Lactuca virosa

Wild lettuce
Wild lettuce (Lactuca virosa)
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Tribe: Cichorieae
Genus: Lactuca
Species: L. virosa
Binomial name
Lactuca virosa
L.

Lactuca virosa is a plant in the Lactuca (lettuce) genus, ingested often for its mild psychotropic (specifically hypnotic or sedative) effects which are often described as being similar to those of opium.[1] It is related to common lettuce (L. sativa), and is often called wild lettuce, bitter lettuce, laitue vireuse, opium lettuce, poisonous lettuce, tall lettuce, great lettuce[2] or rakutu-karyumu-so.

It can be found locally in the south east and east of England. In the rest of Great Britain it is very rare, and in Ireland it is absent. It is also found in the Punjab Region of Pakistan India and Australia where it grows in the wild.

In North America, it has been documented as introduced in California, Alabama, Iowa, and Washington, DC, and grows wild in other parts of the continent.[3]

Description

It is biennial, similar to prickly lettuce Lactuca serriola but taller - it can grow to 200 cm. It is also stouter, the stem and leaves are more purple flushed, the leaves are less divided, but more spreading.

The achene is purple black, without bristles at the tip. The pappus is the same as Lactuca serriola.

It flowers from July until September.[4]

History

L. virosa was used in the 19th century by physicians when opium could not be obtained. It was studied extensively by the Council of the Pharmaceutical Society of Great Britain in 1911. They discovered two chemicals responsible for the properties of L. virosa; lactucopicrin and lactucin. In the United States, the plant experienced a resurgence in popularity in the 1970s. Today the plant is un-scheduled by the Food and Drug Administration (FDA), meaning it is legal to grow, purchase and own without prescription or license.

Pharmacology

A latex which is called lactucarium can be derived from the extract of the stem secretions of Lactuca virosa. Oils and extracts can also be produced from L. virosa. These oils and extracts have sedative properties in rodents.[1] They may be added to tea to help induce sleep. While its use as a galactagogue (a substance that increases breast milk) has been reported, the sedative effects on the baby would strongly argue against its use for this purpose. Many add the greens to salads, though the leaves of L. virosa are more bitter than other salad greens. Smoking involves either dried leaves or a sticky precipitate extracted from the leaves. Beverages can be prepared by soaking the leaves in alcohol.

The plant contains flavonoids, coumarins, and N-methyl-β-phenethylamine.[5] A variety of other chemical compounds have been isolated from L. virosa. One of the compounds, lactucin, is an adenosine receptor agonist in vitro,[1] while another, lactucopicrin, has been shown to act as an acetylcholinesterase inhibitor in vitro.[6]

Lactuca virosa

References

  1. ↑ 1.0 1.1 1.2 Wesołowska, A.; Nikiforuk, A.; Michalska, K.; Kisiel, W.; Chojnacka-Wójcik, E. (2006). "Analgesic and sedative activities of lactucin and some lactucin-like guaianolides in mice". Journal of Ethnopharmacology 107 (2): 254–8. doi:10.1016/j.jep.2006.03.003. PMID 16621374.
  2. ↑ "BSBI List 2007" (xls). Botanical Society of Britain and Ireland. Retrieved 2014-10-17.
  3. ↑ efloras.org entry in Flora of North America
  4. ↑ Rose, Francis (1981). The Wild Flower Key. Frederick Warne & Co. pp. 391–392. ISBN 0-7232-2419-6.
  5. ↑ Holistic Online herb information: Wild Lettuce
  6. ↑ Rollinger, JM; Mocka, P; Zidorn, C; Ellmerer, EP; Langer, T; Stuppner, H (2005). "Application of the in combo screening approach for the discovery of non-alkaloid acetylcholinesterase inhibitors from Cichorium intybus". Current drug discovery technologies 2 (3): 185–93. doi:10.2174/1570163054866855. PMID 16472227.

General references

  1. Blanchan, Neltje (2005). Wild Flowers Worth Knowing. Project Gutenberg Literary Archive Foundation.

External links

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