The antiviral and antimicrobial activities of licorice,a widely-used Chinese herb

Licorice is a common herb which has been used in traditional Chinese medicine for centuries. More than 20 triterpenoids and nearly 300 flavonoids have been isolated from licorice. Recent studies have shown that these metabolites possess many pharmacological activities, such as antiviral, antimicrobial, anti-inflammatory, antitumor and other activities. This paper provides a summary of the antiviral and antimicrobial activities of licorice. The active components and the possible mechanisms for these activities are summarized in detail. This review will be helpful for the further studies of licorice for its potential therapeutic effects as an antiviral or an antimicrobial agent.Abbreviations: CCEC, cerebral capillary vessel endothelial; CCL5, chemokine (C-C motif) ligand 5; CVA16, coxsackievirus A16; CVB3, coxsackievirus B3; CXCL10, chemokine, (C-X-C motif) ligand 10; DGC, dehydroglyasperin C; DHV, duck hepatitis virus; EV71, enterovirus 71; GA, 18β-glycyrrhetinic acid; GATS, glycyrrhizic acid trisodium salt; GL, glycyrrhizin; GLD, glabridin; HBV, hepatitis B virus; HCV, hepatitis C virus; HIV, human immunodeficiency virus; HMGB1, high-mobility-group box1; HRSV, human respiratory syncytial virus; HSV, herpes simplex virus; HSV1, herpes simplex virus type 1; IFN, interferon; IL-6, interleukin-6; LCA, licochalcone A; LCE, licochalcone E; ISL, isoliquiritigenin; LTG, liquiritigenin; MgIG, magnesium isoglycyrrhizinate; MRSA, methicillin-resistant Staphylococcus aureus; MSSA, methicillin-sensitive Staphylococcus aureus; PMN, polymorph nuclear; PrV, pseudorabies virus; TCM, traditional Chinese medicineKEY WORDS: Licorice, Antiviral, Antimicrobial, Glycyrrhizin, Glycyrrhetinic acid, Chalcone