Herniarin

Herniarin at a Glance

Herniarin, or 7-methoxycoumarin, is a simple plant coumarin — the O-methyl ether of umbelliferone (7-hydroxycoumarin). Where umbelliferone carries a free hydroxyl at the 7-position, herniarin carries a methoxy group; that single methylation is the whole story of the molecule, and the two compounds travel together through the plants that make them ^{6Reference 6Repčák M et al. · 2009Circadian rhythm of (Z)- and (E)-2-β-D-glucopyranosyloxy-4-methoxy cinnamic acids and herniarin in leaves of Matricaria chamomillaView study →}.

It recurs across the daisy family (Asteraceae) — most familiarly as one of the coumarins of chamomile, where it is a recognised aroma and quality marker — and appears in Mexican tarragon (Tagetes lucida), lavender, licorice and the rupturewort genus Herniaria that gives it its name ^{1,5,6Reference 1Monterrosas-Brisson N et al. · 2020Anti-inflammatory activity of coumarins isolated from Tagetes lucida CavView study →Reference 5Molnar M et al. · 2017Comparison of various techniques for the extraction of umbelliferone and herniarin in Matricaria chamomilla processing fractionsView study →Reference 6Repčák M et al. · 2009Circadian rhythm of (Z)- and (E)-2-β-D-glucopyranosyloxy-4-methoxy cinnamic acids and herniarin in leaves of Matricaria chamomillaView study →}. Its pharmacology is broad on paper — antispasmodic, vasorelaxant, anti-inflammatory, weakly cytotoxic and antimicrobial — but the honest posture is the usual one for a minor plant coumarin: the data are real yet almost entirely preclinical, isolated-molecule and whole-extract work in cells and rodents, with no controlled human trials ^{1,3,4Reference 1Monterrosas-Brisson N et al. · 2020Anti-inflammatory activity of coumarins isolated from Tagetes lucida CavView study →Reference 3Ventura-Martínez R et al. · 2020Study of antispasmodic and antidiarrheal activities of Tagetes lucida (Mexican tarragon) in experimental models and its mechanism of actionView study →Reference 4Estrada-Soto S et al. · 2021Antihypertensive and vasorelaxant mode of action of the ethanol-soluble extract from Tagetes lucida Cav. aerial parts and its main bioactive metabolitesView study →}.

One safety point is worth stating up front: herniarin is a simple coumarin, not a furanocoumarin. It lacks the fused furan ring that makes psoralen, bergapten and xanthotoxin phototoxic, so it does not carry their photosensitising / phototoxic risk.

Herniarin & Umbelliferone: The O-Methyl Pair

The defining fact about herniarin is its relationship to umbelliferone. The two are the same coumarin scaffold differing only at the 7-position: umbelliferone bears a free hydroxyl (7-OH), herniarin its methyl ether (7-OCH₃). Biosynthetically the plant builds herniarin by O-methylating the umbelliferone framework (via a glucosylated methoxycinnamic-acid precursor — see Its Role in Plants), and the two coumarins are repeatedly co-isolated from the same tissues ^{5,6Reference 5Molnar M et al. · 2017Comparison of various techniques for the extraction of umbelliferone and herniarin in Matricaria chamomilla processing fractionsView study →Reference 6Repčák M et al. · 2009Circadian rhythm of (Z)- and (E)-2-β-D-glucopyranosyloxy-4-methoxy cinnamic acids and herniarin in leaves of Matricaria chamomillaView study →}.

That structural kinship carries into the pharmacology. In the Tagetes lucida smooth-muscle work, umbelliferone and herniarin were tested side by side and both produced an antispasmodic effect on pre-contracted tissue — the pair, not either alone, accounting for much of the plant’s relaxant activity ^{3Reference 3Ventura-Martínez R et al. · 2020Study of antispasmodic and antidiarrheal activities of Tagetes lucida (Mexican tarragon) in experimental models and its mechanism of actionView study →}. Reading herniarin as “methylated umbelliferone” is therefore the most useful frame: it shares the parent’s broad, low-potency, antioxidant-adjacent coumarin behaviour, with the methyl ether shifting lipophilicity and metabolism rather than opening a distinct mechanism.

What It's Used For

Herniarin’s evidence is a spread of preclinical activities at modest potency, almost all generated as a constituent of Tagetes lucida or chamomile rather than as a stand-alone drug. Read the per-row basis below: every signal here is in-vitro or animal.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. Every row here is preclinical, so the scores are low by design; read the per-row basis.

01Antispasmodic & Vasorelaxant (smooth muscle)Shaky36%Two isolate-from-Tagetes studies: gut antispasmodic + vasorelaxant/antihypertensive ^{3,4Reference 3Ventura-Martínez R et al. · 2020Study of antispasmodic and antidiarrheal activities of Tagetes lucida (Mexican tarragon) in experimental models and its mechanism of actionView study →Reference 4Estrada-Soto S et al. · 2021Antihypertensive and vasorelaxant mode of action of the ethanol-soluble extract from Tagetes lucida Cav. aerial parts and its main bioactive metabolitesView study →}

02Anti-InflammatoryShaky30%Isolated herniarin, ~54% ear-oedema inhibition in mice ^{1Reference 1Monterrosas-Brisson N et al. · 2020Anti-inflammatory activity of coumarins isolated from Tagetes lucida CavView study →}

03Anticancer (Cytotoxic)Shaky24%In-vitro MCF-7, weak IC50 ~207.6 µM, apoptosis at high dose ^{2Reference 2Mousavi SH et al. · 2015Comparative analysis of the cytotoxic effect of 7-prenyloxycoumarin compounds and herniarin on MCF-7 cell lineView study →}

04AntimicrobialShaky22%In-vitro vs. the plant pathogen Ralstonia solanacearum ^{7Reference 7Han S et al. · 2021Preliminary studies on the antibacterial mechanism of a new plant-derived compound, 7-methoxycoumarin, against Ralstonia solanacearumView study →}

05AntioxidantShaky18%Whole chamomile extract, DPPH assay — one coumarin among many ^{5Reference 5Molnar M et al. · 2017Comparison of various techniques for the extraction of umbelliferone and herniarin in Matricaria chamomilla processing fractionsView study →}

Mechanisms

Nothing here is a validated human mechanism — each row is the readout of an isolated-tissue, cell or agricultural model.

Pharmacokinetics

Dedicated human pharmacokinetic data for herniarin are not established. As a small, lipophilic methoxycoumarin it would be expected to absorb readily and, like other 7-substituted coumarins, undergo hepatic oxidative metabolism — plausibly O-demethylation toward the umbelliferone (7-hydroxycoumarin) framework and subsequent conjugation — but this has not been characterised specifically for herniarin, and no oral bioavailability figure, active-metabolite profile or half-life is available. This absence is itself the key caveat: the in-vitro potencies above (hundreds of micromolar for cytotoxicity) cannot be mapped to any known achievable plasma level.

Clinical Trials

There are no clinical trials of isolated herniarin. Human exposure is dietary and indirect (chamomile tea, Mexican tarragon and other aromatic herbs), and what human-adjacent evidence exists belongs to the whole plants, not the molecule.

Last checked: July 2026.

Isolate vs. Plant Studies

Herniarin’s evidence is an unusual mix of isolate and plant. The pharmacology papers mostly test herniarin isolated from a plant — purified from Tagetes lucida and then run in isolated-tissue or rodent models ^{1,3,4Reference 1Monterrosas-Brisson N et al. · 2020Anti-inflammatory activity of coumarins isolated from Tagetes lucida CavView study →Reference 3Ventura-Martínez R et al. · 2020Study of antispasmodic and antidiarrheal activities of Tagetes lucida (Mexican tarragon) in experimental models and its mechanism of actionView study →Reference 4Estrada-Soto S et al. · 2021Antihypertensive and vasorelaxant mode of action of the ethanol-soluble extract from Tagetes lucida Cav. aerial parts and its main bioactive metabolitesView study →} — which is a strength for attributing the activity to the molecule, but every one of those readouts is still preclinical. The antispasmodic and vasorelaxant work explicitly frames herniarin as one of two or three coumarins jointly responsible for the parent extract’s effect, so its individual contribution to the whole-plant action is partial ^{3,4Reference 3Ventura-Martínez R et al. · 2020Study of antispasmodic and antidiarrheal activities of Tagetes lucida (Mexican tarragon) in experimental models and its mechanism of actionView study →Reference 4Estrada-Soto S et al. · 2021Antihypertensive and vasorelaxant mode of action of the ethanol-soluble extract from Tagetes lucida Cav. aerial parts and its main bioactive metabolitesView study →}. The antioxidant signal is the opposite case — a whole chamomile extract in which herniarin is merely one phenolic ^{5Reference 5Molnar M et al. · 2017Comparison of various techniques for the extraction of umbelliferone and herniarin in Matricaria chamomilla processing fractionsView study →}. No study bridges any of this to a human outcome.

Its Role in Plants

In plants, herniarin behaves as a phytoanticipin — a pre-formed chemical defence. Chamomile does not store the free coumarin so much as its glucosylated precursors, the (Z)- and (E)-2-β-D-glucopyranosyloxy-4-methoxycinnamic acids (GMCA). When tissue is disrupted, a specific β-glucosidase hydrolyses the (Z)-glucoside and the aglycone spontaneously lactonises to herniarin ^{6Reference 6Repčák M et al. · 2009Circadian rhythm of (Z)- and (E)-2-β-D-glucopyranosyloxy-4-methoxy cinnamic acids and herniarin in leaves of Matricaria chamomillaView study →}. Because of this, much of the herniarin measured in chamomile products is effectively liberated during harvesting and processing rather than present intact in the living leaf — which is why measured content is so processing-dependent.

The precursors and the coumarin show a circadian rhythm (GMCA peaking before daybreak, herniarin accumulating through the morning), and both the precursor pool and herniarin rise on herbivore attack and stress elicitation — evidence the pathway is part of the plant’s inducible defence system ^{6Reference 6Repčák M et al. · 2009Circadian rhythm of (Z)- and (E)-2-β-D-glucopyranosyloxy-4-methoxy cinnamic acids and herniarin in leaves of Matricaria chamomillaView study →}. These are plant-biology functions and should not be read as human pharmacology.

Prevalence in Nature

Herniarin is one of the more widespread simple coumarins, recurring across several plant families — reported in the Asteraceae (chamomile, Tagetes, Artemisia), Lamiaceae (lavender), Caryophyllaceae (Herniaria, its namesake), and among the Rutaceae, Fabaceae and others ^{1,5Reference 1Monterrosas-Brisson N et al. · 2020Anti-inflammatory activity of coumarins isolated from Tagetes lucida CavView study →Reference 5Molnar M et al. · 2017Comparison of various techniques for the extraction of umbelliferone and herniarin in Matricaria chamomilla processing fractionsView study →}. It is usually a minor constituent, and its concentration in any given sample is heavily influenced by post-harvest processing because so much is generated from GMCA precursors on tissue disruption ^{6Reference 6Repčák M et al. · 2009Circadian rhythm of (Z)- and (E)-2-β-D-glucopyranosyloxy-4-methoxy cinnamic acids and herniarin in leaves of Matricaria chamomillaView study →}.

The best-quantified source is chamomile: comparing extraction techniques, a macerated chamomile processing-waste fraction yielded about 82.79 mg herniarin per 100 g (with ~11.8 mg/100 g umbelliferone) — notably, the waste stream, not the flower head, was the richest fraction, underscoring how much the number depends on plant part and preparation ^{5Reference 5Molnar M et al. · 2017Comparison of various techniques for the extraction of umbelliferone and herniarin in Matricaria chamomilla processing fractionsView study →}. In Mexican tarragon (Tagetes lucida) herniarin is a recurrent aerial-part coumarin isolated alongside scopoletin, umbelliferone and scoparone ^{1,3Reference 1Monterrosas-Brisson N et al. · 2020Anti-inflammatory activity of coumarins isolated from Tagetes lucida CavView study →Reference 3Ventura-Martínez R et al. · 2020Study of antispasmodic and antidiarrheal activities of Tagetes lucida (Mexican tarragon) in experimental models and its mechanism of actionView study →}.

Discovery & Synthesis

First isolation. Herniarin takes its name from the rupturewort genus Herniaria (traditionally used for hernias and urinary complaints), from which the coumarin was characterised; it is also long documented as ayapanin, the name under which it was described from Ayapana/Eupatorium herbs. A precise first-isolation date is not well documented in the accessible literature.

Synthesis. As the 7-methoxy ether of umbelliferone, herniarin is readily obtained by O-methylation of umbelliferone (e.g. with dimethyl sulfate or methyl iodide), and umbelliferone itself is a standard Pechmann-condensation product from resorcinol — so herniarin is trivially accessible synthetically and is sold as a research chemical. Its first dedicated total synthesis is not separately notable given this one-step relationship to a classic coumarin.

Patents: not yet researched.

Toxicity & Safety

Herniarin carries a low flag. It occurs at low levels in commonly consumed herbs (chamomile tea, culinary Mexican tarragon), and no specific human toxicity syndrome is associated with it at those exposures. The most important safety point is what it is not: a furanocoumarin.

Safety at a Glance

✅ Low / no toxicity

• Not a furanocoumarin, not phototoxic. Herniarin is a simple methoxycoumarin lacking the fused furan ring — it does not carry the photosensitising / phototoxic and skin-reaction risk of psoralen, bergapten or xanthotoxin.
• Low-level dietary exposure is long-standing. Present as a minor coumarin in chamomile and other aromatic herbs consumed traditionally as teas and seasonings.
• Coumarin-class context. It is a member of the coumarin family; the hepatotoxicity concern attached to high-dose simple coumarin (the parent 2H-chromen-2-one) has not been specifically characterised for herniarin, and dedicated high-dose / repeat-dose human safety data are lacking.
• No interaction or reproductive dataset. Drug-interaction (CYP), genotoxicity and reproductive-toxicity profiles for isolated herniarin are not established; absence of data is not evidence of safety, and intake decisions belong to the herb/product page.

Dosage

There is no established human dose for isolated herniarin. The concentrations in the research above are preclinical: an anti-oedema effect in a topical mouse model ^{1Reference 1Monterrosas-Brisson N et al. · 2020Anti-inflammatory activity of coumarins isolated from Tagetes lucida CavView study →}, vasorelaxant and antispasmodic activity in isolated tissue ^{3,4Reference 3Ventura-Martínez R et al. · 2020Study of antispasmodic and antidiarrheal activities of Tagetes lucida (Mexican tarragon) in experimental models and its mechanism of actionView study →Reference 4Estrada-Soto S et al. · 2021Antihypertensive and vasorelaxant mode of action of the ethanol-soluble extract from Tagetes lucida Cav. aerial parts and its main bioactive metabolitesView study →}, and cytotoxicity at an IC50 of roughly 207.6 µM on a cancer cell line ^{2Reference 2Mousavi SH et al. · 2015Comparative analysis of the cytotoxic effect of 7-prenyloxycoumarin compounds and herniarin on MCF-7 cell lineView study →} — a concentration far above anything reached from drinking chamomile tea. Human exposure is dietary and indirect, as a minor coumarin in chamomile, Mexican tarragon and related aromatic herbs. These are figures from research, not a personal recommendation.

References

1. Monterrosas-Brisson N, et al. (2020). Anti-inflammatory activity of coumarins isolated from Tagetes lucida Cav. Natural Product Research. https://pubmed.ncbi.nlm.nih.gov/30618303/
2. Mousavi SH, et al. (2015). Comparative analysis of the cytotoxic effect of 7-prenyloxycoumarin compounds and herniarin on MCF-7 cell line. Avicenna Journal of Phytomedicine. https://pubmed.ncbi.nlm.nih.gov/26693409/
3. Ventura-Martínez R, et al. (2020). Study of antispasmodic and antidiarrheal activities of Tagetes lucida (Mexican tarragon) in experimental models and its mechanism of action. Evidence-Based Complementary and Alternative Medicine. https://pubmed.ncbi.nlm.nih.gov/33193797/
4. Estrada-Soto S, et al. (2021). Antihypertensive and vasorelaxant mode of action of the ethanol-soluble extract from Tagetes lucida Cav. aerial parts and its main bioactive metabolites. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/32961278/
5. Molnar M, et al. (2017). Comparison of various techniques for the extraction of umbelliferone and herniarin in Matricaria chamomilla processing fractions. Chemistry Central Journal. https://pubmed.ncbi.nlm.nih.gov/29086851/
6. Repčák M, et al. (2009). Circadian rhythm of (Z)- and (E)-2-β-D-glucopyranosyloxy-4-methoxy cinnamic acids and herniarin in leaves of Matricaria chamomilla. Plant Cell Reports. https://pubmed.ncbi.nlm.nih.gov/19430793/
7. Han S, et al. (2021). Preliminary studies on the antibacterial mechanism of a new plant-derived compound, 7-methoxycoumarin, against Ralstonia solanacearum. Frontiers in Microbiology. https://pubmed.ncbi.nlm.nih.gov/34421853/

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