delphinine

Delphinine is a toxic diterpenoid alkaloid found in plants from the Delphinium (larkspur) and Atragene (a clematis) genera, both in the family Ranunculaceae. Delphinine is the principal alkaloid found in Delphinium staphisagria seeds – at one time, under the name stavesacre, a very well known herbal treatment for body lice. It is related in structure and has similar effects to aconitine, acting as an allosteric modulator of voltage gated sodium channels, and producing low blood pressure, slowed heart rate and abnormal heart rhythms. These effects make it highly poisonous ( 1.5–3.0 mg/kg in rabbit and dog; frogs are ~10x more susceptible). While it has been used in some alternative medicines (e.g. in herbal medicine), most of the medical community does not recommend using it due to its extreme toxicity.

==Isolation== One of the earliest reports of the isolation of delphinine, from D. staphisagria, was that of the French chemists Lassaigne and Feneulle, in 1819. A less antique and more accessible report is that of the USDA chemist L. N. Markwood, who also briefly reviewed the earlier isolation work. Notably, these early isolations were carried out without the aid of chromatography, since delphinine crystallizes readily from a petroleum ether extract after the typical acid-base cycling used in traditional plant alkaloid-extraction methods.