# Estragole (4-allylanisole; found in Artemisia dracunculus, Ocimum tenuiflorum, Tagetes lucida)

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**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-04-02
**Evidence Score:** 1 / 10
**Category:** Compound
**Also Known As:** Estragole (1-allyl-4-methoxybenzene), Estragole (p-allylanisole; methyl chavicol), methyl chavicol, 1-methoxy-4-(2-propenyl)benzene, chavicol methyl ether, 4-allylanisole, CASRN 140-67-0, p-allylanisole, Estragole (Methyl Chavicol / p-Allylanisole)

## Overview

Estragole is a phenylpropanoid compound that exerts [antimicrobial](/ingredients/condition/immune-support), antioxidant, and [anti-inflammatory](/ingredients/condition/inflammation) activity by disrupting microbial cell membranes, scavenging [free radical](/ingredients/condition/antioxidant)s, and inhibiting cyclooxygenase (COX-1/COX-2) and lipoxygenase (5-LOX) enzymes. Preclinical in vitro data demonstrate minimum inhibitory concentrations ≤256 μg/mL against multidrug-resistant Gram-negative bacteria, COX-1 inhibition at IC₅₀ 59.2 ± 2.43 μg/mL, and up to 16-fold reduction in antibiotic MICs through synergistic combinations with meropenem and tobramycin, though no human clinical trials have been conducted.

## Health Benefits

- **Antimicrobial Activity**: Estragole disrupts bacterial cell membrane integrity, achieving 99.99% kill rates (MBC) against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus at concentrations of 0.0612–4% (w/v), with inhibition zones of 14.7–24.05 mm in disk diffusion assays.
- **Anti-inflammatory Effects**: The compound inhibits cyclooxygenase enzymes (COX-1 IC₅₀ 59.2 ± 2.43 μg/mL; COX-2 IC₅₀ 74.68 ± 1.34 μg/mL) and 5-lipoxygenase, suppressing the synthesis of pro-inflammatory prostaglandins and leukotrienes through dual-pathway blockade.
- **Antioxidant Action**: Estragole scavenges free radicals in DPPH assays with an IC₅₀ of 89.60 ± 8.73 μg/mL, inhibits xanthine oxidase at IC₅₀ 47.9 ± 2.04 μg/mL, and reduces lipid peroxidation at IC₅₀ 231.63 ± 5.21 μg/mL, collectively limiting oxidative cellular damage.
- **Antibiotic Synergy**: In fractional inhibitory concentration index (FICI) analyses, estragole combined with meropenem or tobramycin reduces the required antibiotic concentration by up to 16-fold against multidrug-resistant (MDR) and extensively drug-resistant (XDR) Gram-negative bacteria, suggesting utility as an antibiotic adjuvant in preclinical models.
- **[Immunomodulatory](/ingredients/condition/immune-support) Potential**: Through COX/LOX pathway inhibition and reduction of [pro-inflammatory cytokine](/ingredients/condition/inflammation)-driving eicosanoids, estragole may modulate immune cell activation and inflammatory cascades; this immunomodulatory activity has been characterized in vitro and ex vivo but not yet confirmed in human trials.
- **Selective Cytotoxicity Against Pathogens**: In brine shrimp (Artemia salina) lethality and hemolysis assays at 31.25–500 μg/mL, estragole demonstrated no significant cytotoxicity to host-model systems at antimicrobially relevant concentrations, indicating a favorable selectivity window distinct from its bactericidal doses.
- **Antioxidant Enzyme Inhibition**: Xanthine oxidase inhibition (IC₅₀ 47.9 μg/mL) positions estragole as a candidate for reducing [reactive oxygen species](/ingredients/condition/antioxidant) generation in hyperuricemia-associated oxidative stress models, though this application remains entirely preclinical.

## Mechanism of Action

At the membrane level, estragole intercalates into and disrupts bacterial phospholipid bilayers, increasing membrane permeability, dissipating the proton motive force, and ultimately causing cytoplasmic leakage and cell death at MBC concentrations. At the enzymatic level, estragole competitively inhibits both COX-1 and COX-2 isoforms (IC₅₀ 59.2 and 74.68 μg/mL, respectively) and 5-lipoxygenase, attenuating the conversion of arachidonic acid to pro-inflammatory prostaglandins and leukotrienes, which underpins its [anti-inflammatory](/ingredients/condition/inflammation) and putative [immunomodulatory](/ingredients/condition/immune-support) profile. As a free-radical scavenger, the electron-rich allyl and methoxy substituents on the phenylpropanoid scaffold donate hydrogen atoms to neutralize DPPH and peroxyl radicals, while xanthine oxidase inhibition reduces superoxide anion generation at IC₅₀ 47.9 μg/mL. At suprapharmacological concentrations (≥2000 μM, approximately ≥296 μg/mL), hepatic cytochrome P450 enzymes (primarily CYP1A2 and CYP2A6) and sulfotransferases bioactivate estragole to 1'-hydroxyestragole and its reactive sulfate ester or 2',3'-epoxide, which form DNA adducts and trigger apoptosis via genotoxic mechanisms, constituting the basis of its hepatocarcinogenic risk in rodent models.

## Clinical Summary

No human clinical trials investigating estragole as a therapeutic or nutritional supplement have been conducted or reported in the available peer-reviewed literature. All biological efficacy data originate from in vitro biochemical assays, microbiological susceptibility testing, and animal carcinogenicity studies, which precludes determination of effective human doses, pharmacokinetic parameters, or clinical outcomes. The absence of Phase I safety trials means that no maximum tolerated dose, no human bioavailability data, and no clinical effect sizes can be reported, and confidence in human applicability remains very low. Regulatory bodies including the FDA (GRAS for food-level exposure) and EFSA have evaluated estragole exclusively in the context of dietary exposure from herbs and spices, not as a concentrated supplement, further limiting its clinical development pathway.

## Nutritional Profile

Estragole is a pure organic phenylpropanoid compound (molecular formula C₁₀H₁₂O; MW 148.20 g/mol) and does not contribute macronutrients, vitamins, or dietary minerals when present at trace food-flavoring concentrations. Its chemical structure comprises a methoxyphenyl ring with a terminal allyl side chain, classifying it within the phenylpropanoid class alongside eugenol, anethole, and methylchavicol (a synonymous name); it is lipophilic (logP ~2.6), facilitating membrane partitioning and explaining its [antimicrobial](/ingredients/condition/immune-support) membrane-disruptive activity. In the context of essential oils where estragole predominates, co-occurring phytochemicals include β-ocimene (~14.56%), α-ocimene (~7.3%), D-limonene (~5.66%), and other monoterpenes that may contribute additive or synergistic bioactivities but are not nutritionally significant at dietary exposure levels. Bioavailability data in humans are absent; in rodent models, oral absorption is well-documented given its hepatic first-pass metabolic activation to carcinogenic intermediates, implying meaningful gastrointestinal absorption, but quantitative human pharmacokinetic parameters have not been established.

## Dosage & Preparation

- **Essential Oil (Steam Distillation)**: The primary commercial form; tarragon (Artemisia dracunculus) oil typically contains 57–85% estragole by GC-MS quantification; no established safe supplemental dose exists due to carcinogenic risk at elevated concentrations.
- **Ethanolic Plant Extract**: Used in research settings for [antioxidant](/ingredients/condition/antioxidant) and [anti-inflammatory](/ingredients/condition/inflammation) assays; estragole concentration varies significantly by solvent polarity and plant matrix; no standardized supplemental formulation available.
- **Food-Level Dietary Exposure**: Estragole is consumed incidentally via culinary use of tarragon, basil, anise, fennel, and star anise; this low-level exposure is covered under FDA GRAS status for flavoring use, not as a concentrated ingredient.
- **In Vitro Research Concentrations**: [Antimicrobial](/ingredients/condition/immune-support) activity observed at 0.0612–4% (w/v); antioxidant/enzyme inhibition at 31.25–1024 μg/mL; these are experimental reference concentrations, not dosing recommendations.
- **No Established Therapeutic Dose**: Due to the absence of human pharmacokinetic data, established bioavailability, and the carcinogenic risk from metabolic bioactivation, no standard supplemental dose can be recommended; isolated estragole supplementation is not advised.

## Safety & Drug Interactions

Estragole carries a documented hepatocarcinogenic risk through metabolic bioactivation: CYP450 enzymes convert it to 1'-hydroxyestragole, which is further sulfated to a reactive electrophile forming DNA adducts; this pathway is active in rodents at relatively low doses and is presumed to operate in humans, leading EFSA to classify it as a genotoxic carcinogen with no safe threshold, while the FDA GRAS designation applies narrowly to incidental food-flavoring exposure levels only. Cellular toxicity and apoptosis induction begin at concentrations ≥2000 μM (~296 μg/mL) in vitro, and no significant cytotoxicity was observed in brine shrimp or hemolysis assays at 31.25–500 μg/mL, suggesting a concentration-dependent toxicity profile, but human dose-response data are entirely absent. Drug interactions are primarily pharmacodynamic: synergistic combinations with meropenem and tobramycin (FICI-demonstrated, up to 16-fold MIC reduction) suggest potential for altered antibiotic dosing requirements; induction or inhibition of CYP1A2 and CYP2A6 by co-administered compounds could theoretically modulate estragole's bioactivation rate and carcinogenic risk. Estragole in supplemental or concentrated form is contraindicated in pregnancy, lactation, pediatric populations, and individuals with hepatic impairment or a history of liver disease; long-term or high-dose use is inadvisable for any population given the genotoxic risk, and no maximum safe supplemental dose has been established.

## Scientific Research

The entire body of evidence for estragole's bioactivities consists of in vitro cell-free assays, microbiological minimum inhibitory concentration studies, ex vivo cytotoxicity models (Artemia salina, erythrocyte hemolysis), and rodent carcinogenicity bioassays; no human clinical trials have been registered or published as of the available data. [Antimicrobial](/ingredients/condition/immune-support) studies employed standardized broth microdilution and disk diffusion methods with triplicate replicates against reference and MDR/XDR clinical isolates, reporting MIC values of 0.0612–4% and inhibition zones of 14.7–24.05 mm, providing reproducible but non-clinical evidence. [Antioxidant](/ingredients/condition/antioxidant) and enzyme inhibition parameters (DPPH IC₅₀ 89.60 μg/mL, XO IC₅₀ 47.9 μg/mL, COX-1 IC₅₀ 59.2 μg/mL) were derived from spectrophotometric biochemical assays without cellular or in vivo pharmacokinetic context, limiting translational interpretation. Carcinogenicity data derive from rodent feeding studies and metabolic activation assays demonstrating hepatotumorigenic potency approximately 35–275-fold weaker than diethylnitrosamine, forming the regulatory and toxicological basis for risk assessments by EFSA and related agencies; no sample sizes, confidence intervals, or effect sizes from human populations are available.

## Historical & Cultural Context

Estragole-rich plants have millennia-long records of medicinal and culinary use across diverse traditional systems: tarragon (Artemisia dracunculus) was documented in Ayurvedic and Unani medicine for digestive complaints, toothache, and as an appetitive stimulant, while holy basil (Ocimum tenuiflorum, tulsi) occupies a sacred position in Hindu tradition and Ayurveda as an [adaptogen](/ingredients/condition/stress) and [immunomodulat](/ingredients/condition/immune-support)or used in decoctions for respiratory and febrile illness. Anise (Pimpinella anisum) and fennel (Foeniculum vulgare), both estragole-containing, appear in ancient Egyptian, Greek, and Roman pharmacopeias as carminatives and galactagogues, with references in the Ebers Papyrus (~1550 BCE) and Dioscorides' De Materia Medica. Mexican tarragon (Tagetes lucida), known as 'pericón' or 'yauhtli,' was employed by Aztec and Mesoamerican healers as a ritual incense and medicinal tea for gastrointestinal and febrile conditions, reflecting the trans-cultural recognition of these plants' bioactive properties. The specific identification of estragole as the dominant active volatile in these preparations emerged only in the 20th century with advances in gas chromatography, separating the compound's pharmacological contributions from those of the complex phytochemical matrices in which it historically functioned.

## Synergistic Combinations

In [antimicrobial](/ingredients/condition/immune-support) applications, estragole demonstrates robust pharmacodynamic synergy with the beta-lactam antibiotic meropenem and the aminoglycoside tobramycin against MDR/XDR Gram-negative bacteria, as quantified by fractional inhibitory concentration index (FICI) analysis showing up to 16-fold reductions in required antibiotic concentrations; the proposed mechanism involves estragole-induced membrane permeabilization increasing intracellular antibiotic accumulation. Within its natural plant matrices, estragole co-occurs with monoterpenes such as β-ocimene, α-ocimene, and D-limonene, which may contribute additive membrane-disrupting and [antioxidant](/ingredients/condition/antioxidant) activities through complementary mechanisms, reflecting the entourage effect observed broadly in essential oil research. No human clinical evidence supports specific supplement stacking combinations involving isolated estragole, and given its carcinogenic metabolic profile, intentional combination with CYP1A2 or CYP2A6 inducers (e.g., rifampin, cruciferous vegetable extracts) would be theoretically hazardous by accelerating formation of genotoxic metabolites.

## Frequently Asked Questions

### Is estragole safe to take as a supplement?

Estragole is not recommended as an isolated supplement due to its genotoxic and hepatocarcinogenic potential: hepatic CYP450 enzymes convert it to 1'-hydroxyestragole, which forms DNA adducts associated with liver tumors in rodent models. The FDA's GRAS designation applies only to trace dietary exposure from culinary herbs like tarragon and basil, not to concentrated supplemental doses, and EFSA classifies it as a genotoxic carcinogen without a safe threshold for supplemental use.

### What plants contain the highest concentrations of estragole?

Tarragon (Artemisia dracunculus) essential oil contains the highest documented estragole concentrations, ranging from 57.23% in Egyptian cultivars to 60.3–84.9% in other regional variants and up to 69.34% in Turkish samples as quantified by GC-MS. Other significant sources include holy basil (Ocimum tenuiflorum), anise (Pimpinella anisum), fennel (Foeniculum vulgare), star anise (Illicium verum), and Mexican tarragon (Tagetes lucida), with concentrations varying by climate, harvest season, and extraction method.

### What are the anti-inflammatory mechanisms of estragole?

Estragole inhibits both cyclooxygenase isoforms—COX-1 at IC₅₀ 59.2 ± 2.43 μg/mL and COX-2 at IC₅₀ 74.68 ± 1.34 μg/mL—and 5-lipoxygenase (5-LOX), blocking the conversion of arachidonic acid into pro-inflammatory prostaglandins and leukotrienes via dual eicosanoid pathway suppression. These mechanisms have been demonstrated exclusively in cell-free biochemical and in vitro assays; no human clinical data exist to confirm equivalent anti-inflammatory activity at physiologically achievable concentrations in vivo.

### Does estragole have antibiotic properties?

Yes, preclinical data demonstrate that estragole exhibits bactericidal activity with MICs ≤256 μg/mL and 99.99% kill rates (MBC) against MDR and XDR Gram-negative bacteria, with inhibition zones of 14.7–24.05 mm against E. coli, B. subtilis, and S. aureus in disk diffusion assays. More notably, estragole acts synergistically with meropenem and tobramycin, reducing required antibiotic concentrations by up to 16-fold in FICI analyses, suggesting a potential adjuvant role in combating antibiotic-resistant infections, though this remains entirely at the preclinical stage.

### How does estragole differ from estrogen?

Estragole and estrogen are entirely unrelated compounds despite the phonetic similarity in their names: estragole (C₁₀H₁₂O) is a plant-derived phenylpropanoid volatile compound found in culinary herbs, characterized by a methoxyphenyl ring with an allyl side chain, with no known estrogenic receptor activity. Estrogens are a class of steroid hormones (e.g., estradiol, C₁₈H₂₄O₂) produced primarily in mammalian ovaries that regulate reproductive function via nuclear estrogen receptors (ERα, ERβ); the confusion arises solely from similar spelling and not from any chemical, functional, or mechanistic relationship.

### What does clinical research show about estragole's effectiveness against bacterial infections?

In vitro studies demonstrate that estragole achieves 99.99% kill rates (MBC) against common pathogens including Escherichia coli, Bacillus subtilis, and Staphylococcus aureus at concentrations of 0.0612–4% (w/v), with inhibition zones of 14.7–24.05 mm in disk diffusion assays. However, most evidence is from laboratory studies; human clinical trials specifically testing estragole's antimicrobial efficacy remain limited. The mechanism involves disruption of bacterial cell membrane integrity, though translation from in vitro to in vivo effectiveness requires further investigation.

### Can I get sufficient estragole from dietary sources like tarragon and basil instead of supplements?

Estragole is naturally present in culinary and medicinal plants including Artemisia dracunculus (tarragon), Ocimum tenuiflorum (holy basil), and Tagetes lucida (Mexican tarragon), making it possible to obtain the compound through diet. However, the concentration varies significantly by plant part, growth conditions, and processing methods, making it difficult to achieve consistent therapeutic doses through food alone. Supplemental forms may provide standardized dosing for those seeking specific health benefits, though whole plant extracts also contain complementary compounds that may enhance efficacy.

### Who should avoid estragole supplementation or use it with caution?

Estragole has demonstrated hepatotoxic and carcinogenic potential in animal models at high doses, raising concerns for individuals with existing liver disease or those taking hepatotoxic medications. Pregnant and breastfeeding women should exercise caution due to limited safety data in these populations. Additionally, individuals with estrogen-sensitive conditions may warrant medical consultation, as estragole's chemical structure resembles estrogen-like compounds, though it does not function as a direct estrogen receptor agonist.

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