title: Glycyrrhizic acid as the antiviral component of Glycyrrhiza uralensis Fisch. against coxsackievirus A16 and enterovirus 71 of hand foot and mouth disease.
abstract: BACKGROUND
  The radices of Glycyrrhiza uralensis Fisch. and herbal preparations containing Glycyrrhiza spp. have been used for thousands of years as an herbal medicine for the treatment of viral induced cough, viral hepatitis, and viral skin diseases like ulcers in China. Glycyrrhizic acid (GA) is considered the principal component in Glycyrrhiza spp. with a wide spectrum of antiviral activity.
  
  
  OBJECTIVE
  The present study attempt to validate the medicinal use of Glycyrrhiza uralensis for hand, foot and mouth disease (HFMD) and further to verify whether GA is an active antiviral component in the water extract of Glycyrrhiza uralensis.
  
  
  METHODS
  Radices of Glycyrrhiza uralensis Fisch. were extracted with hot water. The chemical contents of the extract were profiled with HPLC analysis. The antiviral activity of the extract and the major components was evaluated against infection of enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) on Vero cells. The cytopathic effect caused by the infection was measured with MTT assay. Infectious virion production was determined using secondary infection assays and viral protein expression by immunoblotting analysis.
  
  
  RESULTS
  The extract at 1000 μg/ml suppressed EV71 replication by 1.0 log and CVA16 by 1.5 logs. The antiviral activity was associated with the content of GA in the extract since selective depletion of GA from the extract by acid precipitation resulted in loss of antiviral activity. In contrast, the acid precipitant retained antiviral activity. The precipitant at a concentration of 200 μg/ml inhibited EV71 and CVA16 replication by 1.7 and 2.2 logs, respectively. Furthermore, GA dose-dependently blocked viral replication of EV71 and CVA16. At 3 mM, GA reduced infectious CVA16 and EV71 production by 3.5 and 2.2 logs, respectively. At 5mM, CVA16 production was reduced by 6.0 logs and EV71 by 4.0 logs. Both EV71 and CVA16 are members of Enterovirus genus, time-of-drug addition studies however showed that GA directly inactivated CVA16, while GA anti-EV71 effect was associated with an event(s) post virus cell entry.
  
  
  CONCLUSIONS
  This study validated the medicinal usefulness of radices Glycyrrhiza uralensis against the etiological agents of HFMD. In addition to the identification of GA as the antiviral component of Glycyrrhiza uralensis against EV71 and CVA16 infection, this study also reveals that GA inhibits EV71 and CVA16 with distinct mechanisms.
authors: Jiangsu Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing 210093, China.
authors: Jingjing
authors: J
authors: Wang
authors: Xiaoqing
authors: X
authors: Chen
authors: Wei
authors: W
authors: Wang
authors: Yating
authors: Y
authors: Zhang
authors: Ziying
authors: Z
authors: Yang
authors: Yu
authors: Y
authors: Jin
authors: Hui Ming
authors: HM
authors: Ge
authors: Erguang
authors: E
authors: Li
authors: Guang
authors: G
authors: Yang
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D015153:Blotting, Western; D011232:Chemical Precipitation; D002522:Chlorocebus aethiops; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D004770:Enterovirus / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity; D029821:Enterovirus A, Human / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity; D029882:Glycyrrhiza uralensis / Q000737:chemistry; D019695:Glycyrrhizic Acid / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D006232:Hand, Foot and Mouth Disease / Q000188:drug therapy* / Q000821:virology; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D018517:Plant Roots; D010946:Plants, Medicinal; D012997:Solvents / Q000737:chemistry; D013997:Time Factors; D014709:Vero Cells; D014764:Viral Proteins / Q000378:metabolism; D053586:Virus Internalization / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects; D014867:Water / Q000737:chemistry
chemical_list: D000998:Antiviral Agents; D010936:Plant Extracts; D012997:Solvents; D014764:Viral Proteins; D014867:Water; D019695:Glycyrrhizic Acid