UC Davis

Cardiac glycosides (CGs), classified as cardenolides or bufadienolides, are toxins found in a variety of flora and fauna. CGs have historically been used to treat heart failure, but despite their place in medicine, they are still toxic to humans and animals. Currently, liquid chromatography paired with mass spectrometry (LC-MS) is used to screen for CGs. However, this requires using specific, costly, and often unavailable CG standards for reference. This study investigated the potential of identifying a cardenolide-containing (CC) plant using a plant’s overall cardenolide composition, represented by unique ions in the 300 to 400 m/z region in their mass spectra, rather than individual toxins. The chromatographic patterns of different plants at these select ions may provide unique “fingerprints” to serve as a means of identification. Not only would this provide an alternative to the standards, but it could also aid the diagnosis of cardenolide toxicosis in humans and animals, especially in cases where exposure history is unknown. To accomplish this, cardenolide standards in methanol were analyzed using UHPLC-HRMS and ions in the 300 to 400 m/z region exhibiting the “loss of 18 m/z” pattern were noted. These ions were grouped into “high”, “medium”, “low”, based on their masses, and “genin”. Next, 14 CC plants were individually homogenized in methanol and analyzed in replicate. The extracted ion chromatograms (EICs) at each ion of interest were observed for all plants. Blind tests were conducted to assess the ability to, using the EICs at the select ions, distinguish between CC and non-CC plants (Blind Test 1) and identify a CC plant (Blind Test 2). Blind Test 1 had a success probability of 1.0 across all ion groups, while Blind Test 2 had a success probability of 1.0 for the “high” and “medium” groups, and a success probability of 0.990 for the “low” and “genin” groups. Overall, this present study shows a promising start in using select ion chromatographic finger prints as a means of qualitatively identifying CC plants.