Authentication of tejocote (Crataegus mexicana) dietary supplements based on DNA barcoding and chemical profiling.

Tejocote (Crataegus mexicana, Mexican hawthorn), known as a weight-loss supplement, has been marketed online and is easily available for overseas direct purchase. Alipotec (brand name) is known as one of the most popular products containing tejocote in Mexico and other countries. However, adverse effects have been reported by users of these supplements. Therefore it is necessary to find the reason for the side effect. Dietary supplement samples labelled as containing tejocote were analysed using mass spectrometry and DNA barcoding analysis. Our results demonstrate that Alipotec samples contained ingredients from different species, yellow oleander instead of tejocote. The rpoB barcode region was able to differentiate between tejocote and yellow oleander species. Moreover, it was also observed that three compounds, including thevetin B, neriifolin, and digitoxigenin, clearly distinguish between tejocote and yellow oleander samples. This is the first and preliminary investigation to use an integrated approach of both chemical and genomic profiling for the authentication of dietary supplement containing tejocote.

Changes in cardiac glycoside activity produced by aminosugar addition.

In anesthetized dogs, structure activity relationships among three cardiotonic compounds were determined by comparing the cardiovascular effects of digotoxigenin (the genin) to digitoxigenin-galactose (a genin-neutral sugar combination) and to digitoxigenin-aminogalactose (ASI-222, a genin-aminosugar combination) using either bolus i.v. injections or constant i.v. infusions. We recorded the effects of these drugs upon cardiac rate, mean blood pressure, left ventricular dP/dt, cardiac index, systolic time intervals, tension-time index, therapeutic index, ventricular excitability and the ventricular refractory period. The addition of an aminosugar group to digitoxigenin or an amine group to galactose-digitoxigenin results in an agent with greater ability to reduce heart rate and to increase cardiac contractility and cardiac index without affecting the tension-time index. Moreover, the addition of an amino group significantly increased the therapeutic index and ventricular refractory period but reduced the toxic index (lethal dose/toxic dose) when compared to the neutral-sugar cardenolide and genin. Our data indicate that such a substitution confers greater potency, prolongs the duration of activity and results in a compound with a greater therapeutic index.