Psammaplin A inhibits hepatitis C virus NS3 helicase

Kazi Abdus Salam, Atsushi Furuta, Naohiro Noda, Satoshi Tsuneda, Yuji Sekiguchi, Atsuya Yamashita, Kohji Moriishi, Masamichi Nakakoshi, Masayoshi Tsubuki, Hidenori Tani, Junichi Tanaka*, Nobuyoshi Akimitsu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


Hepatitis C virus (HCV) is the causative agent of hepatitis C, a chronic infectious disease that can lead to development of hepatocellular carcinoma. The NS3 nucleoside triphosphatase (NTPase)/helicase has an essential role in HCV replication, and is therefore an attractive target for direct-acting antiviral strategies. In this study, we employed high-throughput screening using a photo-induced electron transfer (PET) system to identify an inhibitor of NS3 helicase from marine organism extracts. We successfully identified psammaplin A as a novel NS3 inhibitor. The dose-response relationship clearly demonstrates the inhibition of NS3 RNA helicase and ATPase activities by psammaplin A, with IC50 values of 17 and 32 μM, respectively. Psammaplin A has no influence on the apparent K m value (0.4 mM) of NS3 ATPase activity, and acts as a non-competitive inhibitor. Additionally, it inhibits the binding of NS3 to single-stranded RNA in a dose-dependent manner. Furthermore, psammaplin A shows an inhibitory effect on viral replication, with EC 50 values of 6.1 and 6.3 μM in subgenomic replicon cells derived from genotypes 1b and 2a, respectively. We postulate that psammaplin A is a potential anti-viral agent through the inhibition of ATPase, RNA binding and helicase activities of NS3.

Original languageEnglish
Pages (from-to)765-772
Number of pages8
JournalJournal of Natural Medicines
Issue number4
Publication statusPublished - 2013 Oct


  • Hepatitis C virus
  • NS3 RNA helicase
  • Photo-induced electron transfer
  • Psammaplin A

ASJC Scopus subject areas

  • Molecular Medicine


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