or Bmp2 abolished the effect, placing osthole squarely on the canonical Wnt/β-catenin–BMP anabolic axis ^{3Reference 3Tang DZ et al. · 2010In vitroOsthole stimulates osteoblast differentiation and bone formation by activation of β-catenin–BMP signaling — in vitro and ovariectomised-rat in vivo animal modelView study →}. In vivo, osthole given to ovariectomised rats largely prevented the expected bone loss, improving microarchitecture, histomorphometry and biomechanical strength — an estrogen-deficiency (post-menopausal) model of osteoporosis ^{3Reference 3Tang DZ et al. · 2010In vitroOsthole stimulates osteoblast differentiation and bone formation by activation of β-catenin–BMP signaling — in vitro and ovariectomised-rat in vivo animal modelView study →}.

Gap: the pivotal in-vivo work is a single rat model; there is no human dosing, and osthole’s poor oral bioavailability makes translating an anabolic bone dose to people non-trivial.

2. Neuroprotection

Isolated osthole is protective across Alzheimer’s-type models. In APP-expressing neural stem cells and APP/PS1 transgenic mice, osthole upregulated miR-9, promoted differentiation into neurons and rescued hippocampal-neuron function and cognition ^{4Reference 4Li SH et al. · 2017In vitroOsthole Stimulated Neural Stem Cells Differentiation into Neurons in an Alzheimer’s Disease Cell Model via Upregulation of MicroRNA-9 and Rescued Hippocampal Neurons in APP/PS1 Transgenic Mice — in vitro and mouse modelView study →}. Broader reviews catalogue antioxidant, anti-apoptotic and amyloid-lowering actions (via BACE1/miR-107 and Nrf2 pathways) in similar models ^{1Reference 1Lin H et al. · 2024ReviewOsthole, a Coumarin from Cnidium monnieri: A Review on Its Pharmacology, Pharmacokinetics, Safety, and Innovative Drug Delivery Platforms — reviewView study →2Reference 2Zhang ZR et al. · 2015ReviewOsthole: A Review on Its Bioactivities, Pharmacological Properties, and Potential as Alternative Medicine — reviewView study →}.

Gap: all cell/rodent; osthole’s brain penetration is modest, which is precisely why much of this literature bolts on absorption enhancers (borneol, intranasal nanoemulsions) ^{14Reference 14Luo DD et al. · 2017AnimalDifferent effects of (+)-borneol and (−)-borneol on the pharmacokinetics of osthole in rats following oral administration — rat pharmacokinetic animal modelView study →} rather than relying on plain oral dosing. No human cognitive data.

3. Asthma / airway inflammation

Among the better-mechanised signals. Isolated osthole relaxes airway smooth muscle by inhibiting phosphodiesterase-4D (PDE4D), amplifying cAMP/PKA signalling; a co-crystal structure showed osthole bound in the PDE4D catalytic site, blocking cAMP hydrolysis, and it improved lung function in asthmatic mice ^{5Reference 5Wang S et al. · 2020In vitroAirway relaxation mechanisms and structural basis of osthole for improving lung function in asthma — in vitro, structural, and mouse modelView study →}. A separate ovalbumin-challenge mouse study found osthole attenuated lung inflammation by suppressing IL-33/ST2 signalling ^{6Reference 6Yang Q et al. · 2020AnimalOsthole attenuates ovalbumin-induced lung inflammation via the inhibition of IL-33/ST2 signaling in asthmatic mice — mouse modelView study →}.

Gap: rodent airway models and structural biology only; no inhaled or oral human trial, and systemic exposure is limited by the same bioavailability problem.

4. Fatty liver / metabolic

Isolated osthole improves lipid handling. In a rat steatohepatitis model it cut hepatic triglycerides and free fatty acids and lowered the steatohepatitis score, effects reversed by PPARα/γ antagonists — implicating PPAR-driven lipid metabolism ^{7Reference 7Zhao X et al. · 2018AnimalPPARα/γ antagonists reverse the ameliorative effects of osthole on hepatic lipid metabolism and inflammatory response in steatohepatitic rats — rat in vivo animal modelView study →}. In hyperlipidaemic fatty-liver rats it reduced hepatic lipid accumulation ^{8Reference 8Zhang Y et al. · 2007AnimalTherapeutic effect of osthole on hyperlipidemic fatty liver in rats — rat in vivo animal modelView study →}. In skeletal-muscle cells osthole raised glucose uptake via AMPK activation and GLUT4 translocation ^{11Reference 11Lee WH et al. · 2011In vitroOsthole enhances glucose uptake through activation of AMP-activated protein kinase in skeletal muscle cells — in vitroView study →}, hinting at a broader anti-diabetic mechanism.

Gap: rat and cell models; doses and exposures are not human-validated, and osthole’s rapid metabolism complicates dosing for a chronic metabolic indication.

5. Anticancer

The broadest but thinnest signal. Isolated osthole induces apoptosis and cell-cycle arrest across cultured tumour lines: it enhanced radiation sensitivity and suppressed ATM/NF-κB signalling in cervical cancer cells ^{9Reference 9Che Y et al. · 2018In vitroOsthole enhances antitumor activity and irradiation sensitivity of cervical cancer cells by suppressing ATM/NF-κB signaling — in vitroView study →}, and inhibited proliferation while inducing apoptosis in ovarian cancer cells in vitro ^{10Reference 10Jiang G et al. · 2016In vitroAnti-tumor effects of osthole on ovarian cancer cells in vitro — in vitroView study →}. Reviews list similar activity in hepatocellular, renal and lung lines ^{1Reference 1Lin H et al. · 2024ReviewOsthole, a Coumarin from Cnidium monnieri: A Review on Its Pharmacology, Pharmacokinetics, Safety, and Innovative Drug Delivery Platforms — reviewView study →2Reference 2Zhang ZR et al. · 2015ReviewOsthole: A Review on Its Bioactivities, Pharmacological Properties, and Potential as Alternative Medicine — reviewView study →}.

Gap: almost entirely in-vitro at high micromolar concentrations that the poor oral bioavailability makes hard to reach systemically; in-vivo tumour work is sparse and there are no human oncology data.

Mechanisms

Target / pathway	Effect	Relevant to
Wnt/β-catenin + BMP-2/Smad	Activates → osteoblast differentiation, bone formation	Bone / osteoporosis
PDE4D	Inhibits (catalytic-site binding) → ↑cAMP/PKA, airway relaxation	Asthma
IL-33/ST2, NF-κB	Suppresses → ↓lung/tissue inflammation	Asthma, general anti-inflammatory
PPARα/γ	Activates → ↓hepatic lipid accumulation	Fatty liver / metabolic
AMPK → GLUT4	Activates → ↑glucose uptake	Metabolic / glucose
miR-9 / miR-107, BACE1, Nrf2	Modulates → neuronal differentiation, ↓amyloid, antioxidant	Neuroprotection
ATM/NF-κB, Bcl-2/Bax, caspase-3/9	Modulates → apoptosis, cell-cycle arrest	Anticancer

Pharmacokinetics

Bioavailability is the load-bearing caveat for the entire osthole literature. Osthole is highly lipophilic and poorly water-soluble, so its oral bioavailability as the pure compound is low and variable, and it undergoes rapid, extensive metabolism (over a dozen phase-I and phase-II metabolites identified in rat urine) with a short plasma half-life ^{1Reference 1Lin H et al. · 2024ReviewOsthole, a Coumarin from Cnidium monnieri: A Review on Its Pharmacology, Pharmacokinetics, Safety, and Innovative Drug Delivery Platforms — reviewView study →12Reference 12Sun C et al. · 2018AnimalPreparation and Pharmacokinetics Evaluation of Solid Self-Microemulsifying Drug Delivery System (S-SMEDDS) of Osthole — rat pharmacokinetic animal modelView study →}. This is why so much of the applied work leans on formulation tricks: a solid self-microemulsifying delivery system (S-SMEDDS) raised osthole exposure by roughly 200% over an aqueous suspension in rats ^{12Reference 12Sun C et al. · 2018AnimalPreparation and Pharmacokinetics Evaluation of Solid Self-Microemulsifying Drug Delivery System (S-SMEDDS) of Osthole — rat pharmacokinetic animal modelView study →}, borneol co-administration markedly increased AUC and Cmax by inhibiting metabolism and aiding absorption ^{14Reference 14Luo DD et al. · 2017AnimalDifferent effects of (+)-borneol and (−)-borneol on the pharmacokinetics of osthole in rats following oral administration — rat pharmacokinetic animal modelView study →}, and brain-targeting studies use intranasal nanoemulsions to bypass poor systemic delivery ^{14Reference 14Luo DD et al. · 2017AnimalDifferent effects of (+)-borneol and (−)-borneol on the pharmacokinetics of osthole in rats following oral administration — rat pharmacokinetic animal modelView study →}. Comparative rat studies also show tissue distribution and absorption differ between pure osthole and plant-extract matrices ^{13Reference 13Shi J et al. · 2013AnimalComparative study of pharmacokinetics and tissue distribution of osthole in rats after oral administration of pure osthole and Libanotis buchtormensis supercritical extract — rat pharmacokinetic animal modelView study →}. The practical upshot: potent in-vitro concentrations are not trivially reachable from an oral dose, which tempers every downstream claim.

Clinical trials

There are essentially no registered trials of isolated osthole; the human evidence is limited to traditional whole-seed Cnidium monnieri use, which is a plant-extract exposure and cannot be read as a molecule result. Everything in this page is preclinical.

Last checked: July 2026.

Toxicity & Safety

Osthole carries a low toxicity flag in the current literature: reviews describe it as generally well tolerated in animal studies with no signature acute organ toxicity at the doses used ^{1Reference 1Lin H et al. · 2024ReviewOsthole, a Coumarin from Cnidium monnieri: A Review on Its Pharmacology, Pharmacokinetics, Safety, and Innovative Drug Delivery Platforms — reviewView study →2Reference 2Zhang ZR et al. · 2015ReviewOsthole: A Review on Its Bioactivities, Pharmacological Properties, and Potential as Alternative Medicine — reviewView study →}, though a formal human safety database does not exist because the isolated molecule has not been trialled in people. Importantly, osthole is a simple prenylated coumarin, not a furanocoumarin — it lacks the fused furan ring that makes bergapten/psoralen-type furanocoumarins phototoxic and photocarcinogenic, so the classic furanocoumarin phototoxicity concern does not straightforwardly apply to osthole itself ^{1Reference 1Lin H et al. · 2024ReviewOsthole, a Coumarin from Cnidium monnieri: A Review on Its Pharmacology, Pharmacokinetics, Safety, and Innovative Drug Delivery Platforms — reviewView study →}. That said, osthole is often consumed as Cnidium seed extract, which also contains furanocoumarins (e.g. imperatorin, bergapten) that can be photosensitising — a whole-plant risk that is not an osthole risk. Osthole and its source seed carry an androgen-like/gonadotropin-like reputation in rodent sexual-behaviour studies (whole-extract data), so hormone-sensitive contexts warrant caution; interaction data with prescription drugs in humans are absent.

Dosage

There is no established human dose for isolated osthole. Preclinical work spans a wide range — commonly tens of milligrams per kilogram orally in rodents (e.g. the fatty-liver and neuroprotection studies) and high-micromolar concentrations in cell culture, figures inflated to compensate for poor absorption. Because oral bioavailability is low and metabolism rapid, extrapolating any of these to a human dose is speculative. These are doses studied in research and are not a personal recommendation.

References