Procyanidin B1 purified from Cinnamomi cortex suppresses hepatitis C virus replication.
BACKGROUND
A combination of pegylated interferon and ribavirin is the current standard therapy for hepatitis C virus (HCV) infection, but this combination provides relatively low efficacy, especially in some patients with HCV genotype 1 infection; therefore, the development of novel therapeutic agents is required for further improvement in the treatment of chronic HCV infection.


METHODS
HCV pseudotype and subgenomic replicon assays were used in this study. The interaction of compounds with HCV receptors was examined using flow cytometry. Intracellular RNA levels were determined by semi-quantitative reverse transcriptase PCR.


RESULTS
Procyanidin B1 (PB1), a dimer of (-)-epicatechin and (+)-catechin, purified from Cinnamomi cortex, inhibits infection by vesicular stomatitis virus and HCV pseudotype virus in Huh-7 cells, with 50% effective concentrations of 29 and 15 microM, respectively. No inhibitory effects were observed in each component of PB1. We found that PB1 does not interfere with viral entry or receptor expression, but inhibits HCV RNA synthesis in a dose-dependent manner.


CONCLUSIONS
These results indicate that PB1 suppresses HCV RNA synthesis, possibly as a HCV RNA polymerase inhibitor. Our results might contribute towards the development of more effective inhibitors for HCV infection from natural plants.
Li
Shenwei
S
Division of Emerging Infectious Diseases, Department of Internal Medicine, Tohoku University, Sendai, Japan.
Kodama
Eiichi N
EN
Inoue
Yuuki
Y
Tani
Hideki
H
Matsuura
Yoshiharu
Y
Zhang
Jing
J
Tanaka
Takashi
T
Hattori
Toshio
T
D000998:Antiviral Agents / Q000494:pharmacology* / Q000627:therapeutic use; D044946:Biflavonoids / Q000302:isolation & purification / Q000494:pharmacology* / Q000627:therapeutic use; D002392:Catechin / Q000302:isolation & purification / Q000494:pharmacology* / Q000627:therapeutic use; D045744:Cell Line, Tumor; D002935:Cinnamomum zeylanicum; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D016174:Hepacivirus / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D006526:Hepatitis C / Q000188:drug therapy; D019698:Hepatitis C, Chronic / Q000188:drug therapy; D006801:Humans; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000235:genetics / Q000494:pharmacology / Q000627:therapeutic use; D044945:Proanthocyanidins / Q000302:isolation & purification / Q000494:pharmacology* / Q000627:therapeutic use; D012367:RNA, Viral / Q000096:biosynthesis; D011994:Recombinant Proteins; D012093:Replicon / Q000187:drug effects; D012254:Ribavirin / Q000494:pharmacology / Q000627:therapeutic use; D053586:Virus Internalization / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects
D000998:Antiviral Agents; D044946:Biflavonoids; D004365:Drugs, Chinese Herbal; D000077190:Interferon alpha-2; D016898:Interferon-alpha; D044945:Proanthocyanidins; D012367:RNA, Viral; D011994:Recombinant Proteins; C532132:cinnamomi cortex; C479579:procyanidin B1; D012254:Ribavirin; D002392:Catechin