Aconitum napellus

Aconitum napellus, monk's-hood,[2] aconite or wolfsbane, is a species of highly toxic flowering plant in the genus Aconitum of the family Ranunculaceae, native and endemic to western and central Europe. It is an herbaceous perennial plant growing to 1 m (3 ft 3 in) tall, with hairless stems and leaves. The leaves are rounded, 5–10 cm (2.0–3.9 in) diameter, palmately divided into five to seven deeply lobed segments. The flowers are dark purple to bluish-purple, narrow oblong helmet-shaped, 1–2 cm (0.39–0.79 in) tall. Plants native to Asia and North America formerly listed as A. napellus are now regarded as separate species. The plant is extremely poisonous in both ingestion and skin contact.

Aconitum napellus

Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Ranunculales
Family: Ranunculaceae
Genus: Aconitum
Species:
A. napellus
Binomial name
Aconitum napellus

Cultivation

Aconitum napellus is grown in gardens in temperate zones for its spiky inflorescences that are showy in early-mid summer, and its attractive foliage. There are white and rose colored forms in cultivation too. The cultivar 'Spark's Variety' has gained the Royal Horticultural Society's Award of Garden Merit.[3][4]

Subspecies

Nine subspecies are accepted by the Flora Europaea:[5]

  • Aconitum napellus subsp. napellus, south-western Britain
  • Aconitum napellus subsp. corsicum (Gáyer) W.Seitz, Corsica
  • Aconitum napellus subsp. firmum (Rchb.) Gáyer, Central and eastern Europe
  • Aconitum napellus subsp. fissurae (Nyár.) W.Seitz, Balkans to south-western Russia
  • Aconitum napellus subsp. hians (Rchb.) Gáyer, Central Europe
  • Aconitum napellus subsp. lusitanicum Rouy, south-western Europe
  • Aconitum napellus subsp. superbum (Fritsch) W.Seitz, western Balkans
  • Aconitum napellus subsp. tauricum (Wulfen) Gáyer, Eastern Alps, southern Carpathians (declared as an own species Aconitum tauricum by other sources[6][7])
  • Aconitum napellus subsp. vulgare (DC.) Rouy & Foucaud, Alps, Pyrenees, northern Spain

Uses

Aconitum napellus is grown in gardens for its attractive spike-like inflorescences and showy blue flowers.[8] It is a cut flower crop used for fresh cutting material and sometimes used as dried material. The species has a low natural propagation rate under cultivation and is propagated by seed or by removing offsets that are generated each year from the rootstocks. The use of micropropagation protocols has been studied.[9] This species has been crossed with other Aconitums to produce attractive hybrids for garden use, including Aconitum × cammarum.[10]

Seeds

Like other species in the genus, A. napellus contains several poisonous compounds, including enough cardiac poison that it was used on spears and arrows for hunting and battle in ancient times.[11] Persian physician Avicenna (980–1037) wrote that arrows dipped in the sap were used to kill and Dr Antonio Guaineri in one of the first medical dictionaries, 'Practica' wrote that arrows that had the poison from roots of the plant were used to kill wild goats in Italy.[12] A. napellus has a long history of use as a poison, with cases going back thousands of years.[13] During the ancient Roman period of European history, the plant was often used to eliminate criminals and enemies, and by the end of the period it was banned and anyone growing A. napellus could have been legally sentenced to death.[14] Aconites have been used more recently in murder plots; they contain the chemical alkaloids aconitine, mesaconitine, hypaconitine and jesaconitine, which are highly toxic.[15] It was also used in a recent Sherlock Holmes book plot.[16]

Toxicology

Marked symptoms may appear almost immediately, usually not later than one hour, and "with large doses, death is almost instantaneous".[17] Death usually occurs within two to six hours in fatal poisoning (20 to 40 mL of tincture may prove fatal).[18] The initial signs are gastrointestinal including nausea, vomiting, and diarrhea. This is followed by a sensation of burning, tingling, and numbness in the mouth and face, and of burning in the abdomen.[19] In severe poisonings pronounced motor weakness occurs and cutaneous sensations of tingling and numbness spread to the limbs. Cardiovascular features include hypotension, sinus bradycardia, and ventricular arrhythmias. Other features may include sweating, dizziness, difficulty in breathing, headache, and confusion. The main causes of death are ventricular arrhythmias and asystole, paralysis of the heart or of the respiratory center.[18][20] The only post-mortem signs are those of asphyxia.[19]

Treatment of poisoning is mainly supportive. All patients require close monitoring of blood pressure and cardiac rhythm. Gastrointestinal decontamination with activated charcoal can be used if given within one hour of ingestion.[21] The major physiological antidote is atropine, which is used to treat bradycardia. Other drugs used for ventricular arrhythmia include lidocaine, amiodarone, bretylium, flecainide, procainamide, and mexiletine. Cardiopulmonary bypass is used if symptoms are refractory to treatment with these drugs.[20] Successful use of charcoal hemoperfusion has been claimed in patients with severe aconite poisoning.[22]

Poisoning may also occur following picking the leaves without wearing gloves; the aconitine toxin is absorbed easily through the skin. In this event, there will be no gastrointestinal effects. Tingling will start at the point of absorption and extend up the arm to the shoulder, after which the heart will start to be affected. The tingling will be followed by unpleasant numbness. Treatment is similar to poisoning caused by oral ingestion and even handling the plant without gloves has been reported to result in multi-organ failure and death.[23][24]

'Aconitine' is a potent neurotoxin that opens tetrodotoxin sensitive sodium channels. It increases influx of sodium through these channels and delays repolarization, thus increasing excitability and promoting ventricular dysrhythmias.

gollark: Feelings are mostly heuristics for things the brain can't be bothered to work out properly.
gollark: Okay, give me a bit to read context.
gollark: It uses dark sorcery and whatnot to try and get autoreconnection.
gollark: I am ANGRY! PotatOS's new SPUDNET daemon WILL NOT WORK and I do not know why!
gollark: Time for a tasty glass of dihydrogen monoxide containing 184mg magnesium per L!

References
  1. Chappuis, E. (2014). "Aconitum napellus". IUCN Red List of Threatened Species. 2014: e.T165155A57117867. doi:10.2305/IUCN.UK.2014-1.RLTS.T165155A57117867.en.
  2. "BSBI List 2007". Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-01-25. Retrieved 2014-10-17.
  3. "RHS Plant Selector - Aconitum 'Spark's Variety'". Retrieved 17 July 2013.
  4. Bourne, Val (31 July 2009). "How to grow: Aconitum 'Sparks Variety'". The Telegraph. Retrieved 7 June 2020.
  5. Flora Europaea: Aconitum napellus
  6. The Plant List (KEW): Aconitum tauricum (2018-05-03)
  7. Jäger et al.: Rothmaler - Exkursionsflora von Deutschland, Bd. 2. Ed. 20, Spektrum akadem. Verlag.
  8. Datta, Subhash Chandra. 1988 Systematic botany. New Delhi: Wiley Eastern Ltd.
  9. A. A. Watad, M. Kochba, A. Nissim and V. Gaba, "Improvement of Aconitum napellus micropropagation by liquid culture on floating membrane rafts", Journal Plant Cell Reports, Publisher: Springer Berlin / Heidelberg, ISSN 0721-7714 (Print) ISSN 1432-203X (online), Volume 14, Number 6 / March 1995, DOI 10.1007/BF00238594, pages 345–348
  10. Armitage, A. M. 2000. Armitage's garden perennials a color encyclopedia. Portland, Oregon: Timber Press. Pages 19–20.
  11. J Ethnopharmacol. 1981 Nov;4(3):247-336. Arrow poisons in China. Part II. Aconitum--botany, chemistry, and pharmacology. Bisset NG.
  12. Luke DeMaitre Medieval Medicine: The Art of Healing, from Head to Toe (2013), p. 67, at Google Books
  13. "Toxicology in the Old Testament: Did the High Priest Alcimus Die of Acute Aconitine Poisoning?" Authors: Moog F.P.1; Karenberg A.1 Source: Adverse Drug Reactions & Toxicological Reviews (now known as Toxicological Reviews), Volume 21, Number 3, 2002 , pp. 151–156(6) Publisher: Adis International
  14. Roberts, M. F., and Michael Wink. 1998. Alkaloids biochemistry, ecology, and medicinal applications. New York: Plenum Press. Page 18.
  15. CSA Archived December 8, 2008, at the Wayback Machine
  16. Gary Lovisi and Marvin Kaye The Great Detective: His Further Adventures: A Sherlock Holmes Anthology (2012), p. 55, at Google Books
  17. R.D. Mann Modern Drug use: An Enquiry on Historical Principles (1984), p. 66, at Google Books
  18. The Extra Pharmacopoeia Martindale. Vol. 1, 24th edition. London: The Pharmaceutical Press, 1958, page 38.
  19.  One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Aconite". Encyclopædia Britannica. 1 (11th ed.). Cambridge University Press. pp. 151–152.
  20. Chan TY (April 2009). "Aconite poisoning". Clin Toxicol. 47 (4): 279–85. doi:10.1080/15563650902904407. PMID 19514874.
  21. Chyka PA, Seger D, Krenzelok EP, Vale JA (2005). "Position paper: Single-dose activated charcoal". Clin Toxicol. 43 (2): 61–87. doi:10.1081/CLT-51867. PMID 15822758.
  22. Lin CC, Chan TY, Deng JF (May 2004). "Clinical features and management of herb-induced aconitine poisoning". Ann Emerg Med. 43 (5): 574–9. doi:10.1016/j.annemergmed.2003.10.046. PMID 15111916.
  23. "Gardener Nathan Greenway 'died after handling deadly plant'". BBC News. BBC. 7 November 2014. Retrieved 7 November 2014.
  24. "Gardener dies 'after brushing against deadly wolfsbane flower' on millionaire's estate". Independent. 11 November 2014. Retrieved 2 February 2015.
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