Phytolacca americana

Phytolacca americana
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Core eudicots
Order:	Caryophyllales
Family:	Phytolaccaceae
Genus:	Phytolacca
Species:	P. americana
Binomial name
Phytolacca americana L.

American Pokeweed (Phytolacca americana) is a large semi-succulent herbaceous perennial plant growing up to 10 feet (3 meters) in height. It is native to eastern North America, the Midwest, and the Gulf Coast, with more scattered populations in the far West. It is also known as American nightshade, cancer jalap, coakum, garget, inkberry, pigeon berry, pocan bush, poke root, pokeweed, redweed, scoke, red ink plant and chui xu shang lu (in Chinese medicine). Parts of this plant are highly toxic to livestock and humans, and it is considered a major pest by farmers. Nonetheless, some parts can be used as food, medicine or poison.

The plant has a large white taproot, green or red stems, and large, simple leaves. White flowers are followed by purple to almost black berries, which are a good food source for songbirds such as Gray Catbird, Northern Cardinal, Brown Thrasher, and Northern Mockingbird.

Morphology

Plant Type: Perennial herbaceous plant which can reach a height of 10 feet, but is usually four to six feet. The stem is often red as the plant matures. Upright, erect central stem early in the season. 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 chambered pith.^{[citation needed]}

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.^{[citation needed]}

Flowers: The flowers have 5 regular parts with upright stamens and are up to 0.2 inches wide. They have white petal-like sepals without true petals, on white pedicles 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.^{[citation needed]}

Fruit: A shiny dark purple berry held in racemous clusters on pink pedicels with a pink peduncle. Pedicles without berries have a distinctive rounded five part calyx. Berries are pomes, round with a flat indented top and bottom. Immature berries are green, turning white and then blackish purple.^{[citation needed]}

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.^[1][2]

Habitat and range

Broadly distributed in fields and waste places, and usually found in edge habitats. The seeds do not require stratification and are dispersed by berry-feeding birds. Adapted to coarse or fine soils with moderate moisture, high calcium tolerance but low salinity tolerance, pH tolerance from 4.7-8. Grows well in sun or shade and readily survives fire due to its ability to resprout from the roots. In recent years the plant appears to have increased in populated places. Found in most of the United States except the Mountain States, Alaska and Hawaii.^[2][3]

Known constituents

^[2][4]

Triterpene saponins: Phytolaccoside A,B,C,D,E,F,G (esculentoside E), phytolaccagenin, jaligonic acid, esculentic acid, 3-oxo-30-carbomethoxy-23-norolean-12-en-28-oic acid, phytolaccagenic acid, oleanolic acid.^[5]

Triterpene alcohols: alpha spinasterol, alpha spinasteryl-beta-D-glucoside, 6 palmityl-delta7-stigmasterol-delta-D-glucoside, 6 palmytityl-alpha-spinasteryl-6-D-glucoside.

Other: phytolaccatoxin, canthomicrol, astragalin, protein PAP-R, mitogen (a series of glycoproteins), caryophyllene, lectins, tannin, starch.

Nutritional Information per 100 grams dry weight of shoots:^[1]

• Protein: 31g; Fat: 4.8g; Carbohydrate: 44g; Fibre: 0g; Ash: 20.2g;
• Minerals - Calcium: 631 mg; Phosphorus: 524 mg; Iron: 20.2 mg; Magnesium: 0 mg; Sodium: 0 mg; Potassium: 0 mg; Zinc: 0 mg;
• Vitamins - A: 62 mg; Thiamine (B₁): 0.95 mg; Riboflavin (B₂): 3.93 mg; Niacin: 14.3 mg; B₆: 0 mg; C: 1619 mg.

Standardization: Phytolacca is not generally standardized since it is not marketed to public and various properties are being considered for standardization for different uses. For example Phytolaccoside A,B, C et al. from leaves are being considered for antiviral use and Pokeweed antiviral protein, with subtypes taken from leaves in different seasons for AIDS. Oleanolic acid would be the constituent of choice for standardizing for the purposes of cancer since it is present in an ethanol root extract and has significant anticancer properties, for several types of carcinoma as well as leukemia.^[6][7]

Toxicity

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.^[8] Deaths are currently uncommon, although there are cases of emesis and catharsis, but at least one death of a child who consumed crushed seeds in a juice has occurred.

The toxic components of the plant are saponins based on the triterepene genins phytolaccagenin, jaligonic acid, phytolaccagenic acid (phytolaccinic acid), esculentic acid, and pokeberrygenin.^[5] These include phytolaccosides A, B, D, E, and G, and phytolaccasaponins B, E, and G. Phytolaccigenin causes hemagglutination.^[9][10]

Uses

Food uses

Although the seeds are highly toxic, the berries are often cooked into a jelly or pie, and seeds are strained out or pass through unless bitten. Cooking is believed to inactivate toxins in the berries by some and others attribute toxicity to the seeds within the berries. The leaves of young plants are sometimes collected as a spring green potherb and eaten after repeated blanchings. Shoots are also blanched with several changes of water and eaten as a substitute for asparagus. They become cathartic as they advance to maturity.^[11] The cooked greens are sold commercially in the South, but any food use of the plant is controversial because of toxins in the plant.

Other uses

A patent has been filed to use poke toxins to control zebra mussels.^[12]

Gallery

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  Berries

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  Ripe fruit

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  Flower

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  Young fruit

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  Brush

References

1. ^ ^{a b} Phytolacca americana - Plants For A Future database report
2. ^ ^{a b c} Phytolacca americana information from NPGS/GRIN
3. ^ PLANTS Profile for Phytolacca americana (American pokeweed) | USDA PLANTS
4. ^ Chinese Herbal Medicine, Materia Medica 3rd Edition. Bensky, Dan; Steven Clavey, Erich Stoger. Eastland Press, 2004.
5. ^ ^{a b} Kang SS, Woo WS (1980). "Triterpenes from the berries of Phytolacca americana". J Nat Prod 43 (4): 510–3. doi:10.1021/np50010a013. 
6. ^ Barbieri L, Aron GM, Irvin JD, Stirpe F (April 1982). "Purification and partial characterization of another form of the antiviral protein from the seeds of Phytolacca americana L. (pokeweed)". Biochem. J. 203 (1): 55–9. PMC 1158192. PMID 7103950. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1158192. 
7. ^ HerbalGram: The Journal of the American Botanical Council.
8. ^ Lewis WH, Smith PR (December 1979). "Poke root herbal tea poisoning". JAMA 242 (25): 2759–60. doi:10.1001/jama.242.25.2759. PMID 501875. 
9. ^ Tang W, Eisenbrand G. Chinese Drugs of Plant Origin: Chemistry, Pharmacology, and Use in Traditional and Modern Medicine . New York, NY: Springer-Verlag; 1992:765
10. ^ Suga Y, Maruyama Y, Kawanishi S, Shoji J (1978). "Studies on the constituents of phytolaccaceous plants. I. On the structures of phytolaccasaponin B, E and G from the roots of Phytolacca americana L.". Chem Pharm Bull 26: 520–5. 
11. ^ [1] Harvey Wickes Felter and John Uri Lloyd 1898. King's American Dispensatory.
12. ^ US 5252330  Method of controling zebra mussels with extract of Phytolacca dodecandra

• Elvin-Lewis, Memory P. F.; Lewis, Walter Hepworth (2003). Medical botany: plants affecting human health (2nd ed.). Chichester: John Wiley & Sons. p. 82. ISBN 0-471-62882-4. 
• "Complete Pokeweed Information" from Drugs.com professional

External links

• Germplasm Resources Information Network: Phytolacca americana
• HikeArizona.COM: Phytolacca americana
• Plants For A Future: Phytolacca americana
• Phytolacca americana in the Flora of North America
• Phytolacca americana in John Uri Lloyd's Kings American Dispensatory
• Phytolacca americana in Finley Ellingwood's The American Materia Medica, Therapeutics and Pharmacognosy.
• Felter's Materia Medica