When Roni Kramer suggested that I write about #defensins, I knew that she was interested because of their importance in dermatology. Defensins had not yet been invented when I was an undergraduate, and my first response was “of what possible relevance are they in plants?

It did not take me longto discover that defensins appear in vertebrates, invertebrates, fungi and ….yes, plants. The molecule illustration within the cover picture is a model oftomato defensin TPP3, constructed using published atomic coordinates [1].

Defensins are small, cystine-rich proteins with antimicrobial and many other properties, to the extent that they have beenproclaimed the “Swiss army knives” of host defense [2].They tend to act by disrupting membranes, perhaps killing an attackingpathogen, or maybe otherwise having a signal role to induce host responses.

As regular readers of this series may now realise, we Green Mountain Biotech are focused on extracting plant bioactive for use in dermatological products. Defensins are not among them! However some of our botanical extracts tend to induce expression of defensins in human skin cells, notably extracts of Ailanthus and Sanguisorba [3]. This helps the skin defend itself against infection and also helps control other innate mechanisms that contribute to skin health.

[1]       PDB Entry - 4UJ0,Crystal structure of the tomato defensin TPP3 http://dx.doi.org/10.2210/pdb4uj0/pdb
Primary publication http://dx.doi.org/10.1128/MCB.00282-15

[2]      Xu, D. and Lu, W.2020. Defensins: A Double-Edged Sword in Host Immunity. Frontiers in Immunology. 11, (May 2020), 764. https://doi.org/10.3389/FIMMU.2020.00764/BIBTEX

[3]      WO2012090205 Plant extracts for the treatment and prevention of infections: https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2012090205

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