Effect of MDL-Type Alkaloids on Tall Larkspur Toxicosis

摘要

Larkspurs (Delphinium spp.) are one of the most serious toxic plant problems on foothill and mountain rangelands in the western USA (Pfister et al. 1999). Total costs to the livestock industry have been estimated to be millions of dollars annually (Nielsen et al. 1994). The toxicity of larkspur plants is due to more than 18 norditerpenoid alkaloids which occur as one of two types: the 7, 8-methylenedioxylycoctonine (MDL)-type including deltaline and 14-O-acetyldictyocarpine (14-OAD) and the N- (methylsuccinimido) anthranoyllycoc-tonine (MSAL)-type including methyllycaconitine (MLA) (Figure 1) (Pfister et al. 1999). Although the MSAL-type alkaloids are much more toxic (Manners et al. 1991, 1993), the MDL-type alkaloids are generally more abundant (Pfister et al. 1999; Gardner et al. 2002).