Two flavonoids extracts from Glycyrrhizae radix inhibit in vitro hepatitis C virus replication.
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.
Sekine-Osajima
Yuko
Y
Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan.
Sakamoto
Naoya
N
Nakagawa
Mina
M
Itsui
Yasuhiro
Y
Tasaka
Megumi
M
Nishimura-Sakurai
Yuki
Y
Chen
Cheng-Hsin
CH
Suda
Goki
G
Mishima
Kako
K
Onuki
Yuko
Y
Yamamoto
Machi
M
Maekawa
Shinya
S
Enomoto
Nobuyuki
N
Kanai
Takanori
T
Tsuchiya
Kiichiro
K
Watanabe
Mamoru
M