Analysis of Toxic Norditerpenoid Alkaloids in Delphinium Species by Electrospray, Atmospheric Pressure Chemical Ionization, and Sequential Tandem Mass Spectrometry

Abstract

A rapid electrospray mass spectrometry method was developed for screening larkspur (Delphinium spp.) plant material for toxic norditerpenoid alkaloids. The method was calibrated using two standard alkaloids, methyllycaconitine (1) and deltaline (2), with a recovery of 92% from spiked samples and relative standard deviations of 6.0% and 8.1% for the two alkaloids, respectively. Thirty-three samples of plains larkspur, Delphinium geyeri, were analyzed. Methyllycaconitine (1) concentration was 0.27% +/- 0.08% during a 1-month period in 1997 establishing the relative risk of poisoning from the plant to be low. The method was also applied to the trace analysis (<1 ppm) of 1 in serum samples from sheep dosed different levels of the alkaloid. Electrospray ionization combined with sequential tandem mass spectrometry and HPLC coupled to atmospheric pressure chemical ionization (APCI) mass spectrometry were used to detect and tentatively identify three new norditerpenoid alkaloids from Delphinium nuttallianum [bearline (6), 14-acetylbearline (7), 16-deacetylgeyerline (8)]. The tentative structure of the new alkaloids was predicted from the tandem mass spectra fragmentation patterns and assigning the substitution pattern for methoxy and acetyl groups at the C-14 and C-16 carbons.

Development of a PCR-Based Method for Detection of Delphinium Species in Poisoned Cattle

“…Prepared mixtures of plant material were analyzed for larkspur alkaloids by LC−MS. 20 An aliquot of plant material (100 mg) was extracted with 4.0 mL of methanol for 2 h by mechanical rotation in a sealed (screw cap) test tube. The sample was filtered, and a 0.500 mL aliquot of the extract was diluted with 0.500 mL of 20 mM ammonium acetate in a 1.5 mL autosample vial.…”

Adverse Effects of Larkspur (Delphinium spp.) on Cattle

“…HPLC methods developed have used both normal phase [13] and reverse phase [39,40] type separations. When combined with atmospheric ionization and mass spectrometry (i.e., HPLC-esi(+)MS) the methods can become extremely sensitive and selective [20,[41][42][43][44]. Even in the absence of chromatography, a simple flow injection mass spectrometry method can be a valuable tool in assessing the alkaloid composition of larkspurs [42].…”

“…When combined with atmospheric ionization and mass spectrometry (i.e., HPLC-esi(+)MS) the methods can become extremely sensitive and selective [20,[41][42][43][44]. Even in the absence of chromatography, a simple flow injection mass spectrometry method can be a valuable tool in assessing the alkaloid composition of larkspurs [42]. Such flow injection methods have been valuable in chemo-typing the various larkspurs based on alkaloid profiles, geographical location and species identifications [17][18][19].…”

“…With development of fully hyphenated methods, such as LC-MS/MS, the sensitivity and selectivity have become sufficient for detection of very low concentration of alkaloids (i.e., ng/mL) in such samples as sera or tissue (liver) for the purposes of defining toxicokinetics [22,45,46] or for diagnostic purposes in the analysis of contaminated feed supplies, tissues, rumen content or fluid samples of poisoned animals ( Figure 4). The use of MS/MS techniques is also beneficial in the structure elucidation of new norditerpenoid alkaloids [23,42,44].…”

Quantification of methyllycaconitine, selective α7 nicotinic receptor antagonist, in rodent plasma and brain tissue by liquid chromatography tandem mass spectrometry – application to neuropharmacokinetics of methyllycaconitine in rats

“…Recently Gardner et al . () employed LC‐MS for trace level analysis of MLA and other alkaloids in sheep serum. Stegelmeier et al .…”