In the cover image this week, I am not sure how many readers will recognize the plant as a honeysuckle, but most will recognize the “spiked ball” as the virus responsible for Covid-19.

A colleague suggested that I write about honeysuckle because it is usedas a skin-soothing ingredient in cosmetic products. I did not expect to findmyself writing about #coronavirus.

Japanese Honeysuckle, botanical name Lonicera japonica, is native to E.Asia and an invasive species in other parts of the world. It is cultivated as an ornamental and also as an edible, medicinal plant.

Modern science shows that plants used in traditional medicine are loaded with interesting phytochemicals. One trend is “in silico” experimentation, using computer modelling to predict which molecules might bind to a target such as a pathogenic virus. In a study to find candidates that might act on theSARS-Cov1 virus, researchers identified #loniflavone, a biflavonoid from the leaves of L. japonica. Loniflavone is predicted to interfere with SARS-Cov2 in two ways. The first mechanism is by docking with the viral spike protein to block virus attachment and entry to host cells. The second mechanism is by binding to the RNA-methyltransferase enzyme translated by infected cells from thevirus RNA; this enzyme “caps” the viral RNA to protect it against the host antiviral response, allowing the virus to multiply and spread. The prediction is that loniflavone will bind these targets better than recognized antiviral drugs modelled in the same study.

But does it work? Well time will tell. The in silico study was publishedonly in 2021, and I have yet to find published, experimentally-verified proof of lonoflavone binding to SARS-Cov2 targets. Clinical studies are even further off and will likely come too late to help curb the Covid-19 pandemic.

But is loniflavone active IN THE PLANT? Probably YES, but not as defenseagainst SARS-Cov2.

Further reading

Wikipedia (2022)Lonicera japonica. https://en.wikipedia.org/w/index.php?title=Lonicera_japonica&oldid=1090100331

Kadioglu, O. et al. (2021). Identification of novelcompounds against three targets of SARS CoV-2 coronavirus by combined virtualscreening and supervised machine learning. Computers in biology andmedicine,133, 104359. https://doi.org/10.1016/j.compbiomed.2021.104359