Distribution of Delphinium occidentale chemotypes and their potential toxicity.

Abstract

Abstract Field samples of D. occidentale populations (1464 plants representing 118 accessions) were collected in the summer of 2007 and 2008 throughout the geographical distribution of D. occidentale, including Utah, Idaho, Montana, Wyoming, Colorado, Nevada and Oregon, USA. These samples, along with 599 herbarium specimens collected from areas representative of the reported geographical distribution of D. occidentale, were analysed by electrospray mass spectrometry. A total of 698 samples containing more than 100 µg methyllycaconitine (MLA)/mg were identified, whereas 1365 samples containing less than 100 µg MLA/mg were obtained. To confirm that these two groups were unique, multivariate statistical methods (MANOVA and discriminant analysis) were used to test for grouping. The pairwise MANOVA revealed the two groups were different. Discriminant analysis also showed clear separation of the two groups based on multiple alkaloids. Samples with more than 100 µg MLA/mg were classified under chemotype A and those samples with less than 100 µg MLA/mg were classified under chemotype B. Chemotype A contained the 7,8-methylenedioxylycoconine (MDL)-type and 7,8-methylenedioxylycoconine (MSAL)-type alkaloids, including MLA, while chemotype B contained principally the MDL-type alkaloids and very little, if any, MLA. Most counties only had samples of one chemotype. However, a number of counties, such as Caribou (Idaho), Lincoln (Wyoming), Sublette (Wyoming) and Fremont (Wyoming), had samples of each chemotype, indicating that these counties serve as a transition zone from south to north. Although these counties had plants with both chemotypes, individual populations from field collections in each county were either chemotype A or B in most cases. Counties that are in the transition zone from east to west, such as Juab and Box Elder counties of Utah, also had samples of both chemotypes but are spatially separated, i.e. chemotype A to the west and chemotype B to the east.