Anise (Pimpinella anisum L.)
1. Identity: Botanical Classification, Chemistry, and Common Forms
Botanical and Chemical Names
Anise (Pimpinella anisum), also called aniseed, is a flowering plant in the family Apiaceae, native to the eastern Mediterranean region and Southwest Asia. The name "anise" is derived via Old French from the Latin words anīsum or anēthum, from the Greek ánēthon, referring to dill. The genus name Pimpinella derives from the Latin dipinella, referring to the pinnately divided form of the leaves.
Anise should not be confused with star anise (Illicium verum), which has an almost identical taste but comes from a different botanical family and is considered to be stronger in action. Star anise belongs to the Schisandraceae family, whereas anise (Pimpinella anisum) is of the Apiaceae family, related to dill, cumin, and fennel.
Botanical Description
Pimpinella anisum L. is an aromatic, annual grassy herb with 30–50 cm height, bearing white flowers and small green to yellow seeds, with secondary feather-like leaflets of bright green, twice pinnate. The plant bears white to yellowish-white flowers in compound umbels. When ripe, the fruits are about 3 mm long and oval-shaped with grayish-green coloring. While the entire plant is fragrant and tastes strongly of anise, it is the aniseed fruit that has been highly valued since antiquity. Seed maturation usually occurs one month after pollination, when the oil content in the dried fruit is about 2.5%.
Geographic Origin and Cultivation
Anise (Pimpinella anisum) has a long history of usage in traditional and alternative medicine, as well as in the pharmaceutical sector. The species is native to Southwest Asia, the Middle East, and the Mediterranean region. Anise has a history of use as a spice and fragrance, and has been cultivated in Egypt for at least 4,000 years. Commercial cultivation today occurs across Southern Europe, North Africa, the Middle East, and parts of Asia.
Common Forms and Preparations
As a herbal substance, aniseed is administered in liquid or, after crushing, in solid dosage forms. Common preparations include:
- Whole or crushed dried fruits (seeds): The primary medicinal part, used directly or as an infusion (herbal tea). The single dose specified in the ESCOP monograph consists of 1–5 g of crushed fruits in 150 ml of water as a herbal tea.
- Essential oil (Anisi aetheroleum): Anisi aetheroleum is the essential oil obtained by steam distillation from P. anisum (family: Apiaceae). Oil of Anise distilled in Europe from the fruits of Pimpinella anisum is colourless, or very pale yellow, with taste and odour like the fruit.
- Standardized extracts and capsules: Used in clinical research; capsule preparations containing standardized powdered extract have been employed in human trials.
- Tinctures and fluid extracts: Alcoholic preparations used in traditional and phytopharmaceutical practice.
- Food use: Anise is used widely as a flavoring in all food categories including alcohols, liqueurs, dairy products, gelatins, puddings, meats, and candies.
2. Traditional and Historical Use
Ancient Egypt and the Near East
Anise (Pimpinella anisum) is native to the Mediterranean region, perhaps Egypt. The ancient Egyptian term inst is equated with anise and is mentioned in the Papyrus Ebers (c. 1550 BCE) as a medicine used to treat abdominal and dental diseases. Anise has been cultivated in Egypt for at least 4,000 years. Recordings of its diuretic use and treatment of digestive problems and toothache are seen in medical texts from this era.
Ancient Greece and Rome
Many of the well-known Greek and Roman authors, including Dioscorides, Theophrastus, Pliny, and Palladus, spoke of the cultivation and uses of anise. Hippocrates, the father of Greek medicine, recommended its use for digestive issues and respiratory problems. Similarly, Pliny the Elder, a renowned Roman writer, suggested anise seed as a remedy for bloating. Pliny, the Roman generalist, reported two esteemed varieties of anise, one from Crete and one from Egypt. Pliny also reported that anise mixed with wine was used by the Egyptians to treat bites from poisonous snakes and, when mixed with cucumber seeds, linseed, and white wine, to dispel childbirth-related vertigo.
The ancient Romans often served spiced cakes flavored with aniseed, called mustaceoe, at the end of feasts as a digestive. Anise is a native of Egypt, Greece, Crete and Asia Minor, was cultivated by the ancient Egyptians, was well known to the Greeks, being mentioned by Dioscorides and Pliny, and was cultivated in Tuscany in Roman times. In the Middle Ages, its cultivation spread to Central Europe.
Islamic and Persian (Iranian) Traditional Medicine
In ancient times, anise seed was used to aid childbirth and stimulate milk production, and ancient medical books described its anti-asthma and anticonvulsant effects. In ancient Islamic medicine, the seeds were considered effective for the relief of pain, gastrointestinal distress, paralysis, for improving kidney function, and for treating facial disorders. Iranian folk medicine recommended the seeds for treating epilepsy, melancholy, nightmares, and seizures.
In the Traditional Medicine of Iran, anise seeds are used as a diuretic, galactagogue, emmenagogue, diaphoretic, an analgesic for migraines, and to reduce hot flashes related to menopause.
North Africa and the Levant
In Egypt and Lebanon, this plant was used to treat digestive and respiratory ailments. In Morocco, the seeds of anise were used as an aphrodisiac, as well as a remedy for menstrual pains, diabetes, and diverse respiratory problems. In Turkish medicine, anise was considered as an agent to fight infections, inflammation, and liver disorders.
Indian Traditional Medicine
In the traditional system of Indian medicine, aniseed is used as antiseptic, stomachic, carminative, stimulant and to prevent flatulence and colic. In traditional medicine, the drug is also reputed to alleviate pain associated with the female cycle and to be a galactagogue and aphrodisiac.
Medieval and Early Modern Europe
Charlemagne, in the ninth century, commanded that anise be grown on the imperial farms. Anise has been used medicinally from antiquity into the Middle Ages to treat a wide range of disorders, among them gallbladder, kidney, and liver complaints, hiccough, and "falling sickness" (epilepsy) in children. As the Roman Empire expanded and trade routes grew, anise was incorporated into various culinary applications, baked goods, traditional medicine, and numerous alcoholic beverages characterized by their distinctive anise flavor, such as absinthe, sambuca, anisette, Pernod, and pastis.
3. Key Constituents and Active Compounds
Essential Oil Composition
Aniseed contains 1.5–6.0 mass % of a volatile oil consisting primarily of trans-anethole, and also as much as 8–11 mass % of lipids rich in fatty acids such as palmitic and oleic acids, as well as approximately 4 mass % of carbohydrates, and 18 mass % of protein.
Regardless of the method of isolation, the main component of the oil is anethole (80–90%), with minor components including 4-anisaldehyde, estragole, and pseudoisoeugenyl-2-methylbutyrates. Oil content is 2–6% by weight of raw seed material, with 74–94% of that fraction being trans-anethole, and the remaining fraction consisting of estragole (methylchavicol), anisaldehyde, and γ-himachalene.
In a study examining composition of essential oil of Pimpinella anisum L. fruits obtained from different geographical areas of Europe, in addition to the major components (trans-anethole at 76.9–93.7% and γ-himachalene at 0.4–8.2%), some other compounds such as trans-pseudoisoeugenyl 2-methylbutyrate, p-anisaldehyde, and methylchavicol were also identified.
Trans-Anethole: The Principal Bioactive
Anethole is the most important chemical constituent of anise and is the most used in food, medicine, as well as in the industries of pharmaceuticals, perfumery, flavouring, and pesticides. Anethole is a naturally occurring aromatic phenylpropene compound commonly present in the essential oils derived from botanically diverse plants, including anise, star anise, fennel, and basil. Anethole is responsible for anise's characteristic odor and flavor.
Other Phytochemical Classes
Although the major component of anise oil is trans-anethole (75–90%), other constituents include coumarins (umbelliferone, umbelliprenine, bergapten, and scopoletin), lipids (fatty acids, beta-amyrin, stigmasterol, and its salts), and flavonoids (flavonol, flavone, glycosides, rutin, isoorientin). Other studies have demonstrated the presence of eugenol, trans-anethole, methylchavicol, anisaldehyde, estragole, coumarins, scopoletin, umbelliferone, estrols, terpene hydrocarbons, polyenes, and polyacetylenes as major compounds of the essential oil.
Current studies have revealed that wild and cultivated P. anisum are rich in bioactive compounds such as phenols, tannins, carotenoids, and fatty acids.
Estragole: A Minor Constituent of Regulatory Concern
Estragole is a minor constituent of anise oil. Its presence has generated regulatory attention due to preclinical carcinogenicity signals (see Safety section below).
4. Established Mechanisms of Action
Antispasmodic / Smooth Muscle Relaxation
Mechanistic evaluation has revealed that anethole blocks voltage-dependent calcium channels, reducing Ca²⁺ influx and thereby exerting antispasmodic effects. IC50 values were 89.9 μg/mL for KCl-induced and 160.5 μg/mL for ACh-induced contractions, with maximal pharmacodynamic efficacy. This mechanism accounts for anise's traditional reputation as a carminative and antispasmodic agent in the gastrointestinal tract.
Antimicrobial Activity
Anethole has potent antimicrobial properties against bacteria, yeasts, and fungi. Reported antibacterial properties include both bacteriostatic and bactericidal action against Salmonella enterica. Studies have shown that anethole is effective against bacteria such as Staphylococcus aureus and fungi such as Candida albicans. Aniseed oil exhibited in vitro strong inhibitory activities against the growth of a wide spectrum of bacteria and fungi known to be pathogenic for humans. An acetone extract of aniseed inhibited the growth of a range of bacteria including Escherichia coli and Staphylococcus aureus, and also exhibited antifungal activity against Candida albicans and other species.
Estrogenic / Phytoestrogenic Effects
The plant oil demonstrates pharmacological properties including estrogenic effects. Estrogenic activity described for trans-anethole is not confirmed for aniseed alcoholic extracts on the basis of epidemiological data related to the common use of aniseed alcoholic beverages. The exact estrogenic mechanism remains a subject of ongoing investigation; anethole and its polymers (dianethole, photoanethole) have been proposed as the relevant compounds.
Anti-inflammatory and Antioxidant Mechanisms
Previous studies have reported anticancer activity for anethole; it affects pathways such as NF-κB and caspase cascades affecting cell survival and apoptosis. The compound's mechanism of action involves acting as an antioxidant and an anti-stimulant, serving as a mitochondrial protector.
Neurological Mechanisms
An evaluation of anethole by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) found its notable pharmacologic properties to include reduction in motor activity, lowering of body temperature, and hypnotic, analgesic, and anticonvulsant effects. Anethole exhibits a protective effect against cortical neuronal injury caused by oxygen-glucose deprivation/reoxygenation, possibly by inhibiting the toxic activities of excitatory neurotransmitters, reducing the production of reactive oxygen species (ROS), and mitigating dysfunctional mitochondria.
Metabolic Mechanisms
It has been demonstrated that anethole has the ability to improve metabolic parameters such as insulin sensitivity and reduce lipid metabolism in preclinical studies.
5. Scientific Evidence by Area of Use
5.1 Gastrointestinal System: Functional Dyspepsia
The strongest body of human clinical evidence for anise concerns gastrointestinal complaints, particularly functional dyspepsia (FD).
A double-blind randomized clinical trial aimed to evaluate the effects of Pimpinella anisum on relieving symptoms of postprandial distress syndrome (PDS). A total of 107 patients attending a gastroenterology clinic, aged 18–65 years, diagnosed with PDS according to Rome III criteria, were enrolled. They were randomized to receive either anise or placebo blindly for 4 weeks. The anise group included 47 patients and received anise powders, 3 g after each meal (3 times/day). The control group of 60 patients received placebo powders (corn starch), 3 g after each meal (3 times/day). The severity of FD symptoms was assessed by the FD severity scale, with assessments done at baseline and at the end of weeks 2, 4, and 12.
A parallel trial examined quality of life (QOL): the aim was to assess the effects of anise on QOL of patients with FD in a double-blind randomized clinical trial. Of 180 patients attending the gastroenterology clinic, 107 with the diagnosis of postprandial distress syndrome according to Rome III criteria were enrolled. They were randomized into anise and placebo groups. The anise group (47 patients) received anise powders, 3 g after each meal (3 times/day) for 4 weeks. The control group (60 patients) received placebo powders (cornstarch), 3 g after each meal (3 times/day) for 4 weeks. QOL was assessed by the short-form (SF)-36 questionnaire. The study revealed the effectiveness of anise in improvement of quality of life in patients with FD.
Evidence strength: These represent controlled human trials with placebo comparators. Limitations include a modest patient population, short duration of intervention, and single-center setting. Overall, evidence is preliminary but directionally positive for functional dyspepsia.
5.2 Gastrointestinal System: Carminative and Antispasmodic Effects
Aniseeds contain 1.5–5% essential oil and are used as flavoring, digestive, carminative, and relief of gastrointestinal spasms. The findings from pharmacological studies revealed that aniseeds can cause gastric protection, muscle relaxation, and affect the digestive system. These effects are primarily supported by preclinical (animal and in vitro) evidence and align with the calcium-channel–blocking antispasmodic mechanism identified for anethole. Robust large-scale human trials specifically for carminative effects are lacking.
5.3 Women's Health: Menopausal Hot Flashes
In a double-blind clinical trial, the effect of anise extract on menopausal hot flashes in 72 postmenopausal women was examined. Consumption of 3 capsules of anise extract (each capsule containing 100 mg of extract) for 4 weeks led to a significant reduction in hot flash frequency and intensity in postmenopausal women.
A separate larger study corroborates these findings: a double-blind clinical trial was conducted to determine the effects of Pimpinella anisum on hot flashes in 72 postmenopausal women referring to rural and urban health centers of Qazvin Province. Each woman in the experimental group took a capsule containing 330 mg Pimpinella anisum 3 times a day, while in the control group women took 3 capsules each containing 330 mg potato starch over 4 weeks, followed by 4 weeks of follow-up. Before taking the capsules, they were assessed for 2 weeks about the frequency and severity of hot flashes.
Findings from subsequent trials similarly concluded that Pimpinella anisum is an effective herbal medicine in reducing the severity and frequency of hot flashes.
Evidence strength: Multiple small double-blind RCTs exist with consistent positive findings. All are relatively small (72 patients or fewer), conducted in Iran, and of short duration. Independent replication in diverse populations is lacking. Evidence is preliminary but consistently positive within this limited body of trials.
5.4 Women's Health: Dysmenorrhea
Aniseed has been reported to have beneficial effects on dysmenorrhea. In a study by Karami et al., 180 female students (aged 17–28) with primary dysmenorrhea had their response to a herbal capsule containing dried extracts of celery, saffron, and anise compared to a capsule containing mefenamic acid. As anise was used in combination with other herbs in this study, its independent contribution to efficacy cannot be determined from the available data.
Evidence strength: Very limited, primarily from combination herbal trials. The independent efficacy of anise for dysmenorrhea remains unestablished in rigorous human trials.
5.5 Antimicrobial Activity
A study identified 13 compounds in anise essential oil, of which trans-anethole was in the highest proportion (72.49%), followed by limonene (10.01%), anisole (5%), and α-pinene (3.26%). Statistical analysis indicated significant antimicrobial activity (p < 0.001) of anise essential oil. Anise essential oil demonstrated important antimicrobial activity against both Gram-positive and Gram-negative pathogens, with high inhibition percentages for P. aeruginosa and S. aureus, and excellent antifungal activity against C. albicans.
Evidence strength: This evidence is primarily in vitro (laboratory-based), with some animal data. No adequately powered human clinical trials have demonstrated clinical antimicrobial benefit from anise preparations. Results cannot be directly translated to clinical treatment without further study.
5.6 Metabolic Effects: Diabetes and Lipid Profile
In diabetic patients, aniseeds have shown hypoglycemic and hypolipidemic effects and reduce lipid peroxidation. In diabetic patients, aniseeds showed hypoglycemic and hypolipidemic effects and reduced lipid peroxidation. Aniseeds and coriander seeds were evaluated in type 2 diabetes patients for their antidiabetic, hypolipidemic, and antioxidant properties.
Limited and preliminary clinical research has examined the efficacy of aniseed toward diabetes, dysmenorrhea, and menopausal hot flashes. Antioxidant, anti-inflammatory, and antimicrobial properties have also been identified.
Evidence strength: The antidiabetic and hypolipidemic effects are supported primarily by animal studies and a small number of preliminary human studies. The clinical evidence base is insufficient to draw firm conclusions.
5.7 Respiratory System: Expectorant and Bronchodilatory Effects
The plant is used for the treatment of dyspepsia, inflammation of the respiratory tract, and chronic bronchitis. Use of aniseed products (tincture) as an expectorant in cough and cold is not supported by scientific data; however, it is described in traditional medicine. The plant oil demonstrates pharmacological properties including bronchodilatory and expectorant effects.
Evidence strength: Expectorant and bronchodilatory uses rest almost entirely on traditional use and preclinical/in vitro data. There are no adequately controlled human trials demonstrating clinical efficacy for respiratory conditions.
5.8 Galactagogue (Lactation Support)
Consumption of aniseed in lactating women increases milk and also relieves their infants from gastrointestinal problems. The effectiveness of herbal teas containing lemon balm, nettle, fennel, caraway, or aniseed extracts was analyzed; their use helped increase lactation without adverse side effects in the studied populations.
Evidence strength: Studies in this area are few, small, and often involve multi-ingredient herbal teas rather than anise alone. The independent galactagogue effect of anise in humans has not been definitively established.
5.9 Neurological and Analgesic Effects
Various studies have reported properties including anticonvulsant and analgesic activities for aniseeds. Various scientific reports have highlighted the role of anethole in safeguarding the nervous system. Previous studies have identified its potential in the treatment of ischemic stroke. Anethole exhibits a protective effect against cortical neuronal injury caused by oxygen-glucose deprivation/reoxygenation, possibly by inhibiting the toxic activities of excitatory neurotransmitters, reducing the production of reactive oxygen species (ROS), and mitigating dysfunctional mitochondria.
Evidence strength: Neurological and analgesic effects are derived primarily from animal models and in vitro experiments. There is no adequate body of human clinical evidence for these uses.
5.10 Overall Evidence Assessment
Due to the broad spectrum of pharmacological effects identified in preclinical studies, and very few clinical studies of Pimpinella anisum, more clinical trials are recommended to evaluate the beneficial effects of this plant in human models and for synthesis of new drugs from the active ingredients of this plant. The totality of scientific evidence, while extensive in preclinical settings, remains at an early or preliminary stage for most clinical applications.
6. Body Systems and Health Areas
Based on traditional use, pharmacological research, and the limited clinical literature, anise is associated with the following body systems and health areas:
- Gastrointestinal system: Carminative, antispasmodic, gastric-protective, anti-dyspeptic, laxative (folk use for constipation), and anti-flatulent effects.
- Respiratory system: Expectorant, bronchodilatory, and mucolytic activities — supported by traditional use and preclinical evidence.
- Female reproductive / endocrine system: Estrogenic effects, galactagogue, emmenagogue, relief of dysmenorrhea, and mitigation of menopausal hot flashes.
- Metabolic system: Preliminary evidence for hypoglycemic and hypolipidemic effects in diabetic patients.
- Immune / antimicrobial: Broad-spectrum antimicrobial activity against bacteria and fungi demonstrated in vitro.
- Nervous system: Anticonvulsant, analgesic, anxiolytic, and neuroprotective effects identified in preclinical models.
- Antioxidant / anti-inflammatory: Scavenging of reactive oxygen species and modulation of NF-κB-mediated inflammatory pathways, primarily at the preclinical level.
The antimicrobial, antifungal, antiviral, hepatoprotective, anti-inflammatory, anticonvulsant, antispasmodic, estrogenic, expectorant, and insecticidal effects are among the pharmacological effects reported, as are clinical effects including relief of nausea, constipation, bronchodilation, menopause symptoms, diabetes management, and sedative action.
7. Dosage Forms and Reported Dosages
Dosages presented here are those reported in authoritative monographs and cited clinical research, not recommendations.
- Herbal tea (infusion) — crushed or ground aniseed:
The single dose specified in the ESCOP monograph consists of 1–5 g of crushed fruits in 150 ml of water as a herbal tea. The revised ESCOP monograph confirms an adult average daily dose of 3 g. For the powder, 0.2 to 2 g per day are recommended.
- Essential oil (Anisi aetheroleum):
The average daily dose of Anisi aetheroleum is 0.3 g according to one clinical pharmacology source.
- Standardized extract capsules — functional dyspepsia trials:
Patients in clinical trials received anise powders, 3 g after each meal (3 times/day), while controls received placebo powders (corn starch), 3 g after each meal (3 times/day), over 4 weeks.
- Extract capsules — menopausal hot flash trials:
Each woman in the experimental group took a capsule containing 330 mg Pimpinella anisum extract 3 times a day (total 990 mg/day) over 4 weeks. An earlier trial used 3 capsules of anise extract, each containing 100 mg of extract (total 300 mg/day), for 4 weeks.
- Duration guidance from EMA:
Because of the lack of available safety data on long-term use of aniseed preparations, and due to the presence of compounds such as trans-anethole and estragole, a limit of two weeks is consistent with a self-medication indication for traditional herbal medicinal products.
8. Safety Considerations and Known Interactions
8.1 General Safety Profile
A subsequent evaluation by JECFA found some reason for concern regarding carcinogenicity, but there is currently insufficient data to support this. The JECFA summary is that anethole has "no safety concern at current levels of intake when used as a flavoring agent." In large quantities, anethole is slightly toxic and may act as an irritant.
8.2 Allergic Reactions
According to the Complete German Commission E Monographs, adverse effects of anise include occasional allergic reactions of the skin, respiratory tract, and GI tract. When applied to human skin at a 2% concentration in a petrolatum base, anise oil produced no dermatological reactions. Anise may be photosensitizing and allergenic, causing reactions in the respiratory tract, gastrointestinal tract, and skin. It should not be used by individuals who have allergies to anise and/or anethole.
8.3 Estragole: Potential Carcinogenicity Concern
Because of the lack of available safety data on long-term use of aniseed preparations, and due to the presence of compounds such as trans-anethole and estragole, a limit of two weeks is consistent with a self-medication indication for traditional herbal medicinal products. This is also supported by the EMA public statement on use of herbal medicinal products containing estragole.
8.4 Estrogenic Activity and Hormone-Sensitive Conditions
Estrogenic activity and antifertility and fetal cell toxicity effects have been shown for trans-anethole (the major constituent of the aniseed essential oil) in rats. Anise might act like estrogen. If a person has any condition that might be made worse by exposure to estrogen, anise should not be used — this includes breast cancer, uterine cancer, ovarian cancer, and endometriosis.
8.5 Use During Pregnancy and Lactation
There are no clinical studies available for use during pregnancy. It is unknown if aniseed and anise oil constituents are excreted in human breast milk. Estrogenic activity and antifertility effects have been shown for trans-anethole in rats. Two young infants were severely intoxicated after ingestion by the mother, used as a galactagogue, of two daily liters of a mixed infusion containing licorice, fennel, anise, and Galega officinalis; symptoms were attributed to anethole from both fennel and anise. High doses of trans-anethole may decrease milk production and induce neurotoxicity along with development of seizures and coma.
8.6 Pediatric Use
Based on safety concerns related to anethole and estragole, the European Medicines Agency (EMA) has disapproved anise preparations for children younger than 12 years old. Case reports have documented seizures in neonates following high maternal intake of anise-containing preparations.
8.7 Neurological Risk at High Doses
P. anisum seeds may interfere with anticoagulant therapy, and the essential oil is contraindicated in individuals with seizures and epilepsy. Although anise has antispasmodic actions in moderate doses, the essential oil can produce tremors and seizures at high doses.
8.8 Drug Interactions
A potential interaction may be supposed, and caution may be useful in case of concomitant use of drugs such as anticoagulants (warfarin) or antiplatelet agents, or other substances or plants influencing blood coagulation.
Increased analgesic effects of codeine and benzodiazepine-induced motor impairment have been observed in mice, and decreased antidepressant effects of imipramine and fluoxetine have been observed with aniseed essential oil pretreatment. Similarly, a pharmacokinetic interaction with acetaminophen and caffeine has been reported in rodents. These interactions have been identified in preclinical models; human pharmacokinetic interaction data are largely absent.
8.9 Quality Adulteration
Problems related to adulteration of anise oil are very common in the real market. Quality control is therefore crucial for this product, and an appropriate set of specifications capable of detecting any adulteration is essential.
References
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