title: Two flavonoids extracts from Glycyrrhizae radix inhibit in vitro hepatitis C virus replication.
abstract: OBJECTIVE
  Traditional herbal medicines have been used for several thousand years in China and other Asian countries. In this study we screened herbal drugs and their purified compounds, using the Feo replicon system, to determine their effects on in vitro HCV replication.
  
  
  METHODS
  We screened herbal drugs and their purified extracts for the activities to suppress hepatitis C virus (HCV) replication using an HCV replicon system that expressed chimeric firefly luciferase reporter and neomycin phosphotransferase (Feo) genes. We tested extracts and 13 purified compounds from the following herbs: Glycyrrhizae radix; Rehmanniae radix; Paeoniae radix; Artemisiae capillari spica; and Rhei rhizoma.
  
  
  RESULTS
  The HCV replication was significantly and dose-dependently suppressed by two purified compounds, isoliquiritigenin and glycycoumarin, which were from Glycyrrhizae radix. Dose-effect analyses showed that 50% effective concentrations were 6.2 +/- 1.0 microg/mL and 15.5 +/- 0.8 microg/mL for isoliquiritigenin and glycycoumarin, respectively. The MTS assay did not show any effect on cell growth and viability at these effective concentrations, indicating that the effects of the two compounds were specific to HCV replication. These two compounds did not affect the HCV IRES-dependent translation nor did they show synergistic action with interferon-alpha.
  
  
  CONCLUSIONS
  Two purified herbal extracts, isoliquiritigenin and glycycoumarin, specifically suppressed in vitro HCV replication. Further elucidation of their mechanisms of action and evaluation of in vivo effects and safety might constitute a new anti-HCV therapeutics.
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Sekine-Osajima
authors.forename: Naoya
authors.initials: N
authors.lastname: Sakamoto
authors.forename: Mina
authors.initials: M
authors.lastname: Nakagawa
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Itsui
authors.forename: Megumi
authors.initials: M
authors.lastname: Tasaka
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nishimura-Sakurai
authors.forename: Cheng-Hsin
authors.initials: CH
authors.lastname: Chen
authors.forename: Goki
authors.initials: G
authors.lastname: Suda
authors.forename: Kako
authors.initials: K
authors.lastname: Mishima
authors.forename: Yuko
authors.initials: Y
authors.lastname: Onuki
authors.forename: Machi
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Shinya
authors.initials: S
authors.lastname: Maekawa
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Enomoto
authors.forename: Takanori
authors.initials: T
authors.lastname: Kanai
authors.forename: Kiichiro
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Mamoru
authors.initials: M
authors.lastname: Watanabe