Title:Ethnomedicinal Plant Stephania hernandifolia and its Active Fraction 2-
Chloroethyl Linoleate Inhibits HSV-2 Infection by Blocking Viral Immediate
Early and Early Transcription
Volume: 17
Issue: 4
Author(s): Joy Mondal, Chiranjit Patra, Ananya Das Mahapatra, Keshab Chandra Mandal and Debprasad Chattopadhyay*
Affiliation:
- ICMR-National Institute of Cholera and Enteric Disease (NICED) Virus Unit, ID & BG Hospital, GB-4, First Floor,
57 Dr. Suresh C. Banerjee Road, Beliaghata, Kolkata 700010, India
- ICMR-National Institute of Traditional Medicine, Nehru Nagar, Belagavi 590010, India
Keywords:
Ethnomedicine, Stephania hernandifolia, herpes simplex virus type 2, antiviral activity, GC-MS, mass spectra, NMR, FTIR.
Abstract:
Aims: The aim of this study is validation of antiviral activity of Stephania hernandifolia
against HSV-2.
Background: Ethnomedicinal plant Stephania hernandifolia, traditionally used for the management of
skin, digestive and nerve ailments demonstrated significant anti-HSV-1 activity; similar to Stephania
cepharantha having neuroinflammatory and anti-HSV activities.
Objectives: Thus, the present study aimed to validate the potential of the most active fraction-2 (F-2)
of S. hernandifolia against HSV-2 in vitro, along with the underlying mode or mechanism of action.
Methods: The standardized F-2 was characterized by GC-MS, 1H-NMR, Mass and FTIR spectroscopy.
Cytotoxicity (CC50) and antiviral activity (EC50) were evaluated by MTT and Plaque reduction assay.
To determine the mode of action, we have used time-of-addition, virus inactivation, and entry (attachment
and penetration) assays, followed by semiquantitative PCR. Furthermore, the protein expression
levels of immediate early (IE) and early (E) gene products of drug-treated virions were measured
by Western blot.
Results: The results showed that HSV-2G and ICMR/VU-2012/20, the clinical isolate of HSV-2, were
inhibited by F-2 at EC50 of 20.0 and 20.43 μg/ml respectively, with Selectivity Index (SI) of 12. Timeof-
addition assay showed that F-2 significantly inhibited HSV-2 infection in Vero cells at 4-8 h posttreatment.
The infectivity of the virion was lost within 1h of exposure to F-2 (EC50 and EC99). Furthermore,
semi-Q-PCR and Western blot studies demonstrated significant downregulation of IE and E
gene products. The characterization revealed that 2-chloroethyl linoleate is the lead compound in the
F-2 fraction.
Conclusion: Thus, our results showed that the bioactive fraction F-2 inhibits both IE and E transcription
of HSV-2.