Fennel is a tall perennial herb native to the Mediterranean region, now widely cultivated as an annual or perennial in Bulgaria, Romania, Hungary, Greece, Turkey, Italy, France, Germany, Egypt, India, and China (Bruneton, 1995; Grieve, 1979; Leung and Foster, 1996; Wichtl and Bisset, 1994). Fennel is one of Germany's more important medicinal plant crops (Lange and Schippmann, 1997). The material of commerce comes mainly from Bulgaria, Hungary, Romania, Egypt, and China (BHP, 1996; Wichtl and Bisset, 1994).
Its modern therapeutic uses in Germany and the United States stem from traditional Greek medicine as practiced by Hippocrates and later by Dioscorides. It is still widely used in traditional Arabian medicine as a diuretic, appetizer, and digestive (Tanira et al., 1996). Its original Greek genus name was Marathron, from maraino, meaning to grow thin. Its current genus name, Foeniculum, was assigned by the Romans, derived from the Latin word foenum, meaning hay (Grieve, 1979). Fennel's therapeutic uses have been introduced and integrated into many other systems of traditional medicine, including Ayurvedic, Chinese, and Japanese Kampo. For example, the present Ayurvedic Pharmacopoeia recommends it in dried fruit or fluidextract form, for flatulent dyspepsia, anorexia, and flatulent colic in children (Karnick, 1994). Its indications for use in the present Chinese pharmacopoeia include for distending pain in the epigastrium with anorexia, dysmenorrhea with lower abdominal pain and cold sensation, vomiting, and diarrhea (Tu, 1992).
The modern therapeutic applications for fennel seed and oil are supportable based on their history of use in well established systems of traditional medicine, phytochemical investigations, and in vitro and in vivo studies in animals.
In Germany, fennel seed is licensed as a standard medicinal tea for dyspepsia. It is also used in cough syrups and honeys (antitussives and expectorants), and stomach and bowel remedies, especially in pediatrics, as aqueous infusion, water (Aqua Foeniculi), drage (lozenge), juice, and syrup. It is often used in combination with aniseed (Leung and Foster, 1996; Wichtl and Bisset, 1994). In the United States, it is also used as a component of galactagogue preparations. Indications for use of fennel oil are similar to those for fennel seed. In Germany and the United States, fennel oil is used as an expectorant component of cough remedies, and also as a carminative component of stomach and bowel remedies in dosage forms including honey and syrup. Traditionally, it is combined with laxative or purgative herbs to counteract or modify their harsh griping effects in the bowels (ESCOP, 1997; Leung and Foster, 1996; Nadkarni, 1976; Wichtl and Bisset, 1994). The Commission E limits the use of fennel seed and fennel oil for up to two weeks and then recommends consulting a physician.
Pharmacopeial grade bitter fennel seed must contain not less than 4% (v/m) total volatile oils, calculated with reference to the anhydrous drug, as determined by the European Pharmacopoeia (Ph.Eur.3) method 2.8.12. Its volatile oil must be composed of not less than 60% anethole, not less than 15% fenchone, and maximum 5% estragole, as determined by Ph.Eur.3 GC method 2.2.28 (DAB 10, 1991; ESCOP, 1997; Ph.Eur.3, 1997). The Austrian Pharmacopoeia requires not less than 3.5% volatile oil ( AB, 1981-1983).
The official fennel oil of the European Pharmacopoeia is derived from bitter fennel (var. vulgare) as opposed to sweet fennel (var. dulce). Pharmacopeial grade fennel oil must be composed of not less than 60% anethole, not less than 15% fenchone, and no more than 5% estragole, as determined by Ph.Eur.3 GC method 2.2.28 (Ph.Eur.3, 1997).The relative proportions of its main constituents determine its overall bitterness or sweetness. Fenchone has a disagreeable bitter taste; anethole is sweet (Bown, 1995; Grieve, 1979). The relative ratios of these components and their yields vary somewhat by strain and region. Historically, the strains yielding oils most suitable for pharmaceutical use have been Russian, Saxon, Galician, and Romanian (Bown, 1995; Grieve, 1979; Nadkarni, 1976). As the ratio of its main components determine the pharmaceutical quality of the oil, long-term studies investigated the production—the biological and structural regularities of essential oil accumulation in developing fruits of bitter fennel. In a study of 13 different plant populations, representing three different chemovarieties (e.g., cv. 'Soroksári'), the presence and ratio of anethole, methyl-chavicol, and fenchone were analyzed and found to be stable throughout nine stages of flowering and fruiting (Bernáth et al., 1998).
Description
Fennel oil is the essential oil obtained from the dried, ripe fruits of Foeniculum vulgare Miller var. vulgare (Miller) Thellung [Fam. Apiaceae] by steam distillation and its preparations in effective dosage. Fennel oil contains anethole, fenchone, and not more than 5% estragole.
Chemistry and Pharmacology
Fennel essential oil contains trans-anethole (5070%), (+)-fenchone (922%), and estragole [methyl chavicol] (25%). Other compounds in the oil include anisaldehyde, camphene, fenchyl alcohol, limonene, ρ-anisic acid, 3-carene, ρ-cymene, α-fenchene, β-myrcene, α-pinene, β-pinene, α-phellandrene, sabinene, α- and β-terpinene, γ-terpinene, terpinolene, α-thujene, cis- and trans-ocimenes, trans-1,8-terpin (Bruneton, 1995; ESCOP, 1997; Leung and Foster, 1996; Wichtl and Bissett, 1994).
The Commission E reported stimulation of gastrointestinal motility activity that, in higher concentrations, was antispasmodic. Experimentally, anethole and fenchone have shown a secretolytic action on the respiratory tract. In vitro, fennel oil has demonstrated antimicrobial activity.
Volatile oil of fennel seed has demonstrated carminative and stimulant activities as well as spasmolytic actions on the smooth muscles of experimental animals (Leung and Foster, 1996). Fennel syrup and fennel honey reduced spasms induced by acetylcholine and barium chloride in vitro in isolated guinea pig ileum though weaker than the effects of an aqueous infusion of bitter fennel seed (ESCOP, 1997).
Uses
The Commission E approved the internal use of fennel oil preparations for peptic discomforts, such as mild, spastic disorders of the gastrointestinal tract, feeling of fullness, and flatulence; and also for catarrhs of the upper respiratory tract. Fennel honey was recommended for catarrhs of the upper respiratory tract in children.
ESCOP approves the use of fennel syrup or fennel honey for catarrh of the upper respiratory tract in children (ESCOP, 1997).
Contraindications
Fennel honey: None known.
Other preparations: Pregnancy. Not to be used for infants and toddlers.
Side Effects
In rare cases, allergic reactions affecting skin and respiratory system.
Use During Pregnancy and Lactation
No restrictions known for fennel honey. Other fennel oil preparations not recommended during pregnancy. No restrictions known during lactation.
Interactions with Other Drugs
None known.
Dosage and Administration
Unless otherwise prescribed: 0.1-0.6 ml essential oil or equivalent galenical preparations for internal use.
Essential oil: 0.1-0.6 ml.
Fennel honey or fennel syrup with 0.5 g fennel oil/kg [=0.5:1000 (w/w)]:
Adult: 10-20 g.
Children 4-10 years: 6-10 g.
Children 1-4 years: 3-6 g.
Duration of administration: Unless otherwise advised by a physician or pharmacist, one should not consume fennel oil for an extended period (several weeks).
Note:Fennel syrup, fennel honey: Diabetics must consider sugar content of bread exchange units according to manufacturer's information.
References
Bernáth, J. et al. 1998. Production-biological and structural regularities of essential oil accumulation in developing fruits of fennel (Foeniculum vulgare Mill.). Budapest: UHFI Department of Medicinal Plant Production.
Bown, D. 1995. Encyclopedia of Herbs and Their Uses. New York: DK Publishing, Inc. 283-284.
British Herbal Pharmacopoeia (BHP). 1996. Exeter, U.K.: British Herbal Medicine Association.
Bruneton, J. 1995. Pharmacognosy, Phytochemistry, Medicinal Plants. Paris: Lavoisier Publishing.
Deutsches Arzneibuch, 10th ed. (DAB 10). 1991. (With subsequent supplements through 1996.) Stuttgart: Deutscher Apotheker Verlag.
ESCOP. 1997. 'Foeniculi aetheroleum' and 'Foeniculi fructus.' Monographs on the Medicinal Uses of Plant Drugs. Exeter, U.K.: European Scientific Cooperative on Phytotherapy.
Grieve, M. 1979. A Modern Herbal. New York: Dover Publications, Inc.
Karnick, C.R. 1994. Pharmacopoeial Standards of Herbal Plants, Vols. 12. Delhi: Sri Satguru Publications. Vol. 1:139141; Vol. 2:71.
Lange, D. and U. Schippmann. 1997. Trade Survey of Medicinal Plants in GermanyA Contribution to International Plant Species Conservation. Bonn: Bundesamt für Naturschutz. 32-33.
Leung, A.Y. and S. Foster. 1996. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics, 2nd ed. New York: John Wiley & Sons, Inc.
Nadkarni, K.M. 1976. Indian Materia Medica. Bombay: Popular Prakashan. 557-559.
Tanira, M.O.M. et al. 1996. Pharmacological and toxicological investigations on Foeniculum vulgare dried fruit extract in experimental animals. Phytother Res 10:33-36.
Tu, G. (ed.). 1992. Pharmacopoeia of the People's Republic of China (English Edition 1992). Beijing: Guangdong Science and Technology Press. 70.
Wichtl, M. and N.G. Bisset (eds.). 1994. Herbal Drugs and Phytopharmaceuticals. Stuttgart: Medpharm Scientific Publishers.
Additional Resources
Betts, T.J. 1968. Anethole and fenchone in the developing fruits of Foeniculum vulgare Mill. J Pharm Pharmacol 20(6):469-472.
Boyd, E.M. and E.P. Sheppard. 1968. The effect of steam inhalation of volatile oils on the output and composition of respiratory tract fluid. J Pharmacol Exp Ther 163(1):250-256.
—. 1971. An autumn-enhanced mucotropic action of inhaled terpenes and related volatile agents. Pharmacology 6(2):65-80.
Food Chemicals Codex, 2nd ed.(FCC II).1972. Washington, D.C.: National Academy of Sciences.
Hänsel, R., K. Keller, H. Rimpler, G. Schneider (eds.). 1993. Hagers Handbuch der Pharmazeutischen Praxis, 5th ed. Vol. 5. Berlin-Heidelberg: Springer Verlag. 156-181.
Kapoor, L.D., A. Singh, S.L. Kapoor, S.N. Srivastava. 1969. Survey of Indian plants for saponins, alkaloids and flavonoids. Lloydia 32(3):297-304.
List, P.H. and L. Hörhammer (eds.). 1973-1979. Hagers Handbuch der Pharmazeutischen Praxis, Vols. 17. New York: Springer Verlag.
Madaus, G. 1976. Lehrbuch der Biologischen Heilmittel. Vol. 2. Hildesheim; New York: Georg Olms. 1354-1361.
Marsh, A.C. et al. 1977. Composition of Foods, Spices, and Herbs: Raw, Processed, Prepared. Agriculture Handbook No. 82. Washington, D.C.: Agricultural Research Service, U.S. Department of Agriculture.
Maruzzella, J.C. and M. Freundlich. 1959. Antimicrobial substances from seeds. J Am Pharm Assoc 48:356-358.
Maruzzella J.C. and N.A. Sicurella. 1960. Antibacterial activity of essential oil vapors. J Am Pharm Assoc 49:692-694.
McGuffin, M., C. Hobbs, R. Upton, A. Goldberg. 1997. American Herbal Product Association's Botanical Safety Handbook. Boca Raton: CRC Press.
Ramadan, F.M., R.T. el-Zanfaly, F.A. el-Wakeil, M. Alian. 1972. On the antibacterial effects of some essential oils. I. Use of agar diffusion method. Chem Mikrobiol Technol Lebensm 2:51-55.
Reynolds, J.E.F. (ed.). 1993. Martindale: The Extra Pharmacopoeia, 30th ed. London: The Pharmaceutical Press. 1369-1370.
Steinegger, E. and R. Hänsel. 1992. Pharmakognosie, 5th ed. Berlin-Heidelberg: Springer Verlag.
Yen, K.Y. 1992. The Illustrated Chinese Materia Medica—Crude and Prepared. Taipei: SMC Publishing, Inc. 133.
This material was adapted from The Complete German Commission E Monographs—Therapeutic Guide to Herbal Medicines. M. Blumenthal, W.R. Busse, A. Goldberg, J. Gruenwald, T. Hall, C.W. Riggins, R.S. Rister (eds.) S. Klein and R.S. Rister (trans.). 1998. Austin: American Botanical Council; Boston: Integrative Medicine Communications.
1) The Overview section is new information.
2) Description, Chemistry and Pharmacology, Uses, Contraindications, Side Effects, Interactions with Other Drugs, and Dosage sections have been drawn from the original work. Additional information has been added in some or all of these sections, as noted with references.
3) The dosage for equivalent preparations (tea infusion, fluidextract, and tincture) have been provided based on the following example:
Unless otherwise prescribed: 2 g per day of [powdered, crushed, cut or whole] [plant part]
Infusion: 2 g in 150 ml of water
Fluidextract 1:1 (g/ml): 2 ml
Tincture 1:5 (g/ml): 10 ml
4) The References and Additional Resources sections are new sections. Additional Resources are not cited in the monograph but are included for research purposes.
This monograph, published by the Commission E in 1994, was modified based on new scientific research. It contains more extensive pharmacological and therapeutic information taken directly from the Commission E.
Excerpt from Herbal Medicine: Expanded Commission E Monographs Copyright 2000 American Botanical Council Published by Integrative Medicine Communications Available from the American Botanical Council.