from plants to antivirals
We are interested in using plant-derived natural product compounds to isolate, identify, and develop novel broad-spectrum antivirals. Extracts and natural-product compounds derived from plants have been historically used for various medicinal purposes, with various screens of plant extracts against a range of DNA and RNA viruses, identifying potential antiviral compounds.
Hydroxy-xanthones as promising antiviral agents: Synthesis and biological evaluation against human coronavirus OC43
In initial screens of various natural-product compounds, we identified mangiferin, a naturally occurring xanthone, to have anti-coronavirus activity. We found that mangiferin showed significant inhibition of infection by the common cold-causing human coronavirus OC43.

In collaboration with medicinal chemist Dr Tim Snape, we synthesised a panel of hydroxy-xanthones to investigate structure-activity relationships. The synthetic xanthones reduced OC43 infection by 2.0 - 2.8 log10 reduction (100 - 600x). Broadly, the addition of methyl functional groups increased antiviral activity compared to the xanthone core, however, there were no significant differences between the various hydroxy-xanthones. Interestingly, mangiferin showed the greatest antiviral efficacy (3.0 log10 or 1000x reduction), suggesting that the additional sugar moiety of mangiferin could be playing a role in its activity.
The published journal article is available here.
​We are continuing to investigate the mechanism of action of mangiferin and the synthetic xanthones, as well as develop methods to improve delivery of the xanthones to cells to enhance their bioavailability.