Polygala senega L. (Seneca Snakeroot)

The genus name Polygala means "much milk," and has also been interpreted as a reference by the ancient Greek physician to the Roman Army, Dioscorides, to some low shrub reputed to promote milk secretion. "Senega" is derived from the Seneca tribe of North American Indians, who used the plant as a remedy for snake-bites.

English Common Names

Seneca snakeroot, Seneca-snakeroot, Senega root, Senega snakeroot, rattlesnake root, mountain flax, white snakeroot (a name more generally applied to Eupatorium rugosum).

Several unrelated species have the common name "snakeroot," and are sometimes confused with seneca snakeroot.

French Common Names

Polygala sénéca, polygala de Virginie.

Morphology

Seneca snakeroot is a perennial herb. Several erect stems, 10-50 cm tall, arise from the branched root, and bear alternate, lance-shaped leaves. The lowest leaves are small and scalelike.

Spikes of roundish, small, white (frequently tinged with green) flowers appear in June and early July. The short capsules ripen in July and August, and have two blackish, hairy seeds with long white appendages (arillodes). The dandelion-like root is slender, conical, with an enlarged crown, tortuous, yellowish-grey or brownish on the outside and cream-colored internally, with a sweetish odour reminiscent of wintergreen, and a strongly acrid taste.

In commerce, two root types are often recognized. The more desirable Northern or Manitoba Seneca snakeroot has larger roots (up to 15 cm long and 12 mm thick), which are dark brown and purplish near the crown. It is collected in Manitoba, Saskatchewan and Minnesota. Southern or small Seneca snakeroot, which comes from South Carolina and Georgia, has roots up to 8 cm long and 7 mm thick, which are brownish-yellow.

Classification and Geography

Polygala senega has a broad range in Canada, extending from the St. John River system of New Brunswick, south-western Quebec, Ontario, Manitoba and Saskatchewan to Alberta. It also occurs throughout much of the eastern and Midwestern United States south to Georgia.

Distribution Map

Description of this image follows.

Description of the above image

Polygala senega in Canada, extends from New Brunswick, south-western Quebec, Ontario, Manitoba and Saskatchewan to Alberta. It is also found in eastern and Midwestern United States south to Georgia.

Ecology

Habitats include prairies, savannas and periodically dry, often somewhat open woods. Light availability varies from open sky to partial shade. Soils occupied are often rocky, and the plants have been recorded in quite basic soils (the pH as high as 9).

The breeding system of Seneca snakeroot requires study, but related species are pollinated by bees. The seed appendages may be utilized as food by ants which disperse the seed over short distances. Dispersal over longer distances is probably by birds.

Medicinal Uses

Seneca snakeroot was utilized by the Seneca Indians in treatment of rattlesnake bite. Canadian botanist Frère Marie-Victorin suggested that the resemblance of the knotty root crown to a rattlesnake's tail may have contributed to its use by the Seneca as an antidote.

Its use, however, was not confined to the Seneca, for it was considered to have several medicinal properties, especially in relation to respiratory ailments, among other tribes including Ojibwa, Huron, Menomini and Iroquois. Walpole Island Ojibwa of southern Ontario used the root for headache, nasal congestion and stomach ache. It was utilized as a general cure by the Ojibwa Indians and carried by them on their journeys for general health and safety.

Seneca snakeroot was sent to Europe in the early 1700s and held a regular place in European drug stores during the 1800s for use in treatment of pneumonia.

The root is ground into powder and used in various patent medicines, particularly in cough medicines, as a stimulant expectorant. It is present in some prescription drugs used in the treatment of bronchitis and asthma. Seneca snakeroot is also used in veterinary medicine. Aside from its effects on the respiratory system, it promotes perspiration and urination.

Toxicity

The root is a severe and serious irritant when too much is consumed. It can cause nausea, dizziness, diarrhea and violent vomiting.

Chemistry

The active root (pharmaceutically referred to as Senegae Radix) constituents are triterpinoid saponins (notably senegin). Also recorded are phenolic acids, polygalitol (a sorbitol derivative), methyl salicylate, and sterols.

Non-medicinal Uses

Description of this image follows.
Polygala senega
(seneca snakeroot)

Seneca snakeroot is grown to a minor extent as a garden ornamental.

Agricultural and Commercial Aspects

Seneca snakeroot was once grown to a limited extent in parts of Europe, and is still cultivated in Japan, India and Brazil. Up until the early 1960s Canada was the chief supplier of Seneca snakeroot with exports worth several hundred thousand dollars a year.

Most of the exported material originated from plants collected from the wild in Saskatchewan and Manitoba. There has been a relative decline in its value as a Canadian export. Seneca snakeroot is used in about a dozen drug products in Canada.

Other species of Polygala are sometimes used to adulterate Seneca snakeroot. Polygala tenuifolia Wild., Japanese seneca, from India and Japan, is the most frequently encountered adulterant.

Early experimental work in North America suggested that Seneca snakeroot can be grown in soil suitable for ordinary field crops, and without shade. The plants are set 40 cm apart in rows of at least the same width. The seeds have a reputation as difficult to germinate. Seedlings may be protected with straw during the first winter. About 4 years are required to produce roots of marketable size.

Although little, if at all cultivated in Canada, Seneca snakeroot is still gathered from the wild, especially by indigenous people of Manitoba and Saskatchewan, for sale to commercial pharmaceutical companies. Three quarters of the world's wild supply originates from Manitoba's Interlake District -- the land about Lakes Winnipeg, Winnipegosis, and Manitoba.

Wild plants are sufficiently plentiful that the wild resource can continue to be harvested, but since collecting mature roots sacrifices the plant, cultivation is a potentially desirable alternative. Seneca snakeroot is under consideration in several provinces as a new or alternative crop, especially to enhance its economic value to indigenous people. The most frequent admixture involves the North American ginseng (Panax quinquefolius).

The greatest current interest in seneca snakeroot is in Japan, where it is cultivated on a modest scale. Japanese scientists have recently reported on various experiments with cultivation, and they have also conducted the most recent and comprehensive work on chemical composition of the saponins. In 1993, 72 farmers produced about 10 tonnes of commercial root in Japan, suggesting that there is appreciable potential for the cultivation of seneca snakeroot in Canada.

Myths, Legends, Tales, Folklore, and Interesting Facts

  • In respect to ancient religious custom that required some fruits of the forest to be left for the gods, Manitoba Indians experienced in collecting Seneca root leave a portion of the root intact to permit re-growth.
  • The floral essence of Seneca snakeroot is thought to stimulate old memories; and also to reduce quarrelling and showing off.
  • The Cree and the Chippewa Indians believed that Seneca snakeroot had the power to protect one on long journeys.
  • Methyl salicylate in the root of Polygala senega appears to contribute to its strange characteristic of smelling and tasting sweet at first and then sour and acid.

Selected References

  • Briggs, C.J. 1988. Senega snakeroot -- a traditional Canadian herbal medicine. Can. Pharm. J. 121: 199-201.

  • Gillett, J.M. 1968. The milkworts of Canada. Canada Dept. of Agriculture, Research Branch Monograph 5. 24 pp.

  • Harris, G.H. 1891. Root foods of Seneca Indians. Proc. Rochester Acad. Sci. 1: 106-115.

  • Hayashi, S., and Kameoka, H. 1995. Volatile compounds of Polygala senega L. var. latifolia Torrey et Gray roots. Flavour Fragrance J. 10: 273-280.

  • Johnson, K.L. 1984. Whorled milkwort (Polygala verticillata) and its common relatives Seneca snakeroot and gaywings. Bull. Manit. Nat. Soc. 8(1): 10.

  • Kawatani, T., and Ono, T. 1968. Effect of light intensity on the growth and root yield of Polygala senega L. var. latifolia Torr. et Gray. Eisei Shikenjo Hokoku 86: 105-107. [In Japanese.]

  • Miller, N.G. 1971. The Polygalaceae in the southeastern United States. J. Arnold Arbor. 52: 267-284.

  • Moes, A. 1966. A parallel study of the chemical composition of Polygala senega and of "Securidaca longepedunculata" Fres. var. parvifolia, a Congolese polygalacea. J. Pharm. Belg. 21: 347-362. [In French.]

  • Pelletier, S.W., and Nakamura, S. 1967. A prosapogenin from Polygala senega and Polygala tenuifolia. Tetrahedron Lett. 52: 5303-5306.

  • Saitoh, H., Miyase, T., and Ueno, A. 1993. Senegoses A-E, oligosaccharide multi-esters from Polygala senega var. latifolia Torr. et Gray. Chem. Pharm. Bull. (Tokyo) 41: 1127-1131.

  • Saitoh, H., Miyase, T., and Ueno, A. 1993. Senegoses F-I, oligosaccharide multi-esters from the roots of Polygala senega var. latifolia Torr. et Gray. Chem. Pharm. Bull. (Tokyo) 41: 2125-2128.

  • Saitoh, H., Miyase, T., Ueno, A., Atarashi, K., and Saiki, Y. 1994. Senegoses J-O, oligosaccharide multi-esters from the roots of Polygala senega L. Chem. Pharm. Bull. (Tokyo) 42: 641-645.

  • Shoji, J., and Tsukitani, Y. 1972. On the structure of senegin - 3 of Senegae radix. Chem. Pharm. Bull. (Tokyo) 20: 424-426.

  • Takeda, O., Azuma, S., Ikeda, M., Mizukami, H., Ikenaga, T., and Ohashi, H. 1986. Cultivation of Polygala senega var. latifolia: I. Effects of seeding density and heavy manuring and dense planting cultivation on plant growth, root yield and senegin content. Shoyakugaku Zasshi 40: 103-107. [In Japanese.]

  • Takeda, O., Azuma, S., Ikeda, M., Mizukami, H., Ikenaga, T., and Ohashi, H. 1987. Studies on the cultivation of Polygala senega var. latifolia: III. Effect of cultivation temperature on the growth, root yield and senegin content. Shoyakugaku Zasshi 41: 121-124. [In Japanese.]

  • Takeda, O., Azuma, S., Mizukami, H., Ikenaga, T., and Ohashi, H. 1986. Cultivation of Polygala senega var. latifolia: II. Effect of soil moisture content on the growth and senegin content. Shoyakugaku Zasshi 40: 434-437. [In Japanese.]

  • Takiura, K., Yamamoto, M., Murata, H., Takai, H., and Honda, S. 1974. Studies on oligosaccharides. XIII. Oligosaccharides in Polygala senega and structures of glycosyl-1,5-anhydro-D-glucitols]. Yakugaku Zasshi 94: 998-1003. [In Japanese.]

  • Yoshikawa, M., Murakami,T., Ueno,T., Kadoya, M., Matsuda, H., Yamahara, J., and Murakami, N. 1995. E-senegasaponins A and B, Z-senegasaponins A and B, Z-senegins II and III, new type inhibitors of ethanol absorption in rats from Senegae Radix, the roots of Polygala senega L. var. latifolia Torrey et Gray. Chem. Pharm. Bull. (Tokyo) 43: 350-352.