Coeliacs, snakebites and the perils of apricots…

Nigel Chaffey continues his exploration of the unexpected health benefits of some foods.

Continuing with the 2017 Kew’s State of the World’s Plants report which documents medicinal uses for a mere 7.6 % (28,187 out of an estimated 369,400 species of flowering plants (p. 9), here’s some more news of potentially life-changing, plant-derived pharmaceutical possibilities…

Nepenthes × ventrata
Nepenthes × ventrata. Photo: François de Dijon / Wikipedia

Help with a human digestion problem – coeliac diseasecomes from an unexpected angle, a botanic with its own digestion-related physiology, the pitcher plant Nepenthes. The symptoms of coeliac disease result from the body’s inability to fully digest gluten protein in certain cereal products. Analysis of the digestive protein complement of Nepenthes × ventrata by Linda Lee et al. identified an enzyme – neprosin, a prolyl endoprotease – that could digest gluten. A demonstration that this discovery could bring some relief to human coeliac sufferers comes from work by Martial Rey et al. with mice. Which raises the question of how many other interesting enzymes, that work in low pH environments such as the human stomach, carnivorous plants may contain. Or organisms of otherwise interesting biochemistry such as fungi (e.g. these papers). But, rather than search for natural ‘coelical cures’, why not intelligently design them? With the aid of the CRISPR/Cas9 gene-editing technology, Susana Sánchez-León et al. have produced low-gluten, non-transgenic wheat plants – ‘bread wheat’ and durum wheat’. Although what they created is low in gluten rather than gluten-free it does give a glimpse into the brave new world of future possibilities that this new CRISPR technology might offer in the quest for ‘designer foods’ to cope with a variety of digestively-compromised people.

Chrysopelea ornata or "the golden tree snake.
Chrysopelea ornata or “the golden tree snake”. Photo: Conrad Baetsle

Finally, in this ‘plants are good for people’ catalogue, there is a consideration of ‘snake bite plants’. A review of plants used indigenously to treat snake bites in Central America by Peter Giovannini and Melanie-Jayne Howes identified 208 flowering plant species exploited in this capacity. However, although traditionally used in this way, the duo concluded that ‘there is a lack of clinical research to evaluate their efficacy and safety.’ This underlines the need to undertake more research into the medicinal/pharmaceutical potential of the planet’s plant profusion. And, by way of a cautionary tale about humans using plants as medicines in an unorganised way…

Apricot painting
The ‘Turkey’ apricot, a hand-coloured engraving after a drawing by Augusta Innes Withers (1792-1869), from the first volume of John Lindley’s Pomological Magazine (1827-1828). With thanks to BernardM / Wikipedia

…we highlight the case of an otherwise healthy 67-year-old man who gave himself cyanide poisoning by self-prescribing a supposedly cancer-preventing concoction based on kernels of apricots [Prunus armeniaca presumably, but not specified by scientific name in the journal article…]. Plants, good for what ails you – if used wisely (!). Just so.

Reference List

Lee, L., Zhang, Y., Ozar, B., Sensen, C. W., & Schriemer, D. C. (2016). Carnivorous Nutrition in Pitcher Plants (Nepenthes spp.) via an Unusual Complement of Endogenous Enzymes. Journal of Proteome Research, 15(9), 3108–3117. https://doi.org/10.1021/acs.jproteome.6b00224

Rey, M., Yang, M., Lee, L., Zhang, Y., Sheff, J. G., Sensen, C. W., … Schriemer, D. C. (2016). Addressing proteolytic efficiency in enzymatic degradation therapy for celiac disease. Scientific Reports, 6(1). https://doi.org/10.1038/srep30980

Rottloff, S., Miguel, S., Biteau, F., Nisse, E., Hammann, P., Kuhn, L., … Bourgaud, F. (2016). Proteome analysis of digestive fluids in Nepenthes pitchers. Annals of Botany, 117(3), 479–495. https://doi.org/10.1093/aob/mcw001

Stepniak, D., Spaenij-Dekking, L., Mitea, C., Moester, M., de Ru, A., Baak-Pablo, R., … Koning, F. (2006). Highly efficient gluten degradation with a newly identified prolyl endoprotease: implications for celiac disease. American Journal of Physiology-Gastrointestinal and Liver Physiology, 291(4), G621–G629. https://doi.org/10.1152/ajpgi.00034.2006

Mitea, C., Havenaar, R., Drijfhout, J. W., Edens, L., Dekking, L., & Koning, F. (2007). Efficient degradation of gluten by a prolyl endoprotease in a gastrointestinal model: implications for coeliac disease. Gut, 57(1), 25–32. https://doi.org/10.1136/gut.2006.111609

Sánchez-León, S., Gil-Humanes, J., Ozuna, C. V., Giménez, M. J., Sousa, C., Voytas, D. F., & Barro, F. (2017). Low-gluten, nontransgenic wheat engineered with CRISPR/Cas9. Plant Biotechnology Journal. https://doi.org/10.1111/pbi.12837

Giovannini, P., & Howes, M.-J. R. (2017). Medicinal plants used to treat snakebite in Central America: Review and assessment of scientific evidence. Journal of Ethnopharmacology, 199, 240–256. https://doi.org/10.1016/j.jep.2017.02.011

Konstantatos, A., Shiv Kumar, M., Burrell, A., & Smith, J. (2017). An unusual presentation of chronic cyanide toxicity from self-prescribed apricot kernel extract. BMJ Case Reports, bcr–2017–220814. https://doi.org/10.1136/bcr-2017-220814