Digitalis 8129 222861559 2008-07-01T13:51:06Z Chieron 5302530 corrected german lemma {{redirect|Foxglove}} {{Taxobox | name = ''Foxglove'' | image = Digitalis purpurea2.jpg | image_width = 180px | image_caption = ''Digitalis purpurea'' (Common Foxglove) | regnum = [[Plantae]] | divisio = [[Flowering plant|Magnoliophyta]] | classis = [[Magnoliopsida]] | ordo = [[Lamiales]] | familia = [[Plantaginaceae]]<ref name="olmstead">{{cite journal | author = Olmstead, R. G., dePamphilis, C. W., Wolfe, A. D., Young, N. D., Elisons, W. J. & Reeves P. A. | title = Disintegration of the Scrophulariaceae | journal= American Journal of Botany| volume= 88| pages = 348–361| year=2001 | url = http://www.amjbot.org/cgi/content/full/88/2/348 | doi = 10.2307/2657024 | pmid = 11222255}}</ref> | genus = '''''Digitalis''''' | genus_authority = [[Carolus Linnaeus|L.]] | subdivision_ranks = Species | subdivision = About 20 species, including:<br/> ''[[Digitalis cariensis]]''<br/> ''[[Digitalis ciliata]]''<br/> ''[[Digitalis davisiana]]''<br/> ''[[Digitalis dubia]]''<br/> ''[[Digitalis ferruginea]]''<br/> ''[[Digitalis grandiflora]]''<br/> ''[[Digitalis laevigata]]''<br/> ''[[Digitalis lanata]]''<br/> ''[[Digitalis leucophaea]]''<br/> ''[[Digitalis lutea]]''<br/> ''[[Digitalis obscura]]''<br/> ''[[Digitalis parviflora]]''<br/> ''[[Digitalis purpurea]]''<br/> ''[[Digitalis thapsi]]''<br/> ''[[Digitalis trojana]]''<br/> ''[[Digitalis viridiflora]]'' }} '''''Digitalis''''' is a genus of about 20 species of [[herb]]aceous [[Perennial plant|perennials]], shrubs, and [[Biennial plant|biennials]] that are commonly called '''foxgloves'''. The genus was traditionally placed in the figwort family [[Scrophulariaceae]], but upon review of [[phylogenetic]] research, it has now been placed in the much enlarged family [[Plantaginaceae]].<ref name="olmstead"/> The genus is native to [[Europe]], western and central [[Asia]], and northwestern [[Africa]]. The scientific name means "finger-like" and refers to the ease with which a [[flower]] of ''Digitalis purpurea'' can be fitted over a human fingertip. The flowers are produced on a tall spike, are tubular, and vary in colour with species, from purple to pink, white, and yellow. The best-known species is the [[Common Foxglove]], ''Digitalis purpurea''. It is a [[biennial plant|biennial]], often grown as an [[ornamental plant]] due to its showy [[flower]]s, that range in colour from purples through to whites, with variable marks and spotting. The first year of growth produces only the long, basal leaves. In the second year, the erect leafy stem 0.5-2.5 m tall develops. The [[larva]]e of the [[Foxglove Pug]] feed on the flowers of ''Digitalis purpurea''. Other [[Lepidoptera]] species feed on the leaves including [[Lesser Yellow Underwing]]. The term '''digitalis''' is also used for preparations containing [[cardiac glycoside]]s, particularly [[digoxin]], extracted from plants of this genus. == Medicinal use == Medicines from foxgloves are called "[[Digitalin]]". The use of ''[[Digitalis purpurea]]'' extract containing [[cardiac glycoside]]s for the treatment of [[heart]] conditions was first described by [[William Withering]], in 1785, which is considered the beginning of modern therapeutics (Silverman)<ref name=Silverman>. In contemporary [[medicine]], a purer form of digitalis (usually [[digoxin]]) is obtained from ''Digitalis lanata.''</ref><ref name=Hollman>Digoxin comes from Digitalis lanata. Hollman A. ''BMJ'' 1996;312:912. online version accessed 18 Oct 2006 [http://bmj.bmjjournals.com/cgi/content/full/312/7035/912]</ref> It is used to increase cardiac contractility (it is a positive [[inotrope]]) and as an [[antiarrhythmic agent]] to control the heart rate, particularly in the irregular (and often fast) [[atrial fibrillation]]. It is therefore often prescribed for patients in atrial fibrillation, especially if they have been diagnosed with [[heart failure]]. A group of pharmacologically active compounds are extracted mostly from the leaves of the second year's growth, and in pure form are referred to by common chemical names such as '''''[[digitoxin]]''''' or '''''[[digoxin]]''''', or by brand names such as ''Crystodigin'' and ''Lanoxin'', respectively. The two drugs differ in that Digoxin has an additional [[hydroxyl]] group at the C-3 position on the B-ring (adjacent to the pentane). Both molecules include a [[lactone]] and a triple-repeating [[sugar]] called a [[glycoside]]. Digitalis works by inhibiting [[sodium-potassium ATPase]]. This results in an increased intracellular concentration of sodium, which in turn increases intracellular [[calcium]] by passively decreasing the action of the sodium-calcium exchanger in the [[sarcolemma]]. The increased intracellular calcium gives a positive [[inotropic]] effect. It also has a vagal effect on the [[parasympathetic nervous system]], and as such is used in reentrant [[cardiac arrhythmia]]s and to slow the ventricular rate during [[atrial fibrillation]]. The dependence on the vagal effect means that digitalis is not effective when a patient has a high [[sympathetic nervous system]] drive, which is the case with acutely ill persons, and also during exercise. Digitalis toxicity (''Digitalis intoxication'') results from an overdose of digitalis and causes anorexia, nausea, vomiting and diarrhea, as well as sometimes resulting in [[xanthopsia]] (jaundiced or yellow vision) and the appearance of blurred outlines (halos). [[Bradycardia]] also occurs. Because a frequent side effect of digitalis is reduction of appetite, some individuals have used the drug as a weight loss aid. Digitalis is a classic example of a drug derived from a plant formerly used by folklorists and herbalists: herbalists have largely abandoned its use because of its narrow [[therapeutic index]] and the difficulty of determining the amount of active drug in herbal preparations. Once the usefulness of digitalis in regulating pulse was understood, it was employed for a variety of purposes, including the treatment of [[epilepsy]] and other seizure disorders, now considered inappropriate. == Toxicity == [[Image:Digitalis purpurea Koehler drawing.jpg|thumb|right|''Digitalis purpurea'' drawings by [[Köhler's Medicinal Plants|Franz Köhler]]]] Depending on the species, the digitalis plant may contain several deadly physiological and chemically related [[cardiac glycosides|cardiac]] and [[steroidal glycosides]]. Thus, the digitalis has earned several more sinister monikers: ''Dead Man’s Bells'', and ''Witches’ Gloves''. The entire plant is [[poisonous]] (including the roots and seeds), although the leaves of the upper stem are particularly potent, with just a nibble being enough to potentially cause death. Early symptoms of ingestion include [[nausea]], [[vomiting]], [[Anorexia (symptom)|anorexia]], [[diarrhea]], abdominal pain, wild hallucinations, [[delirium]], and severe headache. Depending on the severity of the toxicosis the victim may later suffer irregular and slow pulse, [[tremors]], various cerebral disturbances, especially of a visual nature (unusual colour visions with objects appearing yellowish to green, and blue halos around lights), [[convulsions]], and deadly disturbances of the heart. For a case description, see the paper by Lacassie.<ref name=Lacassie>A non-fatal case of intoxication with foxglove, documented by means of liquid chromatography-electrospray-mass spectrometry. Lacassie E et al, ''J Forensic Sci.'' 2000 Sep;45(5):1154-8. Abstract accessed online 19 Sep 2006. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=11005196&query_hl=13&itool=pubmed_DocSum]</ref> There have been instances of people confusing digitalis with the harmless ''[[Symphytum]]'' (comfrey) plant (which is often brewed into a tea) with fatal consequences. Other fatal accidents involve children drinking the water in a vase containing digitalis plants. Drying does not reduce the toxicity of the plant. The plant is toxic to animals including all classes of livestock, as well as cats and dogs. Digitalis poisoning can cause [[heart block]] and [[bradycardia]] (lowered heart rate) and [[tachycardia]] (increased heart rate). It can cause either, depending on the dose and the condition of one's heart. It should however be noted, that electric cardioversion (to "shock" the heart) is generally not indicated in ventricular fibrillation in digitalis toxicity, as it can increase the dysrhythmia in digitalis toxicity. Also, the classic drug of choice (www.erc.edu) for VF (ventricular fibrillation) in emergency setting, [[amiodarone]] (cordarone(R)) can worsen the dysrhythmia caused by digitalis, therefore, the second choice drug [[Lidocaine]] (100mg) is to be used.{{Fact|date=January 2008}} == Use in molecular biology as digoxigenin == [[Digoxigenin]] (DIG) is a steroid found exclusively in the flowers and leaves of the plants ''[[Digitalis purpurea]]'' and ''[[Digitalis lanata]]''. It is used as a molecular probe to detect DNA or RNA. It can easily be attached to nucleotides by chemical modifications. DIG molecules are often linked to [[uridine]] [[nucleotides]]; DIG labeled [[uridine]] (DIG-U) can then be incorporated into [[RNA]] probes via [[in vitro transcription]]. Once [[Nucleic acid hybridization|hybridisation]] occurs ''in situ'', [[RNA]] probes with the incorporated DIG-U can be detected with anti-DIG [[antibodies]] that are conjugated to [[alkaline phosphatase]]. To reveal the hybridised transcripts, [[alkaline phosphatase]] can be reacted with a [[chromogen]] to produce a colour precipitate. [[Image:Digitalis lutea 100705.jpg|thumb|right|''[[Digitalis lutea]]'']] ==See also== * [[List of plants poisonous to equines]] ==References== {{reflist}} *Richard B. Silverman, The Organic Chemistry of Drug Design and Drug Action. *''Flora of Turkey''. Edinburgh University Press. ==External links== {{Commons|Digitalis|''Digitalis''}} {{Wiktionarypar|digitalis}} *[http://rbg-web2.rbge.org.uk/cgi-bin/nph-readbtree.pl/feout?FAMILY_XREF=&GENUS_XREF=Digitalis&SPECIES_XREF=&TAXON_NAME_XREF=&RANK=species Flora Europaea: ''Digitalis'' species list] *[http://www.bris.ac.uk/Depts/Chemistry/MOTM/digitalis/digtalis.htm Molecule of the Month - Digitalis] *[http://www.emedicine.com/PED/topic590.htm eMedicine link] *[http://plants.usda.gov/java/profile?symbol=DILA3 Grecian Foxglove] USDA Noxious Weed List. *[http://plants.usda.gov/java/profile?symbol=DIPU Purple Foxglove] USDA Noxious Weed List. [[Category:Antiarrhythmic agents]] [[Category:Medicinal plants]] [[Category:Plantaginaceae]] [[Category:Poisonous plants]] [[ca:Digitalis]] [[da:Fingerbøl-slægten]] [[de:Fingerhüte]] [[es:Digitalis]] [[eo:Digitalo]] [[fr:Digitale]] [[hsb:Naporst]] [[id:Digitalis]] [[it:Digitalis]] [[lt:Rusmenė]] [[nl:Vingerhoedskruid (geslacht)]] [[ja:ジギタリス]] [[pl:Naparstnica]] [[pt:Digitalis]] [[ro:Degeţel]] [[sq:Digitalis]] [[tr:Yüksük otu]]