Welcome to WONDERFUL World of LICORICE!!!

Hey everybody, welcome to my blog! Hope you enjoy learning about the health benefits and history of the licorice root.

The Ancient Beginnings of the Licorice Root

Throughout history two main varieties of the licorice root have been used by cultures all around the world. These include Glycyrrhiza glabra and Glycyrrhiza uralensis (Davis et al, 1991). Glycyrrhiza glabra is the licorice commonly used by the Western world today and is found in Greece, Turkey, Russia, Spain, Iraq and Northern China (Davis et al, 1991).  The usage of this herb dates back to the time of Ancient Egypt where it was found in the 3000 year old tomb of King Tut (Davis et al, 1991). The Ancient Egyptians placed licorice next to the pharaoh as ritual believing that once he reaches the afterlife he may use this root to create the sweet drink mai sus, which is still consumed today (Davis et al, 1991). The Ancient Greeks in the first millennium B.C. were also avid fans of licorice as they believed that it ingesting can treat asthma and when combined with honey it could be used as a topical medicine to heal wounds (Davis et al, 1991). It was also believed at the time that when used as lozenge it could clear the throat and delay feelings of hunger and thirst (Davis et al, 1991).





King Tut and Alexander the Great, both licorice lovers-http://www.americanlicorice.com/aboutUs/historyOfLicorice.aspx

  
Glycyrrhiza uralensis is indigenious to Northern China, Mongolia, and Siberia (Davis et al, 1991) and its medicinal purposes were believed to be documented several thousand years ago by Shen Nong , the father of traditional Chinese medicine (Steven Foster Group INC., 2008). It has been historically used as a tonic for many disorders such as an antidote for mushroom poisoning, as a painkiller to sooth sore throats and coughs,  and to cure toxic abscesses and acute abdominal pains (Davis et al, 1991).  Also it can be added to food to treat acne, heat stroke and psychological disorders such as manic depression, hysteria and violent temper (Davis et al, 1991).

What's Inside the Root?

Both Glycyrrhiza glabra and Glycyrrhiza uralensis consist of many active components such triterpenes, flavonoids, alkaloids, coumarin derivatives, isoflavanoids and chalcones, all of which interact to provide the medicinal effects of licorice (Chan et al., 2010). But the main active component which most of the current research on licorice has been focused on is the triterpene Glycyrrrhizic acid, also known as glycyrrhizin (Chan et al., 2010).

Structure of glycyrrhizin- http://www.sweetenerbook.com/images/glycyrrhizin.gif

As licorice root is commonly used in traditional Chinese medicine as a guide drug to enhance the effect of other supplements (Kitagawa, 2002), it requires several processing procedures in order to achieve its medicinal potential and to improve its pharmaceutical functions (Kitagawa, 2002). These include physical processes such as peeling of the outer layers, water processing which involves soaking and washing the root, fire processes such as burning and broiling, and finally a combination of these processes which include steaming the root (Kitagawa, 2002). Once this is complete, the root is air dried  (Kitagawa, 2002) and usually ingested as an extract which is created by boiling the root and consuming the resulting water (Isbrucker et al, 2006).

The 21st Century Usage of Licorice:

Today Glycyrrhiza glabra’s uses are primarily centered in the tobacco and confectionary industries in Western countries (Davis et al, 1991). In the tobacco industry, licorice is used as a conditioning and flavouring agent and has been used for this process for over 100 years (Davis et al, 1991).  Many candies are processed from licorice through a water extract procedure followed by vacuum concentration which forms a ‘block juice’ that the licorice candies are made from (Davis et al, 1991). Once this juice combined with sugar, corn syrup and flour it can molded into any shape and marketed as licorice candy (Davis et al, 1991).  This process does not occur in as much abundance as in the past as substitute flavouring agents have been introduced instead (Davis et al, 1991), but several licorice candies still follow this process such as Twizzlers Black licorice candy (Hershey’s, 2010).  For medicinal purposes, licorice has been used as a treatment for peptic ulcers in a chewable form that does not contain glycyrrhizin (Sena, ,2011). It has also been used as a messenger drug to improve to absorption when used in combination with other drugs due to its ability to inhibit intestinal p-glycoprotein and the multidrug resistance transporter protein ABCB1 (Chan et al, 2010).  Recent clinical data has shown an increased focus on the many medicinal benefits of licorice and have based many of their studies on Glycyrrhiza uralensis. Along with reducing prostate cancer metastatic abilities (Park, 2010), Glycyrrhiza uralensis extract has been shown to prevent amyloid-β-induced neurotixicity and reduce arthritis induced inflammation in vitro and in vivo: 

Effect of Licorice (Glycyrrhiza uralensis Fisch) on Amyloid-β-induced Neurotoxicity in PC12 Cells-

A study by Ahn et al (2010) showed a protective effect from amyloid-β (Aβ) peptide plaques, a characteristic in Alzheimer’s disease, in rat medulla PC12 cells when exposed to a licorice water extract.  The neurotoxicity of Aβ is mediated by an increase in reactive oxidative species and the researchers found that when the water extract was added in a dose dependent matter, an increase in cell viability was seen in the MTT assay (Ahn et al, 2010). Lipid peroxidation was also reported to be reduced with water extract exposure (Ahn et al, 2010). Finally through western blot analysis, a reduction in expression of proapoptotic proteins BAX, PARP, and caspase-3 was seen while and increase in antiapoptotic protein BCL-2 expression was seen (Ahn et al, 2010). Although only in vitro experiments were shown, this report is in agreement with previous reports stating that licorice extract contains antioxidant and antiapoptotic properties (Ahn et al, 2010). 

Ahn et al, 2010

Anti-Inflammatory Effects of Licorice and Roasted Licorice Extracts on TPA-Induced Acute Inflammation and Collage-Induced Arthritis in Mice-

A 2010 study by Kim et al showed both in vivo and ex vivo anti-inflammatory effects of licorice and roasted licorice extracts when used in the murine collagen induced arthritis (CIA) model of human rheumatoid arthritis. The CIA model is performed by injecting collagen in the joints of the mice and allowing the development of arthritis and swelling to occur (Kim et al, 2010). Oral ingestion of both extracts led to reductions in clinical arthritis score, paw swelling, oxidative damage, proinflammatory cytokines and matrix metalloproteinases expression compared to CIA model only controls (Kim et al, 2010). Similar inflammatory reductions were also seen ex vivo as well using murine CIA model tissue (Kim et al, 2010). The anti-arthritic effect for both roasted licorice and licorice extracts were similar and provide a better understanding on the effects of different processing techniques for the root (Kim et al, 2010).

Kim et al., 2010

Trials such as the ones above reinforce the past claims by ancient populations that many health benefits can be achieved through use of the licorice root.  As research is growing in this field, the potential for new therapeutic treatments using licorice may be realized soon in the future.

Things You Should Be Concerned About:

Several side effects have been reported with excessive usage of licorice extracts. These include hypertension, hypokalemia, metabolic alkalosis and sodium and water retention, which are symptoms that appear in patients who are suffering from mineralocorticoid excess (Sena,  2011). The work of Farese et al was able to show the exact mechanism of such symptoms as he concluded that the major component, glycyrrhizin, was responsible for inhibiting the enzyme 11β-HSD2, which is involved in converting cortisol into cortisone (Sena,  2011). When an excess of glycyrrhizin from licorice was ingested, a reduction in cortisone levels occurred resulting in an increase in cortisol binding with mineralocorticoid receptors.



Inhibitory action of Glycyrrhizic Acid- Sena, 2011


This caused the production of symptoms for a condition now known as pseudohyperaldosteronism (Sena,  2011). These adverse effects are only lethal when licorice intake is excessive (such as 280 mg/day of glycyrrhizin in one autopsy report) and for certain individuals who are sensitive to its effects (Sena,  2011). These populations include pediatric patients, patients with estrogen-dependent cancers, pregnant and breast feeding women, and people with underlying heart arrhythmia and hypertension (Sena, 2011). Therefore a daily intake of 0.2mg/kg is recommended (Isbrucker et al, 2006). Licorice has also been demonstrated to interact with many pharmaceutical drugs. The drug prednisolone, a drug used for Addison’s disease, has been shown to have reduced clearance when licorice is present, thus increasing the bioavailability of prednisolone in the body and potentiating its effect (Chen, 2010). Licorice has also been shown to potentiate the vasoconstriction effects of hydrocortisone when used in combination (Chan et al, 2010). Overall, licorice has been reported to interact with over 100 pharmaceutical drugs such as laxatives, corticosteroids, diuretics and anti-hypertensives but none have shown to have deleterious effects (Chan et al, 2010).

References:

1.       Ahn JI et al. (2010). Effect of Licorice (Glycyrrhiza uralensis Fisch) on Amyloid-β-induced Neurotoxicity in PC12 Cells. Food Sci Biotechnol 19(5): 1391-1395.

2.       Chan E et al. (2010). Interactions between traditional Chinese Medicines and Western Therapeutics. Current Opinion in Drug Discovery & Development 13(1): 50-63.

3.       Chen M et al. (1990).  Effect of Glycyrrhizin on the Pharmacokinetics of Prednisolone Following Low Dosage of Prednisolone Hemisuccinate. Endocrinology Japan 37(3): 331-341.

4.       Sena, S. (2011). Licorice and Laboratory Tests. In Dasgupta, A et al., Herbal Supplements: Efficacy, Toxicity, Interactions with Western Drugs, and Effects on Clinical Laboratory Tests. Hoboken, NJ: John Wiley and Sons INC.

5.       Davis E et al. (1991). Medicinal Uses of Licorice Through the Millennia: The Good and Plenty of it. Molecular and Cellular Endocrinology 78: 1-6.

6.       Hershey’s. (2010). Licorice. Retrieved on November 27^th, 2010 from http://www.thehersheycompany.com/nutrition-and-wellness/confections-101/licorice-and-glycyrrhizic-acid.aspx

7.       Isbrucker, R et al. (2006). Risk and Safety Assessment on the Consumption of Licorice Root (Glycyrrhiza sp.), its Extract, and Powder as a Food Ingredient, with Emphasis on the Pharmacology and Toxicology of Glycyrrhizin. Regulatory Toxicology and Pharmacology 46: 167-192.

8.       Kim K et al. (2010). Anti-Inflammatory Effects of Licorice and Roasted Licorice Extracts on TPA-Induced Acute Inflammation and Collage-Induced Arthritis in Mice. Journal of biomedicine and Biotechnology: 1-8.

9.       Kitagawa, I. (2002). Licorice Root. A Natural Sweetener and an Important Ingredient in Chinese Medicine. Pure Appl Chem 74(7): 1189-1198.

10.   Park, SY et al. (2010). Hexane-Ethanol Extract of Glycyrrhiza Uralensis Containing Licoricidin Inhibts the Metastatic Capacity of DU145 Human Prostate Cancer Cells. British Journal of Nutrition. May 21: 1-11.

11.   Steven Foster Group INC. (2008). Licorice-Glycyrrhiza. Retrieved on November 27^th,2010 from http://www.stevenfoster.com/education/monograph/licorice.html

Herbal Medicine & Home Remedies : Uses for Licorice Root