Antiviral activity of the Indian medicinal plant extract Swertia chirata against herpes simplex viruses: a study by in-vitro and molecular approach

Indian J Med Microbiol. 2008 Oct-Dec;26(4):322-6.


Purpose: The antiviral activity of Indian Medicinal plant extract Swertia chirata was tested against Herpes simplex virus (HSV) type-1, using multiple approaches both at cellular and molecular level.

Methods: Cytotoxicity, plaque reduction, virus infectivity, antigen expression and polymerase chain reaction (PCR) assays were conducted to test the antiviral activity of the plant extract.

Results: Swertia plant crude extract (1 gm/mL) at 1:64 dilution inhibited HSV-1, plaque formation at more than 70% level. HSV antigen expression and time kinetics experiments conducted by indirect immunofluorescence (IFA) test, revealed a characteristic pattern of small foci of single fluorescent cells in Swertia extract treated HSV-1 infected cells at 4 hours post infection dose, suggested drug inhibited viral dissemination. Infected cell cultures treated with Swertia extract at various time intervals, tested by PCR, failed to show amplification at 12, 24-72 hours. HSV-1 infected cells treated with Acyclovir (antiviral drug) did not show any amplification by PCR.

Conclusions: In this preliminary study, the Indian medicinal plant extract, Swertia chirata showed antiviral properties against Herpes simplex virus type-1.

MeSH terms

  • Acyclovir / pharmacology
  • Animals
  • Antigens, Viral / metabolism
  • Antiviral Agents / pharmacology*
  • Chlorocebus aethiops
  • Fluorescent Antibody Technique, Indirect
  • Herpesvirus 1, Human / drug effects*
  • Herpesvirus 1, Human / pathogenicity
  • Herpesvirus 1, Human / physiology
  • Humans
  • Plant Extracts / pharmacology*
  • Plant Extracts / toxicity
  • Plants, Medicinal / chemistry*
  • Plants, Medicinal / toxicity
  • Polymerase Chain Reaction
  • Swertia / chemistry*
  • Swertia / toxicity
  • Vero Cells
  • Viral Plaque Assay


  • Antigens, Viral
  • Antiviral Agents
  • Plant Extracts
  • Acyclovir