K’an, Tynanthus guatemalensis Donn.Sm.: the Taxonomic and Archeological Mystery behind a Maya Antidiabetic Medicinal Plant (Invited)

Abstract

Consensus ethnobotanical field work was conducted with Q’eqchi’ Maya Healers of Mesoamercia to determine plants used to treat symptoms of diabetes. High consensus plants were tested in vitro for inhibition of advanced glycation end-product (AGE) formation. AGE formation is associated with long-term diabetic pathologies such as microvascular damage, neuropathy, nephropathy. Eight high consensus plant species (including one out group) were tested and all plant extracts showed AGE-inhibition. The most active was Tynanthus guatemalensis Donn.Sm. (used traditionally as an infusion and coffee substitute). Extracts of T. guatemalensis, gave an IC50 of 40.8 µg/mL and was comparable to the positive control, quercetin, a known AGE-inhibitor. The least active plant was Dioscorea hondurensis R.Knuth (the outgroup), with an IC50 >10 mg/mL. One unique character visible after a cross section of T. guatemalensis, is the xylem's cross shape organization. Upon cross-sectioning the woody liana, one can also smell T. guatemalensis' "Allspice" aroma. In a recent publication titled "Allspice as Template for the Classic Maya K’an Sign" the author illustrates how the Maya used the cross shaped xylem template as a decorative element on Late Classic (~750 CE) polychrome vessels and murals. However, the author incorrectly determined the decorative template as Pimenta dioica (L.) Merr. (common name: Allspice) based on a common aromatic plant quality – not a botanical voucher specimen. Here, we unlock the taxonomic and archeological mystery behind the Late Classic Maya K'an template with botanical vouchers of T. guatemalensis, and ascribe potent antidiabetic qualities to a contemporary and historically celebrated Maya medicinal plant.