Anti-Influenza Triterpene Saponins from the Bark of Burkea africana

J Nat Prod. 2018 Mar 23;81(3):515-523. doi: 10.1021/acs.jnatprod.7b00774. Epub 2018 Feb 2.

Abstract

In an in vitro cytopathic effect inhibition assay with the H3N2 influenza virus A/Hong Kong/68 (HK/68), the bark extract of Burkea africana was found to be a promising antiviral lead with an IC50 value of 5.5 μg/mL without noteworthy cytotoxicity in Madin Darby canine kidney cells. After several chromatographic steps, triterpene saponins of the lupane and oleanane types were identified as the bioactive principles. In total, eight new triterpene saponins (1-8) with four so far undescribed aglycone structures were isolated and characterized via HRESIMS, GC-MS, and 1D and 2D NMR spectroscopy. Their anti-influenza virus activity on HK/68 and the 2009 pandemic H1N1 strain A/Jena/8178/09 revealed the most potent effects by compounds 7 and 8, with IC50 values between 0.05 and 0.27 μM. This is the first time triterpene saponins have been reported as constituents of the investigated plant material.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antiviral Agents / chemistry*
  • Antiviral Agents / pharmacology*
  • Cytotoxins / chemistry
  • Cytotoxins / pharmacology
  • Dogs
  • Fabaceae / chemistry*
  • Humans
  • Influenza A Virus, H1N1 Subtype / drug effects
  • Influenza A Virus, H3N2 Subtype / drug effects
  • Inhibitory Concentration 50
  • Madin Darby Canine Kidney Cells
  • Oleanolic Acid / analogs & derivatives
  • Oleanolic Acid / chemistry
  • Oleanolic Acid / pharmacology
  • Orthomyxoviridae Infections / drug therapy
  • Saponins / chemistry*
  • Saponins / pharmacology*
  • Triterpenes / chemistry*
  • Triterpenes / pharmacology*

Substances

  • Antiviral Agents
  • Cytotoxins
  • Saponins
  • Triterpenes
  • oleanane
  • lupane
  • Oleanolic Acid