General Description
Licorice is a perennial legume native to the Mediterranean region
and southwest Asia and cultivated throughout much of Europe, Asia,
and the southwestern United States. The plant has an erect, striated
stem, reaching up to one meter in height, bearing alternate, compound,
pinnate leaves with four to eight pairs of smooth, dark green leaflets,
two to five centimeters long. Licorice flowers in midsummer, with
clusters of purple or yellowish-white flowers which are followed
by small, one-celled pods containing one to six kidney-shaped seeds.
The root of the plant, which may reach up to 1 1/2 meters in length,
is used medicinally and as a flavoring agent for foods, confections,
drugs, and tobacco.
Health Applications
- Liver health
- Gastrointestinal health
- Respiratory health
History and Traditional Use
Licorice has a history of medicinal use dating back over 2,000 years.
In the third century B.C., Theophrastus mentions the root and its
use as a remedy for asthma, cough, and chest ailments.1
In the 17th century, British herbalist Nicholas Culpeper prescribed
the root for a variety of respiratory and urinary tract ailments
and for topical use for "eyes that have a pin and web."2
Chemical Composition
Licorice root contains a saponin glycoside compound called glycyrrhizin
(also known as glycyrrhizic acid), which is considered the most
active ingredient.3 Chemical analysis of licorice
root has revealed 15 distinct saponins and at least 49 flavonoids.4
Contemporary Uses
Germany's Commission E lists licorice root as an approved herb
for treatment of upper respiratory tract ailments and for gastric
or duodenal ulcers.5 Several studies suggest
that glycyrrhizin may be useful in treatment of hepatitis B,5-11
and possibly hepatitis C;13 however, most
in vivo studies on human subjects have used intravenous licorice
formulations, and the effectiveness of oral licorice formulations
for these purposes has not been demonstrated. While studies indicate
that licorice root has anti-ulcer properties,13-16
these effects are not attributed to glycyrrhizin, but rather to
several nonacidic compounds found in the herb.17
For this reason, many herbalists recommend deglycyrrhized forms
of the herb for ulcers and other gastrointestinal complaints.
While licorice is commonly used to treat coughs and inflammation
of the upper respiratory tract, there is little scientific evidence
to support such use.
Dosage/Toxicity
The daily dosage approved by Commission E is 5 to 15 grams of
whole root or preparations supplying 200 to 600 mg of glycyrrhizin.5
For deglycyrrhized licorice extracts (DGL), a common recommendation
is two to four 380 mg chewable tablets 20 minutes before meals.18
Because excessive consumption of glycyrrhizin can cause potassium
depletion,19 licorice root is not recommended
for people taking digitalis or anyone with hypertension or kidney
disease. Licorice root should not be used during pregnancy or
by people with liver cirrhosis or cholestatic liver disorders.5
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