General feature: It is small sized perennial flowering plant that grows tiny yellow flowers. Its matured dry seeds are used in traditional Indian cooking, called Mouri in Bengali and Samchal in Hindi. Fennel is an endogenous wild herbaceous plant native of the Mediterranean regions but later adopted in other parts of the world even in tropics. By nature both plant and seeds are highly aromatic and flavorful, considering the taste it is very close to Anise. The herb, fennel belongs to the family of Apiaceae. The word “Fennel” originates from the old English language either ‘Finol’ or ‘Fenyl’ which is a diminutive of the Latin word ‘Feoeniculum’, meaning ‘hay’. Mostly two types of fennels are commercially available, bitter and sweet. The bulbs, stalks, leaves and matured seeds are normally consumed as foods. The seeds and extracted oil from sweet fennel are used as flavoring agents for foods, drinks, bread and cheese. They are also utilized in cosmetics or pharmaceuticals. As a folk medicine, fennel seeds extracted in water is a classical decoction frequently spoon fed to the babies to prevent the colic pain or flatulence. Besides being used as spice, in many parts of the world, fennel seeds or the extracts are consumed as a traditional medicine for anti-inflammatory, antispasmodic, analgesic, antipyretic, diuretic, galactogogue, secretomotor, antioxidant, secretolytic properties and also as an eye-lotion to treat the viral conjunctivitis.
History: As indicated by history, in the town of Marathon, Athenian used woven Fennel stalks as a sign of victory over the Persians. Further, the legend says that Prometheus brought fire for the human race and hid it inside the stalk of fennel. The Roman philosopher, Pliny described the wonderful property of fennel. According to him, it can take away the film that darkens the human eyes. In ancient India, fennel seeds are chewed for the prevention of any eye problem. The tradition still continues throughout the subcontinent. Besides the Indians, Romans also used it for treating the eye problems. The extract is now used as a potential medicine to treat glaucoma. To the Anglo-Saxon tribe, it was once thought to be a sacred matter. Around 812 AD, the great conqueror Charlemagne introduced fennel as an essential herb, so he installed it in his royal garden for healing many sickness. In England and several European countries, the traditional practice of hanging a fennel plant over the door is still a sign to remove away the evil. During 1200 AD, the fennels are used as appetite suppressant, so ordered by the church for feeding during the fasting days. The practice was continued particularly during long service period to stop the rumbling noise of stomach normally happened in course of fasting. Around 1700 AD the spice found the further use as a medicinal elixir called ‘Absinthe’. Later during the WWI it became highly popular drink all over the Europe and United States. At present fennel seeds are primarily used for culinary purposes although its other uses are still being practiced.
Chemical components: The monograph of European Pharmacopeia shows that sweet fennel seeds has ~ 3 – 6 % of essential oil which has Anethole (~ 50 %), Limonene (40 – 45 %), and Estragole (10 %), Fenchone (~1 %). The oil also has significant quantity of petroselinic acid, oleic acid and tocopherol.
But the contents vary significantly depending on the places of cultivation or season of harvests. It is obvious that most components in the fennel oil are phenylpropanoid derivatives (produced by the metabolism of phenyl alanine) eg; trans – Anethole, Estragole, α – Phellandrene (~ 1.5 %), Fenchone and α – Pinene (~ 1.2 %). Among them trans – Anethole is considered to be a potent anticancer agent.
The other constituents are β – Pinene (~ 1.5 %), β – Myrcene (~1 %) and p – Cymene (~ 0.5 %). Besides, sweet fennel has coumarins and flavonoids as being the nonvolatile components like Isoquercitin – 3 glucuronide, kaempferol – 3 glucuronide, kaempferol – 3 arabinoside. Sweet fennel also contains derivatives of Caffeic and hydroxybenzoic acid.
In addition to those, fennel seeds are composed of ingredients like, carbohydrates (~ 50 g / 100 g), dietary fibers (~ 40 g / 100 g), protein (~ 16 g / 100g) and fat (~ 15 g / 100 g). The seeds also contain good quantity of vitamins like B1, B2, B3, B6 and C. Interestingly, regarding the mineral contents, seeds have high level of Ca (1.2 g / 100 g), K (1.7 g / 100 g) and Mg (0.4 g / 100 g) while the others, Fe, Na, Zn and Mn exist in much lesser level.
Uses: Fennel offers numerous health benefits besides being commonly used as spice in Indian and Mediterranean cuisines. Its bulbs, stalks and leaves or seeds are used to enhance the flavor and nutrition of dishes. In addition to the use of bulb, stalks and leaves as cooked vegetables or raw in salads, the matured dry seeds are routinely used as an essential ingredient of the spice family in many parts of the world due to its pleasant flavor. It has the resemblance of cumin seeds except a greenish tinge in outside appearance. The seeds provide Aniseed flavor, bearing minor sweet taste with nice aroma. In Indian cooking, especially for Bengali cuisines, it is an integral part within five spice mix, traditionally called Panch Phoron. The seed is added to many Mediterranean and Persian cuisines and also used to prepare various cheeses. In India, as a customary, fennel seeds along with cloves and cardamom are chewed after dinner to freshen up the mouth.
Medicinal uses: The seeds or extracts or oil are often used to treat many chronic health problems for its various medicinal and pharmacological roles, particularly applicable to the health of women.
Stimulating lactation and menstruation – The extract of fennel seeds is known to act as a natural galactogogue promoting breast milk production among the nursing mothers. It also helps menstruation for adult females and in addition increases the libido. The active ingredient is identified to be Anethole or more accurately its dimer, di-anethole / photo-anethole enable to mimic the estrogen.
Pregnancy, breast feeding and genital effects – Historically, fennel is known to act as galactogogue to improve the milk productions but it also promotes the growth of female breast tissue. Although physiologically, lactation event does not correlate with the growth of breast. Numerous experiments indicate that the components in fennel act in concerted mechanism as phytoestrogens to exert those effects. On the flip side, it is suspected that too much consumption of fennel extracts / oil by the nursing mothers might cause neurotoxicity in babies. The estrogenous role of fennel extracts / oil are verified through the animal experiments by orally administering to the male rats which show considerable shrinking of testes, vas deferens and prostates, in addition to other associated physiologic changes. At high doses, in young females it induces untimely estrous cycle also causing the vaginal cornification. At higher doses the increment in weight of oviduct, endometrium, myometrium, cervix and vagina is also noticed but at moderate level it enhances the weight of mammary glands. The events confirm the estrogenic role of fennel. The active component is thought to be Photo-anethole but the contribution of others are not ignored.
Effect on dysmenorrhea – Dysmenorrhea occurs due to the abnormally enhanced uterine motility. In addition to severe contraction of the uterus, the event causes tremendous pain due to extreme level of uterine contraction, abnormal menstrual bleeding associated with other physical discomfort. For its long term therapy mix of estrogen and progesterone are applied but to prevent the pain and discomforts nonsteroidal anti-inflammatory drugs (NSAID) are usually prescribed. It is noticed that consumption of fennel seed oil significantly reduces the contractile action which is mediated through the inhibition of Prostaglandin E2. So NSAIDs are helpful by preventing the endogenous PGE2 production and lowering the associated contraction or inflammations. The use of fennel oil once raises a concern regarding teratogenicity (development of congenital embryonic abnormalities). But a significant number of in vitro and in vivo experiments using animal embryos in culture strongly discards that possibility.
Premature thelarche – Thelarche is a disorder causing unusual breast development at the infantile stage especially younger than two years while expressing no sign of puberty. It is associated with the disorders of adrenal, ovarian and hypothyroidism in addition to the use of outside hormones / drugs. The prolong use of fennel seed extracts to control the colic or to eliminate intestinal gas occasionally results in producing premature thelarche. So its use should be kept for a limited period of time.
Common medicinal effects:
Anti-inflammatory, analgesic and antipyretic effect – Oral administration of alcohol extract in bulb mice inhibits acute and subacute inflammations in addition to type IV allergic reactions. The anti-inflammatory actions are seen to be due to the inhibition of both cyclooxygenase (COX) and lipoxygenase (LOX) pathways whereas the analgesic effect is mediated via centrally. The extract significantly increases the level of superoxide dismutase (SOD) and catalase including the rise of HDL concentration in plasma but greatly lowers the level of malondialdehyde (lipid peroxidation indicator). The event confirms that antioxidant effects are also involved in the anti-inflammatory and analgesic actions. It is recorded from the practice that fennel seeds or its water extracts are effective in controlling the pain, inflammation and fever. Experiments on animal confirms its antipyretic role therefore often used in veterinary medicines. The inhibitory actions are identified to be due to mono-terpenes (anethole the most potent one) along with several of the associated antioxidant components (kaempferol, quercetin etc). Fennel oil is seen to potentiate the effect of Mefenamic acid (NSAID and COX inhibitor) without causing any extra complication, to control pain or abdominal muscle cramp during menstruation.
Effect on intestinal problems and colic pain – The spice is particularly favorite for its carminative action to treat flatulence and colic by traditional means which is significantly effective in both children and adults. It works by exerting antispasmodic action. Unlike the drug Dicyclomine (anti-cholenergic muscarinic receptor blocker) causing unwanted side effects to the infants, the fennel extract creates much less adversarial effects. Anethole is suspected to be one of the leading agents. The other uses of fennel seeds and extracts as laxative is already being practiced. The components in spice enhance peristalasis of intestine that essentially prevents the colic pain and perhaps helps by acting as a laxative without imposing any harsh effects. No single compound has been exactly detected in that regard. It is a composite effect and the oil is noticed to serve well.
Effect in eyes – Traditionally in India, matured fennel seeds are eaten raw to improve the eyesight. This practice was also noticed among the ancient Romans. It is a tonic to clear the cloudy eyes. In animal studies it is proven to be a potential medicine to treat the glaucoma. No exact compound has been identified yet.
Anti-cancer effect and associated controversy- Fennel extract is traditionally consumed for maintaining the better health and often labelled as a prevention against the cancers. The presence of high level antioxidants like nevadensin, epigallocatechine and other flavonoids including anethole, a potent anticancer agent is thought to be the underlying cause. But currently, the presence of Estragole raises a deep controversy. Several animal studies identifies the pathway of DNA adduct formation by Estragole alone, which raises the possibility to develop cancers but the event is unnoticed either at low doses or if administered along with any natural matrices like basil. The age old use of fennel never raises this controversy before and so far no incidences of developing any cancers or tumors by its influence is ever been reported. But due to this controversy one should be careful or vigilant for its frequent use. Obviously the large presence of other flavonoids / antioxidants certainly provide significant level of protection in this context. On the contrary, it is proven that the extract of fennel seeds show significant antitumor effects by modulating largely the action of TNF – α, when breast cancer cells (MCF-7) or liver cancer cells (HepG-2) are xenografted in nude mice.
Protection against toxic liver damage – Experiments show that fennel oil prevents / lowers the toxicity in liver during CCl4 induced liver damage in animal model. Although no exact component(s) is identified yet but the possible ones are d – Limonene and β – myrcene.
Several common benefits of fennel:
- Acting as antiseptic – protecting from numerous bacteria particularly in the case of open wound.
- Antispasmodic – Blocks unwanted muscle cramps, contractions of respiratory tract, convulsions, epileptic attacks, muscle pull, intestinal cramps etc.
- Vermifuge – Kills parasitic worms inside intestine.
- Diuretic – Enhances urination also helps excrete various toxic materials built inside the body (Na, Uric acid & bile salt).
- Expectorant – helps remove mucus and phlegm from bronchi, larynx, lungs and nasal tract.
- Tonic – Helps toning all the systems of the body as well as boosting the immune system.