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.