| Liquorice | |
|---|---|
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Fabales |
| Family: | Fabaceae |
| Subfamily: | Faboideae |
| Tribe: | Galegeae |
| Genus: | Glycyrrhiza |
| Species: | G. glabra |
| Binomial name | |
| Glycyrrhiza glabra L.[1] |
|
| Synonyms | |
Liquorice or licorice (/ˈlɪkᵊrɪʃ/ lik-(ə-)rish or /ˈlɪkᵊrɪs/ lik-(ə-)ris)[2] is the root of Glycyrrhiza glabra from which a somewhat sweet flavour can be extracted. The liquorice plant is a legume (related to beans and peas) that is native to southern Europe and parts of Asia. It is called "Mulethi" in Northern India. It is not related to anise, star anise, or fennel, which are the sources of similar-tasting flavouring compounds.
It is a herbaceous perennial, growing to 1 m in height, with pinnate leaves about 7–15 centimetres (3–6 in) long, with 9–17 leaflets. The flowers are 0.8–1.2 cm (½–⅓ in) long, purple to pale whitish blue, produced in a loose inflorescence. The fruit is an oblong pod, 2–3 centimetres (1 in) long, containing several seeds.[3] The roots are stoloniferous.[4] The flavor of liquorice comes mainly from a sweet-tasting compound called anethole ("trans"-1-methoxy-4-(prop-1-enyl)benzene), an aromatic, unsaturated ether compound also found in anise, fennel, and several other herbs. Much of the sweetness in liquorice comes from glycyrrhizin, a compound sweeter than sugar.
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Liquorice grows best in deep valleys, well-drained soils, with full sun, and is harvested in the autumn, two to three years after planting.[3]
Today, liquorice extract is produced by boiling liquorice root and subsequently evaporating most of the water. The name 'liquorice'/'licorice' is derived (via the Old French licoresse), from the Greek γλυκύρριζα (glukurrhiza), meaning "sweet root",[5] from γλυκύς (glukus), "sweet"[6] + ῥίζα (rhiza), "root".[7][8] Liquorice extract is traded both in solid and syrup form. Its active principle is glycyrrhizin, a sweetener between 30 to 50 times as sweet as sucrose which also has pharmaceutical effects.
Liquorice flavour is found in a wide variety of liquorice candies. The most popular in the United Kingdom are liquorice allsorts. In continental Europe, however, far stronger, saltier candies are preferred. In most of these candies the taste is reinforced by aniseed oil, and the actual content of liquorice is very low.
In the Netherlands, where liquorice candy ("drop") is one of the most popular forms of sweet, only a few of the many forms that are sold contain aniseed, although mixing it with mint, menthol or with laurel is quite popular. Mixing it with ammonium chloride is also popular, and is known as Salmiak, but mixing it with table salt creates what is probably the most popular liquorice, known in the Netherlands as zoute drop. [9]
Pontefract in Yorkshire was the first place where liquorice mixed with sugar began to be used as a sweet in the same way it is in the modern day.[10] Pontefract Cakes were originally made there. In Yorkshire and Lancashire it is colloquially known as Spanish, supposedly because Spanish monks grew liquorice root at Rievaulx Abbey near Thirsk.[11]
Liquorice flavouring is also used in soft drinks, and in some herbal teas where it provides a sweet aftertaste. The flavour is common in medicines to disguise unpleasant flavours. Dutch youth often make their own "dropwater" (liquorice water) by putting a few pieces of laurel liquorice and a piece of liquorice root in a bottle with water and then shaking it to a frothy liquid.
Liquorice is popular in Italy (particularly in the South) and Spain in its natural form. The root of the plant is simply dug up, washed and chewed as a mouth freshener. Throughout Italy unsweetened liquorice is consumed in the form of small black pieces made only from 100% pure liquorice extract; the taste is bitter and intense. In Calabria a popular liqueur is made from pure liquorice extract. Liquorice is also very popular in Syria where it is sold as a drink. Dried liquorice root can be chewed as a sweet. Black liquorice contains approximately 100 calories per ounce (15 kJ/g).[12]
Chinese cuisine uses liquorice as a culinary spice for savoury foods. It is often employed to flavour broths and foods simmered in soy sauce.
Other herbs and spices of similar flavour include anise, star anise, tarragon, and fennel.
It is also the main ingredient of a very well known soft drink in Egypt, called عرقسوس ('erk-soos).
Sticks of liquorice typically have a diameter between two and ten millimetres. Although they resemble plain wooden sticks, they are soft enough to be chewed on. They used to be popular among Dutch, Danish and Swedish children. In Yorkshire in the early 1950s, wooden sticks of liquorice, around 8mm diameter, were readily available (and popular) in sweet shops. Also in Essex during late 50s. They were bought as 'sticks of liquorice', and they were chewed by young children. The wood was yellowish, and fibrous when chewed. Liquorice root can have either a salty or sweet taste. The thin sticks are usually quite salty and sometimes taste like salmiak (salty liquorice), whereas the thick sticks are usually quite sweet, with a salty undertone. Liquorice root is also widely available in Denmark. It is also sold by the drugstore and drysalter chain Matas and many greengrocers.
The compound glycyrrhizic acid, found in liquorice, is now routinely used throughout Japan for the treatment and control of chronic viral hepatitis, and there is a possible transaminase-lowering effect.[13] Hepatoprotective mechanisms have been demonstrated in mice.[14] Recent studies indicate that glycyrrhizic acid disrupts latent Kaposi sarcoma (as also demonstrated with other herpesvirus infections in the active stage), exhibiting a strong anti-viral effect.[15] The Chinese use licorice to treat Tuberculosis [16]
Liquorice affects the body's endocrine system as it contains isoflavones (phytoestrogens). It might lower the amount of serum testosterone slightly,[17] but whether it affects the amount of free testosterone is unclear. Consuming liquorice may prevent the development of hyperkalemia in persons on hemodialysis.[18] Large doses of glycyrrhizinic acid and glycyrrhetinic acid in liquorice extract can lead to hypokalemia and serious increases in blood pressure, a syndrome known as apparent mineralocorticoid excess. These side effects stem from the inhibition of the enzyme 11β-hydroxysteroid dehydrogenase (type 2) and subsequent increase in activity of cortisol on the kidney. 11β-hydroxysteroid dehydrogenase normally inactivates cortisol in the kidney; thus, liquorice's inhibition of this enzyme makes the concentration of cortisol appear to increase. Cortisol acts at the same receptor as the hormone aldosterone in the kidney and the effects mimic aldosterone excess, although aldosterone remains low or normal during liquorice overdose. To decrease the chances of these serious side effects, deglycyrrhizinated liquorice preparations are available. The disabling of similar enzymes in the gut by glycyrrhizinic acid and glycyrrhetinic acid also causes increased mucus and decreased acid secretion. As it inhibits Helicobacter pylori, is used as an aid for healing stomach and duodenal ulcers, and in moderate amounts may soothe an upset stomach. Liquorice can be used to treat ileitis, leaky gut syndrome, irritable bowel syndrome and Crohn's disease as it is antispasmodic in the bowels.[19]
Studies of the use of liquorice extract (usually at 7%) in the treatment of melasma have shown that glabridin inhibits tyrosinase activity of melanocytes. [20]
The compounded carbenoxolone is derived from liquorice. Some studies indicate that it inhibits 11β-Hydroxysteroid dehydrogenase type 1, an enzyme that is highly expressed in liver and fat tissues, where it plays a role in metabolism, and in the brain, where the same enzyme is involved in stress response that has been associated with age-related mental decline.[21][22]
In traditional Chinese medicine, liquorice(甘草) is commonly used in herbal formulae to "harmonize" the other ingredients in the formula and to carry the formula to the twelve "regular meridians"[23] and to relieve a spasmodic cough.
In herbalism it is used in the Hoxsey anti-cancer formula, and is a considered adaptogen which helps reregulate the hypothalamic-pituitary-adrenal axis. It can also be used for auto-immune conditions including lupus, scleroderma, rheumatoid arthritis and animal dander allergies.[19]
Glycyrrhizin from Glycyrrhiza root has been shown to modulate airway constriction, lung inflammation and infiltration of eosinophils in bronchial areas by stimulating CD4 and CD8 immune cell function.[24]
Liquorice may be useful in conventional and naturopathic medicine for both mouth ulcers[25] and peptic ulcers.[26]
Much liquorice production goes toward flavouring, sweetening and conditioning tobacco products.[27] Liquorice adds a mellow, sweet woody flavour and enhances the taste of tobacco. The burning liquorice also generates some toxins found in the smoke, and the glycyrrhizin expands the airways, which allows users to inhale more smoke.
Excessive consumption of liquorice or liquorice candy is known to be toxic to the liver[28] and cardiovascular system, and may produce hypertension[29] and edema.[30] In occasional cases blood pressure has increased with excessive consumption of liquorice tea, but such occasions are rare and reversible when the herb is withdrawn.[31] Most cases of hypertension from liquorice were caused by eating too much concentrated liquorice candy.[32] Doses as low as 50 grams (2 oz) of liquorice daily for two weeks can cause a significant rise in blood pressure.[33]
The European Commission 2008 report suggested that “people should not consume any more than 100mg of glycyrrhizic acid a day, for it can raise blood pressure or cause muscle weakness, chronic fatigue, headaches or swelling, and lower testosterone levels in men.” Haribo, manufacturer of Pontefract cakes, stated: “Haribo advises, as with any other food, liquorice products should be eaten in moderation.” A 56-year-old Yorkshire woman was hospitalized after liquorice overdose (200 grams or 7 ounces a day), which caused muscle failure. The hospital restored her potassium levels, by intravenous drip and tablets, allowing her to recover after 4 days.[34]
Comparative studies of pregnant women suggest that liquorice may also adversely affect both IQ and behaviour traits of offspring.[35]