''Ipomoea purga'' is a species of flowering plant in the genus ''

Ipomoea ''Ipomoea'' () is the largest genus in the plant family Convolvulaceae, with over 600 species. It is a large and diverse group, with common names including morning glory, water convolvulus or water spinach, sweet potato, bindweed, moonfl ...

''. It is commonly referred to as jalap and is probably also the source of the

John the Conqueror John the Conqueror, also known as High John de Conqueror, John, Jack, and many other folk variants, is a folk hero from African-American folklore. He is associated with the roots of '' Ipomoea purga'', the John the Conqueror root or John the Co ...

root.

Description

''Ipomoea purga'' is described as a vine that can reach heights of . When fresh, the root is black externally, white and milky within, and varies in size according to its age. It has heart shaped leaves and purple trumpet like flowers. ''Ipomoea purga'' is rather difficult to break down, but if triturated with cream of tartar, sugar of milk, or other hard salts, the process of pulverization is much easier, and the powder rendered much finer. When in powder form in order to ingest, the color is a pale grayish brown. ''Ipomoea purga'' is native to

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

and it is naturalized in other parts of the neotropics.

Discovery

''Ipomoea purga'' was encountered by Spanish conquistadores during the conquest of Mexico. It was introduced to Europe in 1565 as a medical herb used to treat an array of illnesses up until the 19th century when modern medical practices became the norm.

Medical uses

The root contains convolvulin, which is a powerful

cathartic In medicine, a cathartic is a substance that ''accelerates'' defecation. This is similar to a laxative, which is a substance that ''eases'' defecation, usually by softening feces. It is possible for a substance to be both a laxative and a catha ...

(see jalap). It is used to prevent

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...

, but large amounts will induce vomiting. When applied to a wound, it is said to induce purgation.

Chemical composition

''Ipomoea purga'' resin can be dissolved in either alcohol or

diethyl ether Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable li ...

. The resin that is insoluble in ether is odorless while the resin insoluble in alcohol does have an odor and is typically a brownish color. The convolvulinolic acid (C₂₈H₅₂O₁₄)that is produced in ''Ipomoea purga'' can be broken down into a sugar molecule (C₆H₁₂O₆) and a form of crystallized convolvulinolic acid (C₁₆H₃₀O₃) when diluted.

Synonyms

;Basionym *''Convolvulus purga'' Wender., Pharmac. Centralb. 1:457. 1830. ;Homotypic *''Exogonium purga'' (Wender.) Benth., Pl. Hartw. 46. 1840. ;Heterotypic *''Convolvulus officinalis'' Pelletan, J. Chim. Méd. t. 1. 1834. *''Ipomoea jalapa'' Nutt. & Cox, Journ. Am. Med. Sci. 5: 305. 1830, nom illeg. non Pursh (1813). *''Ipomoea jalapa'' Schiede & Deppe ex G. Don, Gen. Hist. 4: 271. 1838. *''Ipomoea schiedeana'' Zucc., Flora vol. 14, 802. 1831. Species:Ipomoea purga

References

{{Taxonbar, from=Q1123117 purga Flora of Mexico