What is Fennel Essential Oil?

Fennel essential oil is a volatile extract obtained by steam distillation of the seeds of Foeniculum vulgare Mill. (sweet fennel). It has a thin consistency and is light in color with a faint yellow tint.

Aromatically classified as top to middle note, fennel essential oil is sweet, yet somewhat spicy and peppery with a licorice-like aniseed aroma.

The essential oil of fennel blends well with essential oils of angelica, basil, lavender, coriander, clary sage, marjoram, sandalwood, rosemary, peppermint, cardamom, ginger, turmeric, grapefruit, bergamot, orange, mandarin, ylang ylang, rose and geranium.

Native to the Mediterranean basin, fennel has been introduced to and naturalized across Eur-Asia, India and North America, adapting to most temperate climates.

Nowadays, it is mainly grown and distilled in France, Spain, Germany, Hungary and India for its essential oil.

About Fennel (Foeniculum Vulgare M.)

Foeniculum vulgare Mill. Commonly known as fennel or sweet fennel, is a flowering medicinal plant belonging to the family Apiaceae (Umbelliferae). It is a hardy, perennial herb with yellow flowers and feathery leaves.

Fennel is a very aromatic and tasty herb and, both along with the similar flavor anise, are part of the main ingredients of the legendary highly alcoholic beverage absinthe.

Fennel is commercially cultivated in Egypt and grows wild in many areas of the Egyptian desert. It is represented in Egypt by two fennel types: sweet fennel, (Foeniculum vulgare Mill. subsp. vulgare) and bitter fennel (Foeniculum vulgare subsp. Piperitum).

Also, it is widely cultivated throughout the temperate and tropical regions of the world due to its aromatic fruits, which are used as culinary spices.

The F. vulgare fruit has a long history of use as both a food and medicine. Mature fruit of the plant and its essential oil are used as flavoring agents in food products such as liqueurs, bread, pickles, pastries, and cheese.

Traditionally, it is said to act as a carminative (assists with flatulence control), increase breast milk production and for treating female infertility.

They are also used as a constituent in cosmetic and pharmaceutical products.

Additionally, fennel is well known in traditional medicine for its antiseptic, palliative and anti-inflammatory effects.

The many uses of fennel in history

Fennel is considered as one of the oldest medicinal plants and culinary herbs. It have been used over 4000 years. Ancient Egyptians used it as a food and medicine, and it was considered as an antidote for snake bites in ancient China.

Also, it was used since ancient times to treat menstrual disorders, dyspepsia, flatulence and cough, and to reduce the griping effect of laxatives.

Foeniculum vulgare was widely applied in traditional Arabian medicine as diuretic, aperitive, and digestive. The fruit, seeds and young leaves were used for flavoring sweet dishes and confectionery. Also, the young leaves, raw or cooked, were used as flavoring agent.

The seeds have an anise-like flavor and they are widely used as a flavoring as well. Besides, the fruits were used as carminative and the roots, as purgative.

Crushed fruits were inhaled to counter faintness, While Infusion of fruit was used for flatulence.

Chemical Compounds of Fennel Essential Oil

The chemical composition of fennel essential oil from different geographical locations has been extensively studied. According to these studies, the major components of fennel oil are: trans-anethole, estragole, fenchone, and limonene depending on the chemotype.

However, the most important compounds in fennel essential oil are: trans-anethole, limonene, eugenol, estragole, fenchone, α-pinene, camphene, β-pinene, β-myrcene, α-phellandrene, β-ocimene Z, β-ocimene, α-fenchyl acetate, β-fenchyl acetate, cis-anethole, α-copaene, β-farnesene and germacrene-D.

Properties of Fennel Essential Oil

Fennel essential oil exhibits antispasmodic, carminative, anti-inflammatory, diuretic, digestive, laxative, vermifuge, cytotoxic, antimicrobial, bronchodilatory, lithontripic, hypotensive, gastroprotective, memory enhancing, antimutagenic, aperitive, expectorant, antiseptic, analgesic and estrogenic activities.

In vitro, fennel oil possesses antioxidant, antimicrobial, insecticidal, anti-thrombotic and hepatoprotective effects. Furthermore, the essential oil of fennel exhibits in vitro anticancer activity.

Recently it was shown that fennel essential oil possesses reproductive, urinary, antidiabetic, cardiovascular, immunological, dermatological, emmenagogue and galactagogue properties, and is a cure for pediatric colic and respiratory disorders, due to its antispasmodic properties.

Uses of Fennel Essential Oil

In traditional medicine, the plant and its essential oil have been extensively used as carminative, digestive, galactogogue and diuretic and to treat respiratory and gastrointestinal disorders.

Essential oil of fennel is used as flavoring agents in food products such as beverages, bread, pickles, pastries, and cheese. It is also used as a constituent of cosmetic and pharmaceutical products.

Among the most common therapeutic uses of fennel essential oil are:

Helps to heal wounds and prevents them from becoming infected.
Regulates menstrual period and relieves its symptoms.
Relieves cramps and respiratory, gastrointestinal, abdominal, muscular and nervous spasms.
Helps to control seizures caused by epilepsy.
Promotes good digestion and relieves constipation.
Eliminates intestinal parasites.
Stimulates urination, promoting the elimination of toxins from the body.
Reduces blood pressure.
Natural laxative for chronic and acute constipation problems.
Relieves nausea and vomiting.
Stimulates the proper functioning of all systems in our body.
Helps fight fatigue and depression.
Protects the stomach from ulcers and infections.
Excellent bloody depurative.
Because of its diuretic activity, it is useful for kidney and bladder diseases.
Treatment for chronic cough and bronchopulmonary congestion.
Promotes positive thoughts and creativity.
Improves mood and provides strength and courage to face difficult situations.
Stimulates the production of breast milk.
Delays the premature aging of our tissues, attenuates wrinkles and lines of expression, helping to tone and beautify our skin.
Reduces swelling under the eyes.
Supplements weight loss treatments, since it helps suppress appetite.
Home treatment to increase breast size and attenuate cellulite.
Controls stress, psychological disturbances and other idiopathic causes.
Alleviates digestive disorders, dyspepsia, flatulence, etc.
Helps relieve the symptoms of irritable bowel syndrome.
Natural fertility treatment.
Soothes menopausal symptoms.
Relieves tired and heavy legs.
Eliminates fluid retention.

Benefits of Fennel Essential Oil

Antibacterial Activity

Fennel essential oil exhibited antibacterial effect against foodborne pathogens such as Bacillus megaterium and Listeria monocytogenes.

Also, it exhibited in vitro strong inhibitory activities against the growth of a wide spectrum of bacteria and fungi known to be pathogenic for man and other species.

Earlier studies also demonstrated the antibacterial activity of the oil. Fennel oils was found to have a high antibacterial activity and inhibited the growth of a range of bacteria including:

Escherichia coli (responsible for urogenital tract infections and diarrhea)
Staphylococcus aureus (responsible for bases, sepses and skin infections)
Streptococcus haemoliticus (causing infection of the throat and nose)
Bacillus subtilis (infection in immunecompromised patients)
Candida albicans
Salmonella typhimurium
Brevibacterium linens
Clostridium perfringens
Leuconostoc cremoris
Pseudomonas aeruginosa (causing hospital acquired infection)
Klebsella species
Proteus vulgaris

Antioxidant and Cytotoxic Activity

Based on the data obtained from some studies, fennel essential oil exhibits ability as a free radical inhibitor or scavenging activity, as well as primary antioxidant that reacts with free radicals, which may limit free radicals damage occurring in the human body.

It has shown antioxidant, cytotoxic, and anti-tumor activities in animal models. Its ethanol extract was shown to be highly significant in inducing apoptosis in two leukemic cell lines C8166 and J45.

In a study investigating antioxidant properties of different parts of F. vulgare, the shoots had the highest radical scavenging and lipid peroxidation inhibiting activity.

Despite of these positive reports, the results of a study on different fractions of fruit and their major chemical compounds did not show strong antioxidant activities from isolated F. vulgare component.

Anti-inflammatory Activity

Oral administration of F. vulgare fruit methanol extract to rat and mice exhibited inhibitory effects against acute and subacute inflammatory diseases and type Ⅳ allergic reactions and showed a central analgesic activity.

Cardiovascular and Antithrombotic Effects

Fennel essential oil and its main component anethole, inhibited arachidonic acid-, collagen-, ADP- and U46619-induced platelet aggregation (IC50 from 4 to 147 microg/ml).

Anethole also prevented thrombin-induced clot retraction at concentrations similar to fennel oil.

The essential oil and anethole, tested in rat aorta with or without endothelium, displayed comparable NO-independent vasorelaxant activity at the same antiplatelet concentrations, which have been proved to be free from cytotoxic effects in vitro.

On the other hand, in vivo, both fennel essential oil and anethole, orally administered in a subacute treatment to mice (30 mg/kg/day for 5 days) showed significant antithrombotic activity, preventing the paralysis induced by collagen-epinephrine intravenous injection (70% and 83% protection, respectively).

At the antithrombotic dosage, they were free from prohemorrhagic side effect.

Bronchodilatory Effect

Ethanol extract and essential oil from F. vulgare exhibited bronchodilatory activity on contracted tracheal chains of guinea pig. The potassium channel opening effect of plant may contribute on its relaxant effect on guinea pig tracheal chains.

Estrogenic Properties

Fennel has estrogen-like activity. In female rats, oral administration of the extract for 10 days led to vaginal cornification and oestrus cycle. While moderate doses caused increase in weight of mammary glands, higher doses increased the weight of oviduct, endometrium, myometrium, cervix and vagina also.

Also, the essential oil of fennel has demonstrated beneficial effects in primary dysmenorrhea. Its efficacy on reducing or relieving pain of dysmenorrhea is comparable to mefenamic acid.

Fertility Enhancing Activity

In 2011, a study published in the International Journal of Fertility & Sterility, elucidated the fact that fennel oil has a folliculogenesis effect in female mice consistent with its use in folk medicine as a fertility enhancing agent.

Further studies are suggested for understanding the exact mechanism underlying these actions and probable changes in hormonal levels.

Hypolipidemic Activity and Effect on Body Weight

The effect of fennel essential oil in high fat diet and their possible role in obesity and associated cardiovascular disorders were studied in rats.

Three fractions prepared by successive solvent technique from methanol extract of fennel fruits were administered at a dose of 300 mg/bw by oral gavage, and fennel essential oil at a dose of 0.2 ml/bw intraperitoneally once a day, along with high fat diet; to the female albino rats for six weeks.

Results revealed that body weight and fat pad weights were reduced in extracts fed animals in a variable pattern.

On the other hand, cholesterol and triglycerides levels, which were elevated in high fat diet fed animals, improved in a significant manner.

Hepatoprotective Effect

In 2010, a study conducted at the National Research Center in Egypt, showed that fennel essential oil appeared to be effective in its protection against hepatotoxic effects, due to its higher content of different antioxidants and its ability to scavenge free radicals.

Administration of oil via oral route, more closely mimics a potential route of exposure, where fennel oil might be administered as tablets (or syrup) or by adding it to “functional foods”.

Also, the hepatoprotective activity of steam distilled essential oil from fennel was studied in 2003 by Ozbek et al. by using the carbon tetrachloride induced acute liver injury model in rats.

In addition, when simultaneously administered with carbon tetrachloride, fennel oil significantly reduced hepatotoxicity as shown by the decreased levels of serum aspartate amino-transferase, alanine aminotransferase, alkaline phosphatase and bilirubin.

These results were confirmed by Ozbek et al. in 2004. Through the administration of fennel oil in rats, a few times a week, for seven weeks.

The study evaluated the above-mentioned biochemical markers as well as rat body weight and liver histopathology.

Antidiabetic Effect

The antiglycation properties of methanolic extracts of 23 fennel samples were evaluated in the bovine serum albumin (BSA)/glucose system. The level of glycation, conformational alterations and protein binding to RAGE receptors were assessed by Congo red binding assay and a brown staining method. Some samples showed high anti-glycative activity.

However, although the results are encouraging, more research is still needed.

Central Nervous System (CNS) Activity

The anxiolytic, anti-stress and memory-enhancing activities of fennel essential oil were studied in mice using different types of test. In all of them, the promising and important efficacy of fennel oil administered to mice was observed.

For example, when studying the anxiolytic activity of fennel essential oil, the effect produced by the extract was comparable to that of diazepam, but without side effects.

On the other hand, the antidepressant effect of Fennel and Vetiver essential oils in comparison with antidepressant drug fluoxetine was investigated in depressive behavior in albino rats. Both Forced swimming test and Tail suspension test were used for screening antidepressant effect.

The ethanolic extract of fennel and vetiver together, fluoxetine and saline were administered 30 minutes prior to the tests, and the immobility period was recorded for 6 minutes.

Fennel essential oil and vetiver essential oil produced significant antidepressant effect by reduction in immobility period as compared to control. But when given both together they were equally effective as fluoxetine.

Warnings and Precautions When Using Fennel Essential Oil

Toxicity of Fennel Essential Oil

Fennel essential oil, in its composition, has a high content of estragole and anethole, which can create a narcotic effect and cause complications in the respiratory system, as well as seizures and hallucinations if consumed in inadequate doses.

A manifestation due to excessive consumption of fennel oil, is acceleration of the heartbeat.

On the other hand, in high doses, fennel oil could stimulate a high production of thyroid hormones, which can trigger hyperthyroidism.

If excessive doses are ingested, the estrogenic activity of fennel oil may affect hormone therapy, including the oral contraception and hormone replacement therapy.

However, no levels of toxicity have been found in fennel oil when used in adequate doses.

Fennel Essential Oil and Epilepsy

People suffering from epilepsy should avoid the consumption of fennel oil. However, by inhalation, this can help calm possible seizures.

Seizure disorders are contraindicated for some, although Tisserand does not directly contraindicate fennel for seizures. However, levels of sensitivity may vary person to person.

Contraindications

Diabetic patients, hemophiliacs and/or under treatment with anticoagulants, should avoid the use of this oil.

Fennel essential oil should be avoid for patients suffering from endometriosis, and estrogen dependent cancers, since trans-anethole exhibits estrogenic actions.

Persons with hypersensitivity to the active substance, to Apiaceae (Umbelliferae) (aniseed, caraway, celery, coriander and dill), or to anethole, should avoid the use of fennel preparations and fennel oil.

Essential oils with estragole (Methyl chavicol) should also be used carefully (especially internally) for its effect on the blood.

Special Warnings and Precautions

Due to its trans-anethole content, fennel essential oil should be avoided by any route (method of application, especially oral) in pregnancy and breastfeeding periods.

The use of fennel oil in children and adolescents under 18 years old is contraindicated, because of the lack of data, and the presence of estragole.

Preparation with high fennel content (> 7 g of herbal substance) should not be taken for more than two weeks without medical advice.

Undesirable effects

Allergic reactions to fennel, affecting the skin or the respiratory system, occur rarely.
Rare cases of contact dermatitis to anethole containing preparations have been reported.
It has been observed that fennel contains coumarin-derivatives, which competitively can inhibit vitamin K and may interfere with blood clotting.
Fennel contains small amounts of bergapten, a linear furocoumarin that might be responsible for phototoxicity.

Where to buy Fennel Essential Oil?

Normally, good quality oils, can be found in specialized natural herb stores. If you can not reach a trusted naturist or herbalist shop near you, here are some recommendations:

Fennel, Sweet Essential Oil

Scent Characteristics: Sweet, somewhat spicy and peppery, with a licorice-like aroma.

Our 100% Pure Essential Oils are extracted from the root, bark, wood, seed, fruit, leaf, or flower of a freshly harvested plant.
We source only the finest quality essential oils from highly regarded suppliers and distillers from around the world, many with whom we’ve worked with for decades.
Many of our oils are steam-distilled or cold-pressed, therefore retaining the essential odor, aroma, taste, medicinal, and therapeutic properties of the plant, resulting in a superior quality, and highly concentrated essence. Shop here.

Tips for a better performance and duration of your oils:

Store them in a dark glass bottle, never plastic, not even when blended with a carrier oil.
Keep them in cool, dark places, away from sources of heat and light.
Maintain the container that holds it tightly closed, since they are very volatile and also, their properties would be lost or modified.