In Vitro Inhibition of Severe Acute Respiratory Syndrome Coronavirus by Chloroquine

Biochem Biophys Res Commun. 2004 Oct 8;323(1):264-8. doi: 10.1016/j.bbrc.2004.08.085.

Abstract

We report on chloroquine, a 4-amino-quinoline, as an effective inhibitor of the replication of the severe acute respiratory syndrome coronavirus (SARS-CoV) in vitro. Chloroquine is a clinically approved drug effective against malaria. We tested chloroquine phosphate for its antiviral potential against SARS-CoV-induced cytopathicity in Vero E6 cell culture. Results indicate that the IC50 of chloroquine for antiviral activity (8.8 +/- 1.2 microM) was significantly lower than its cytostatic activity; CC50 (261.3 +/- 14.5 microM), yielding a selectivity index of 30. The IC50 of chloroquine for inhibition of SARS-CoV in vitro approximates the plasma concentrations of chloroquine reached during treatment of acute malaria. Addition of chloroquine to infected cultures could be delayed for up to 5h postinfection, without an important drop in antiviral activity. Chloroquine, an old antimalarial drug, may be considered for immediate use in the prevention and treatment of SARS-CoV infections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antimalarials / pharmacology
  • Antiviral Agents / pharmacology
  • Chlorocebus aethiops
  • Chloroquine / pharmacology*
  • Dose-Response Relationship, Drug
  • Humans
  • Inhibitory Concentration 50
  • RNA, Complementary / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • SARS Virus / metabolism*
  • Severe Acute Respiratory Syndrome / drug therapy*
  • Time Factors
  • Vero Cells
  • Virus Replication

Substances

  • Antimalarials
  • Antiviral Agents
  • RNA, Complementary
  • Chloroquine