(Caveats: Although the research is peer-reviewed https://pubmed.ncbi.nlm.nih.gov/37148757/ many experimental medical technologies do not work out. The hard part with insulin is not making it but making it in a form that takes effect quickly and stably, and it's those modern "stable" forms of Insulin that are expensive, because they're patented. The plant… also appears to be patented, by the University of Pennslyvania, although growing an illegal plant to treat diabetes is also very Solarpunk.)