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Phytolacca americana

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Phytolacca americana, the American pokeweed or simply pokeweed, is a herbaceous perennial plant in the pokeweed family Phytolaccaceae growing up to 8 ft (2.4m) in height. It is native to the eastern United States and has significant toxicity.

It has simple leaves on green to red or purplish stems and a large white taproot. The flowers are green to white, followed by purple to almost black berries which are a food source for songbirds such as gray catbird, northern mockingbird, northern cardinal, and brown thrasher, as well as other birds and some small animals (i.e., to species that are unaffected by its mammalian toxins).

Pokeweed is native to eastern North America, the Midwest, and the Gulf Coast, with more scattered populations in the far West. It is also naturalized in parts of Europe and Asia. It is considered a major pest species by farmers.Template:Citation needed lead Additionally, pokeweed poses a danger to human and animal populations via poisoning; with toxicity levels increasing as the plant matures, and poisonous fruit. This very poisonous purple-red ripe fruit poses danger to children and animals who may want to taste it. Even so, it is used as an ornamental in horticulture, and it provokes interest for the variety of its natural products (toxins and other classes), for its ecological role, its historical role in traditional medicine, and for some utility in biomedical research (e.g., in studies of pokeweed mitogen). In the wild, it is easily found growing in pastures, recently cleared areas, and woodland openings, edge habitats such as along fencerows, and in waste places.

General description

Pokeweed berries
Mature Pokeweed.jpg

Pokeweed is a member of the Phytolaccaceae, or broader pokeweed family, and is a native herbaceous perennial plant,<ref name=Owen88/> that is large, growing up to Template:Convert in height.<ref name=Owen88/> One to several branches grow from the crown of a thick, white, fleshy taproot, each a "stout, smooth, green to somewhat purplish stem;" with simple, entire leaves with long petioles alternately arranged along the stem.<ref name=Owen88/>

Pokeweeds reproduce only by their seeds (large glossy black, and lens-shaped), contained in a fleshy, 10-celled, purple-to-near-black berry with crimson juice. The flowers are perfect, radially symmetric, white or green, with 4-5 sepals and no petals. The flowers develop in elongated clusters termed racemes.<ref name=Owen88/><ref>The flower have 10 stamens and a 10-cell pistil, that gives rise to the 10-celled berry</ref> The seeds have a long viability and can germinate after many years in the soil.

Birds are unaffected by the natural chemicals contained in the berries (see below),<ref name=Owen88/> and eat them, dispersing the seeds. Seed are also found in commercial seed (e.g., vegetable seed packets).<ref name=Owen88/> The berries are reported to be a good food source for songbirds and other bird species and small animals unaffected by its toxins.<ref name=MatthewsGOV87>Nancy L. Matthews, 1987, "Appendix F: Habitat Assessment Manual," in Report: Anne Arundel Co., Offc. Planning and Zoning, Environmental and Special Projects Div., to Office of Coastal Resources Management, NOAA and State of Maryland Chesapeake Bay Critical Area Commission, August 1987, 9 pages, passim see [1], accessed 2 May 2015.</ref> Distribution via birds is thought to account for the appearance of "single, isolated plants" in areas that had otherwise not been populated by pokeweed.<ref name=Owen88/>

Names

P. americana is known as pokeberry,<ref name=Owen88/><ref name=GRIN>USDA-ARS, 2015, "Taxon: Phytolacca americana L.," at National Genetic Resources Program.Germplasm Resources Information Network - (GRIN) [Online Database], National Germplasm Resources Laboratory, Beltsville, Maryland, see [2]Template:Dead link, accessed 2 May 2015.</ref> poke root,<ref name=GRIN/> Virginia poke (or simply poke),<ref name=GRIN/><ref name=Hortus3>Bailey, L.H., Bailey, E.Z., and the staff of the Liberty Hyde Bailey Hortorium, 1976, Hortus third: A concise dictionary of plants cultivated in the United States and Canada, New York, NY:Macmillan, Template:ISBN, see [3], accessed 2 May 2015.</ref> pigeonberry,<ref name=GRIN/><ref name=Hortus3/> inkberry,<ref name=Owen88/> redweed or red ink plant.<ref name=Hortus3/> When used in Chinese medicine, it is called chuíxù shānglù (垂序商陸).<ref name=GRIN/><ref>Further unlisted names that appear in Hortus Third (Bailey, Bailey, et al., 1976, op. cit.) include: cancer jalap, oakum, garget, pocan, and scoke.</ref><ref>Further unlisted names that appear at WebMD include American Nightshade, American Spinach, Baie de Phytolaque d’Amérique, Bear's Grape, Branching Phytolacca, Cancer Jalap, Chongras, Coakum, Coakum-Chorngras, Cokan, Crowberry, Épinard de Cayenne, Épinard des Indes, Faux Vin, Fitolaca, Garget, Herbe à la Laque, Hierba Carmin, Jalap, Kermesbeere, Laque, Phytolacca Berry, Phytolacca americana, Phytolacca decandra, Phytolaque Américaine, Phytolaque à Baies, Phytolaque Commun, Phytolaque d'Amérique, Pocan, Raisin d'Amérique, Red Plant, Scoke, Skoke, Teinturier, Teinturière, Vigne de Judée. See WebMD, 2015, "Pokeweed," at WebMD: Vitamin and Supplement (online), [4], accessed 2 May 2015.</ref> The plant and its cooked leaves are also called poke salad.

Toxicity, poisoning and mortality

All parts of the plant are toxic and pose risks to human and mammalian health.<ref name="oardc">John Cardina, Cathy Herms, Tim Koch & Ted Webster, 2015, "Entry: Common Pokeweed, Phytolacca americana," in Ohio Perennial and Biennial Weed Guide, Wooster, OH:Ohio Agricultural Research and Development Center (OARDC), see OARDC Pokeweed, accessed 2 May 2015.</ref><ref name=Owen88>Michael D.K. Owen, 1988, "Pokeweed (Phytolacca americana L.)," Publication Pm-746 of the Iowa State University Extension Service, Ames, IA:Iowa State University, see [5], accessed 2 May 2015</ref><ref name=HellerNLM13>Jacob L. Heller, 2103, "Pokeweed poisoning," at MedlinePlus (online), October 21, 2013, see [6], accessed 2 May 2015.</ref><ref name=CPPIS13>CBIF CPPIS, 2013, "All Plants (Scientific Name): Phytolacca americana," at Canadian Biodiversity Information Facility, Species Bank, Canadian Poisonous Plants Information System, (online), June 5, 2013, see [7], accessed 2 May 2015.</ref><ref name=Dasgupta11>Amitava Dasgupta, 2011, Effects of Herbal Supplements on Clinical Laboratory Test Results, Volume 2, Patient Safety, Walter de Gruyter, Template:ISBN, see [8], accessed 2 May 2015.</ref> In summary, the poisonous principles are found in highest concentrations in the rootstock, then in leaves and stems and then in the ripe fruit.<ref name="oardc"/><ref name=HellerNLM13/> The plant generally gets more toxic with maturity,<ref name="oardc"/> with the exception of the berries (which have significant toxicity even while green).<ref name=Dasgupta11/>

Children may be attracted by clusters of berries.<ref name=Owen88/> Ohio Agricultural Research and Development Center (OARDC) note that<ref name="oardc"/>Template:Quote Pokeweed is to be avoided during pregnancy and children consuming even one berry may require emergency treatment.<ref name=autogenerated1/> The plant sap can cause dermatitis in sensitive people.<ref name=autogenerated1/>

Birds are apparently immune to this poison.<ref name=Owen88/> The plant is not palatable to animals and is avoided unless little else is available, or if it is in contaminated hay, but horses, sheep and cattle have been poisoned by eating fresh leaves or green fodder, and pigs have been poisoned by eating the roots.<ref name="oardc"/>

Human deaths resulting from pokeweed consumption are uncommon,Template:Citation needed but cases of emesis and catharsis are known,Template:Citation needed and a child who consumed crushed seeds in a juice is reported to have died.Template:Citation needed If death occurs, it is usually due to respiratory paralysis.<ref name=Owen88/>

Historically, pokeweed poisonings were common in eastern North America during the 19th century, especially from the use of tinctures as antirheumatic preparations and from ingestion of berries and roots that were mistaken for parsnip, Jerusalem artichoke, or horseradish.<ref>Template:Cite journal</ref>

Symptoms and response to poisoning

Owen states:<ref name=Owen88/>Template:Quote

The OARDC staff scientists note that immediate and subsequent symptoms of poisoning from pokeweed include "a burning sensation in the mouth, salivation, gastrointestinal cramps, and vomiting and bloody diarrhea," and that depending upon the amount consumed, more severe symptoms can occur, including "anemia, altered heart rate and respiration, convulsions and death from respiratory failure."<ref name="oardc"/> If only small quantities of the plant or its extracts are ingested, people and animals may recover within 1 to 2 days.<ref name="oardc"/><ref>One local scientific study performed in Oklahoma in 1962 concluded that the oral lethal dose of fresh poke berries in mice "appeared to be about 300 gm/kg body weight and for the dry berries about 100 gm/kg body weight." and that the "liquid extract of Poke berries was approximately 80 times as toxic when injected intraperitoneally as when given orally". See Template:Cite journal</ref>

Habitat and range

Pokeweed is native to eastern North America, the Midwest, the Gulf Coast, and the West coast states of the USA.<ref>Template:Cite web</ref>

Morphology

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a cluster of Pokeweed berries

Plant Type: Perennial herbaceous plant which can reach a height of Template:Convert, but is usually Template:Convert to Template:Convert. However, the plant must be a few years old before the root grows large enough to support this size. The stem is often red as the plant matures. There is an upright, erect central stem early in the season, which changes to a spreading, horizontal form later in the season with the weight of the berries. Plant dies back to roots each winter. Stem has a chambered pith.

Leaves: The leaves are alternate with coarse texture with moderate porosity. Leaves can reach sixteen inches in length. Each leaf is entire. Leaves are medium green and smooth with what some characterize as an unpleasant odor.

Flowers: The flowers have 5 regular parts with upright stamens and are up to Template:Convert wide. They have white petal-like sepals without true petals, on white pedicels and peduncles in an upright or drooping raceme, which darken as the plant fruits. Blooms first appear in early summer and continue into early fall.

Fruit: A shiny dark purple berry held in racemose clusters on pink pedicels with a pink peduncle. Pedicels without berries have a distinctive rounded five part calyx. Fruits are round with a flat indented top and bottom. Immature berries are green, turning white and then blackish purple.

Root: Thick central taproot which grows deep and spreads horizontally. Rapid growth. Tan cortex, white pulp, moderate number of rootlets. Transversely cut root slices show concentric rings. No nitrogen fixation ability.<ref name=GRIN/>Template:Failed verification<ref name=autogenerated1>Anon., 2015, "Entry: Phytolacca americana - L.," at Plants For A Future (organizational webpage), see [9], accessed 2 May 2015.Template:Better source</ref>

Natural products

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Various sources discuss notable chemical constituents of the plant.<ref>Bensky, Dan, Steven Clavey, Steven & Stoger, Erich, 2004, Chinese Herbal Medicine, Materia Medica, 3rd Ed., Eastland Press.Template:Full citation needed</ref>Template:Full citation neededTemplate:Better source Owen of Iowa State University notes that the "entire pokeweed plant contains a poisonous substance similar to saponin" and that the "alkaloid phytolaccine also occurs in small amounts."<ref name=Owen88/> Heller at the National Library of Medicine notes the two natural products, the alkaloid phytolaccatoxin and phytolaccagenin, as contributing to human poisoning.<ref name=HellerNLM13/> The Canadian Poisonous Plants Information System echoes the information about phytolaccine and phytolaccatoxin.<ref name=CPPIS13/>

Other toxic components include triterpene saponins based on the triterpene genins, phytolaccagenin as noted, and jaligonic acid, phytolaccagenic acid (phytolaccinic acid), esculentic acid, and pokeberrygenin,<ref name=KangWoo80>Template:Cite journal</ref> and phytolaccasides A, B, D, E, and G, and phytolaccasaponins B, E, and G.<ref>Template:Cite journalTemplate:Primary source inline</ref>Template:Primary source inline<ref>Tang, W. & Eisenbrand, G., 1992, Chinese Drugs of Plant Origin: Chemistry, Pharmacology, and Use in Traditional and Modern Medicine, New York, NY: Springer-Verlag, p. 765.</ref>

Triterpene saponins isolated from the berries of pokeweed uncharacterized as to toxicity include esculentoside E; and phytolaccasides C and F, and oleanolic acid, and 3-oxo-30-carbomethoxy-23-norolean-12-en-28-oic acid.<ref name=KangWoo80/> Triterpene alcohols isolated include α-spinasterol and its glucoside, α-spinasteryl-β-D-glucoside, and a palmityl-derivative, 6-palmytityl-α-spinasteryl-6-D-glucoside, as well as a similarly functionalized stigmasterol derivative, 6-palmityl-Δ7-stigmasterol-Δ-D-glucoside.<ref name=KangWoo80/>

Other than starch and various tannins, other small molecule natural products isolated from pokeweed include canthomicrol, astragalin, and caryophyllene.<ref name=KangWoo80/> Seeds contain the phenolic aldehyde caffeic aldehyde.<ref>Woo, W.S., Kang, S.S., 1979. A new phenolic aldehyde from the seeds of Phytolacca americana. Soul Taehakkyo Saengyak Yonguso Opjukjip 18, 30–31.</ref>

Proteins of interest include various lectins, protein PAP-R, and pokeweed mitogen (PWM),Template:Citation needed as well as a toxic glycoprotein.<ref name=CPPIS13/>

Uses

Horticultural and ecological utility

Pokeweed berries are reported to be a good food source for songbirds such as gray catbird (Dumetella carolinensis), northern mockingbird (Mimus polyglottos), northern cardinal (Cardinalis cardinals), brown thrasher (Toxostoma rufum), other bird species including mourning dove (Zenaida macroura), and cedar waxwing (Bombycilla cedrorum). Small mammals apparently tolerant of its toxins include raccoon, opossum, red and gray fox, and the white-footed mouse.<ref name=MatthewsGOV87/><ref>Other birds reported to include pokeweed in their diets include bluebirds, crested flycatchers, fish crows, hairy woodpeckers, kingbirds, phoebes, robins, starlings, and yellaw-breasted chats, see Matthews, 1987, op. cit.</ref>

Pokeweed is used as a sometime food source by the larvae of some Lepidoptera species, including the giant leopard moth (Hypercompe scribonia).<ref>Donald W. Hall, 2015, "Giant woolly bear (larva), giant or great leopard moth (adult) [scientific name: Hypercompe scribonia (Stoll 1790) (Lepidoptera: Erebidae: Arctiinae)]," at Institute of Food and Agricultural Sciences: Featured creatures, Gainesville, FL:Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Table 1, see Template:Cite web, accessed 2 May 2–15.</ref>

Some pokeweeds are grown as ornamental plants, mainly for their attractive berries. A number of cultivars have been selected for larger fruit panicles.<ref>Template:Cite web</ref>

Folk and alternative medicine

Owen notes that "Indians and early settlers used the root in poultices and certain drugs for skin diseases and rheumatism."<ref name=Owen88/>

The late 19th century herbal, the King's American Dispensatory, describes various folk medical uses that led individuals to ingest pokeberry products.<ref name=autogenerated3>John King, Harvey Wickes Felter & John Uri Lloyd, 1898, "Entry: Phytolacca," in King's American Dispensatory, Cincinnati : Ohio Valley Co., see [10] and [11], accessed 2 May 2015.</ref> Phytolacca extract was advertised as a prescription weight loss drug in the 1890s.<ref>Template:Cite book</ref>

Pokeweed is promoted in alternative medicine as a dietary supplement that can treat a wide range of maladies including mumps, arthritis and various skin conditions.<ref name=acs/> While pokeweed has been subject to laboratory research, there is no medical evidence that it has any beneficial effect on human health.<ref name=acs>Template:Cite book</ref>

Food uses

Woman preparing poke salad

Poke is a traditional southern Appalachian food. The leaves and stems of very young plants can both be eaten, but must be cooked, usually boiled three times in fresh water each time. The leaves have a taste similar to spinach; the stems taste similar to asparagus. To prepare stems, harvest young stalks prior to chambered pith formation, carefully peel the purple skin away, then chop the stalk up and fry in meal like okra. Traditionally, poke leaves are boiled, drained, boiled again, then fatback is added and cooked some more to add flavor. Poisonings occur from failure to drain the water from the leaves at least once. Preferably they should be boiled, drained, and water replaced two or more times.

As noted by the OARDC staff scientists:<ref name="oardc"/>Template:Quote

Although all parts of the plant are considered toxic and the root is never eaten and cannot be made edible,Template:Citation needed the late 19th century herbal, the King's American Dispensatory, describes various folk medical uses that led individuals to ingest pokeberry products,<ref name="autogenerated3"/> and festivals still celebrate the plant's use in its historical food preparations (see below). AuthoritiesTemplate:Who advise against eating pokeweed even after thrice boiling, as traces of toxins may still remain,Template:Citation needed and all agree pokeweed should never be eaten uncooked.Template:Citation needed

Other uses

Plant toxins from Phytolacca are being explored as a means to control zebra mussels.<ref>Harold H. Lee, Lemma Aklilu, and Harriett J. Bennett, 1992, The use of Endod (Phytolacca dodecandra) to Control the Zebra Mussels (Dreissena polymorpha), Chapter 37, pp. 643-656, in Zebra Mussels Biology, Impacts, and Control, Thomas F. Nalepa & Don W. Schloesser, Eds., Boca Raton, FL:CRC Press, Template:ISBN, see [12], accessed 5 May 2015.</ref><ref>Template:Cite patent</ref>

The toxic extract of pokeweed berries can be processed to yield a red ink or dye.<ref>Pesha Black & Micah Hahn, 2004, "Pokeweed, Phytolacca americana, Family: Phytolaccaceae," at [Guide to] Practical Plants of New England (student project pages), see Template:Cite web, accessed 2 May 2015.</ref><ref>Template:Cite web</ref><ref>Template:Cite book</ref>

During the middle of the 19th century wine often was coloured with juice from pokeberries.<ref>Nilsson et al. 1970. "Studies into the pigments in beetroot (Beta vulgaris L. ssp. vulgaris var. rubra L.)"</ref>

Cultural significance

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In music

A 1969 hit written and performed Tony Joe White, "Polk Salad Annie", is about poke sallet, the cooked greens-like dish made from pokeweed. The lyrics include:<ref name=Doppelbauer08fan>Template:Cite web</ref><ref>Template:Cite web</ref>

And in the fields looks somethin' like a turnip green
And everybody calls it polk salad, polk salad

Elvis Presley covered the song.

In local Southern festivals

Poke salad festivals are held annually in several small southern communities, in remembrance of the plant and its historic role, festivals that have evolved to be local community celebrations only remotely related to the plant as a food or medicinal (e.g.,<ref name=APFSA>APSFA, 2015, "Schedule of Events," at The Annual Poke Salad Festival Association, Annual Poke Salad Festival, Blanchard, Louisiana, at Template:Cite web, accessed 2 May 2015.</ref> and individual festival references below). Published locations for the continuing festivals include:

Gallery

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References

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Further reading and viewing

  • P.A.G.M. De Smet, 1993, "Phytolacca americana," in Adverse Effects of Herbal Drugs, Volume 2 (Peter A. G. M. Smet, Konstantin Keller, Rudolf Hänsel, & R. Frank Chandler, Eds.), Berlin:Springer Science & Business Media, Template:ISBN, see [13], accessed 2 May 2015.
  • ACS, 2008, "Entry: Pokeweed," at Find Support & Treatment; Treatments and Side Effects Complementary and Alternative Medicine; Herbs, Vitamins, and Minerals, see ACS Pokeweed entry, accessed 2 May 2015.
  • Tyler, V. E.; Brady, L. R. & Robbers, J. E., 1988, "Poisonous plants," in Pharmacognosy, 9th ed. Philadelphia:Lea and Febiger, Chapter 15, pp. 438–455.
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  • "Tony Joe White - Polk Salad Annie," performance, date unknown, at [14], accessed 2 May 2015.
  • "Tony Joe White and Johnny Cash," performance, 1970, "Polk Salad (Poke Salit) Annie," from Johnny Cash Show, episode no. 27, April 8, 1970, at LiveLeak (online), see [15], accessed 2 May 2015.
  • Brennan Carley, 2014, "Foo Fighters Join Tony Joe White on Bluesy ‘Polk Salad Annie’ on ‘Letterman’," Spin (online), October 16, 2014, see [16], accessed 2 May 2015.

External links

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