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Tuesday, 4 August 2015

2012 The antiviral activity of six South African plants traditionally used against infections in ethnoveterinary medicine

Veterinary Microbiology
Volume 155, Issues 2–4, 23 March 2012, Pages 198–206

The antiviral activity of six South African plants traditionally used against infections in ethnoveterinary medicine


doi:10.1016/j.vetmic.2011.09.015
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Abstract

Viral infections remain a major threat to humans and animals and there is a crucial need for new antiviral agents especially with the development of resistant viruses. The hexane, dichloromethane, acetone and methanol extracts of six plant species selected for their traditional use against infections were tested for in vitro antiviral activity against canine distemper virus (CDV), canine parainfluenza virus-2 (CPIV-2), feline herpesvirus-1 (FHV-1) and lumpy skin disease virus (LSDV). All extracts were tested for their cytotoxicity using a colorimetric tetrazolium-based (MTT) assay and were tested for antiviral efficacy at concentrations below CC50 values on the various cell types used in this study. The antiviral activity of extracts was tested using virucidal and attachment assays. In the virucidal assay, extracts were incubated with virus prior to infection. The most potent inhibition was observed with the acetone and methanol extracts of Podocarpus henkelii against CDV and LSDV, which inhibited replication of the viruses by >75% at 3 μg/ml with selectivity index (SI) values ranging between 12 and 45. Excellent activity was also found with the hexane extracts of Plumbago zeylanica and Carissa edulis against CDV, with the extracts reducing viral-induced CPE by 50% and 75% respectively. The hexane extract of C. edulis had moderate activity against FHV-1 with EC50 < 70 μg/ml and SI value <2. Only the acetone extract of P. henkelii moderately inhibited replication of LSD virus in the attachment assay, with low activity in other extracts. Of the four extracts with significant antiviral activity, two were prepared from P. henkelii. Therefore, future work will focus on isolating and characterizing the substance(s) responsible for bioactivity in extracts of this species.

Key words

  • South African medicinal plants;
  • Antiviral activity;
  • CDV;
  • LSDV;
  • CPIV-2;
  • FHV-1

Abbreviations

  • CDV, canine distemper virus;
  • LSDV, lumpy skin disease virus;
  • CPIV-2, canine parainfluenza virus-2;
  • FHV-1, feline herpesvirus-1

Corresponding author. Tel.: +27 12 529 8351; fax: +27 12 529 8525.
Copyright © 2011 Elsevier B.V. All rights reserved.
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