FENNEL

Family: Apiaceae (Umbelliferae), Foeniculum vulgare Mill.

Modified from: Simon, J.E., A.F. Chadwick and L.E. Craker. 1984. Herbs: An Indexed Bibliography. 1971-1980. The Scientific Literature on Selected Herbs, and Aromatic and Medicinal Plants of the Temperate Zone. Archon Books, 770 pp., Hamden, CT.

Fennel, Foeniculum vulgare Mill., is an erect growing perennial herb native to southern Europe and the Mediterranean area. Reaching a height of 1.5 meters, the plant has yellow flowers on a compound umbel. Sweet or Roman fennel is thought to originate from Foeniculum vulgare Mill. subspecies capillaceum (Galib.) Holmboe var. dulce Mill., whereas bitter or wild fennel is from Foeniculum vulgare Mill. subspecies capillaceum (Galib.) Holmboe var. vulgare Mill. (8.2-53). Sweet fennel has also been classified as Foeniculum vulgare Mill. subspecies vulgare var. dulce Batt. and Trab., and as Foeniculum dulce Mill. (14.1-4). The subspecies of bitter fennel has been classified as piperitum rather than capillaceum (4.3-38). Principal fennel production areas are located in India, the People's Republic of China, Egypt, Argentina, Indonesia, and Pakistan. The word foeniculum is from the latin word for fragrant hay, reflecting the plant's odor (11.1-14.1-3).

The reported life zone of fennel is 4 to 27 degrees centigrade with an annual precipitation of 0.3 to 2.6 meters and a soil pH of 4.8 to 8.3 (4.1-31). Fennel thrives on well drained loam soil.

Although a perennial, fennel is generally grown as an annual or biennial crop. Yields of the dried fruit, commonly thought of as fennel seed, are low in the first year but increase in the second. The umbels do not mature uniformly, and several harvests are therefore necessary to maximize yield. Mechanical harvesting of commercial stands must be carefully timed to obtain high yields. Approximately 60 percent of the essential oil is located in the fruit, with the rest in the rays of the umber and other green plant parts.

The oils of both sweet and bitter fennel seed, obtained by steam distillation, contain anethole, fenchone, -pinene, camphene, -pinene, sabenine, myrcene, -phellandrene, limonene, cis-ocimene, para-cymene, camphor, and several other volatile constituents as well as a fixed oil (8.2-53). Bitter fennel oil is thought to contain more fenchone (a bitter mixture with a camphor-like odor and flavor) and less anethole than sweet fennel oil. Sweet fennel oil is of a superior quality with a more pleasing aroma and flavor (14.1-9). Some analyses have indicated a lack of fenchone in sweet fennel and high concentrations of limonene in bitter fennel (8.2-53).

Fennel seed is used in the food and flavor industry for addition to meats, vegetable products, fish sauces, soups, salad dressings, stews, breads, pastries, teas, and alcoholic beverages. Crushed seed has been used as a substitute for juniper in flavoring gin. The essential oil and the oleoresin of fennel are used in condiments, soaps, creams, perfumes, and liqueurs. Several types of fennel differing in morphology and leaf color are available for ornamental use and as a fresh vegetable.

As a medicinal plant, fennel seed has been used as an antispasmodic, carminative, diuretic, expectorant, laxative, stimulant, and stomachic. Fennel has also been used to stimulate lactation, as a remedy against colic, and to improve the taste of other medicines. Chinese herbal medicine includes the use of fennel for gastroenteritis, hernia, indigestion, abdominal pain, and to resolve phlegm and stimulate milk production (11.1-10). Fennel is known to provoke both photodermatitis and contact dermatitis in humans (11.1-96). The volatile oil may cause nausea, vomiting, seizures, and pulmonary edema (1.8-100). The essential oil has been reported to stimulate liver regeneration in rats (7.6-57) .

Foeniculum vulgare Mill. subspecies vulgare or capillaceum var. azoricum (Mill.) Thell. is known as Florence or finocchio fennel. This plant has a thickened base of leaves, which can be blanched or boiled and eaten as a vegetable. Common giant fennel, a robust plant 2 to 4 meters high and cultivated for its yellow flowers, is actually Ferula communis L., another member of the Apiaceae family (14.1-3).

Fennel is generally recognized as safe for human consumption when used as a spice/natural flavoring or as an essential oil/oleoresin (21 CFR sections 182.10, 182.20 [1982]).

[Note: References listed above in parentheses can be found in full in the original reference].


Aromatic and Medicinal Plants Index

Last modified 6-Dec-1997