''Frangula purshiana'' (cascara, cascara buckthorn, cascara sagrada, bearberry, and in the Chinook Jargon, chittem stick and chitticum stick; syn. ''Rhamnus purshiana'') is a species of plant in the family Rhamnaceae. It is native to western North America from southern

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

south to central

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

, and eastward to northwestern

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...

. The dried bark of cascara was used as a

laxative Laxatives, purgatives, or aperients are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation. Laxatives vary as to how they work and the side effects they may have. Certain stimulant, lubri ...

folk medicine Traditional medicine (also known as indigenous medicine or folk medicine) comprises medical aspects of traditional knowledge that developed over generations within the folk beliefs of various societies, including indigenous peoples, before the ...

by the

indigenous people Indigenous peoples are culturally distinct ethnic groups whose members are directly descended from the earliest known inhabitants of a particular geographic region and, to some extent, maintain the language and culture of those original people ...

s of the

Pacific Northwest The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Tho ...

, and later worldwide in conventional medicines until 2002.

Description

Cascara is a large shrub or small tree tall, with a trunk 20–50 centimetres (8–20 in) in diameter. The buds have no scales, unique for the northwest region. The thin bark is brownish to silver-gray with light splotching (often, in part, from

lichens A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. The leaves are simple,

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, ...

, alternate, clustered near the ends of twigs. They are oval, 5–15 cm (2–6 in) long and broad with a petiole, shiny and green on top, and a dull, paler green below; they have tiny teeth on the margins, and 10–12 pairs of pinnate veins. The leaves turn yellow in autumn. The flowers are tiny, diameter, with five greenish yellow petals, forming a cup shape. The flowers bloom in umbel-shaped clusters, on the ends of distinctive peduncles that are attached to the leaf axils. The flowering season is brief, from early to mid- spring, disappearing by early summer. The fruit is a drupe diameter, bright red at first, quickly maturing deep purple or black, and containing a yellow pulp, and two or three hard, smooth, olive-green or black

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

s. File:Rhamnus purshiana -- “Cascara” -- leaf and buds.png, Closeup of leaf and buds File:Cascara (Rhamnus purshiana) bark.JPG, Splotchy bark File:Rhamnus purshiana, Cascara -- branch with leaves, flowers and buds.JPG, Branch with prominently veined, alternate leaves, reddish twigs, and clusters of flowers at the leaf axils File:Rhamnus purshiana -- leaves and fruits.JPG, Leaves, flower, and young fruits

Distribution and habitat

Cascara is native from northern

and east to the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico ...

. It is often found along streamsides in the mixed

- coniferous forests of valleys, and in moist montane forests. Cascara is common in the understory of

bigleaf maple ''Acer macrophyllum'', the bigleaf maple or Oregon maple, is a large deciduous tree in the genus '' Acer''. It is native to western North America, mostly near the Pacific coast, from southernmost Alaska to southern California. Some stands are al ...

forest, alongside

red osier dogwood ''Cornus sericea'', the red osier or red-osier dogwood, is a species of flowering plant in the family Cornaceae, native to much of North America. It has sometimes been considered a synonym of the Asian species '' Cornus alba''. Other names inclu ...

and

red alder ''Alnus rubra'', the red alder, is a deciduous broadleaf tree native to western North America (Alaska, Yukon, British Columbia, Washington, Oregon, California, Idaho and Montana). Description Red alder is the largest species of alder in Nort ...

. In many areas, the high market demand for cascara bark has led to over-harvesting from wild trees, which may have heavily reduced cascara populations.

Ecology

It is browsed by

mule deer The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer. Unlike the related whi ...

in Oregon and

elk The elk (''Cervus canadensis''), also known as the wapiti, is one of the largest species within the deer family, Cervidae, and one of the largest terrestrial mammals in its native range of North America and Central and East Asia. The common ...

in northern Idaho, especially in the winter months. The

Olympic black bear The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bear ...

, Oregon gray fox,

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight of ...

, and

ring-tailed cat The ringtail (''Bassariscus astutus'') is a mammal of the raccoon family native to arid regions of North America. It is widely distributed and well adapted to disturbed areas. It has been legally trapped for its fur. It is listed as Least Co ...

also eat Cascara foliage. The fruit is eaten by birds, bears, raccoons, and other mammals, who distribute the undigestible seeds. Cascara creates brushy stands which provide abundant thermal and hiding cover for wildlife. Cascara is usually top-killed by fire, but may resprout from the root crown. After more severe fires, it reestablishes via off-site seed beginning the second year after the fire. It typically inhabits areas with

fire regime A fire regime is the pattern, frequency, and intensity of the bushfires and wildfires that prevail in an area over long periods of time. It is an integral part of fire ecology, and renewal for certain types of ecosystems. A fire regime describes th ...

s on 30 to 150 year intervals, although it is also found in areas with fire regimes of 500+ years. The tree is

shade tolerant In ecology, shade tolerance is a plant's ability to tolerate low light levels. The term is also used in horticulture and landscaping, although in this context its use is sometimes imprecise, especially in labeling of plants for sale in commercial ...

Toxicity

The fruit and bark contain a bitter chemical making them inedible to humans, although there are contested medicinal uses. Until 2002, cascara was the principal ingredient in commercial,

over-the-counter Over-the-counter (OTC) drugs are medicines sold directly to a consumer without a requirement for a prescription from a healthcare professional, as opposed to prescription drugs, which may be supplied only to consumers possessing a valid prescr ...

(OTC)

s in North American

pharmacies Pharmacy is the science and practice of discovering, producing, preparing, dispensing, reviewing and monitoring medications, aiming to ensure the safe, effective, and affordable use of medicines. It is a miscellaneous science as it links healt ...

until the

U.S. Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

(FDA) issued a final rule banning the use of aloe and cascara as laxative ingredients. Serious

adverse effect An adverse effect is an undesired harmful effect resulting from a medication or other intervention, such as surgery. An adverse effect may be termed a " side effect", when judged to be secondary to a main or therapeutic effect. The term compl ...

s may occur from using cascara, including dehydration, loss of electrolyte levels (such as potassium, sodium, chloride), heart rhythm irregularities, and muscle weakness. There is also concern for its potential

carcinogenicity A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive sub ...

. Laxatives should also not be used by people with Crohn's disease,

irritable bowel syndrome Irritable bowel syndrome (IBS) is a "disorder of gut-brain interaction" characterized by a group of symptoms that commonly include abdominal pain and or abdominal bloating and changes in the consistency of bowel movements. These symptoms may ...

colitis Colitis is swelling or inflammation of the large intestine ( colon). Colitis may be acute and self-limited or long-term. It broadly fits into the category of digestive diseases. In a medical context, the label ''colitis'' (without qualification ...

, hemorrhoids,

appendicitis Appendicitis is inflammation of the appendix. Symptoms commonly include right lower abdominal pain, nausea, vomiting, and decreased appetite. However, approximately 40% of people do not have these typical symptoms. Severe complications of a ru ...

, or

kidney The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blo ...

problems. Use of cascara is a safety concern for pregnant or breastfeeding women, and for children.

Dietary supplement

Cascara is sold in the United States as a dietary supplement and commonly ingested by mouth to relieve

constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...

. Although it may be safe for use over a few days, there is insufficient scientific evidence to assure its safety and effectiveness. Use of cascara may adversely affect the actions of various prescribed drugs, such as digoxin,

warfarin Warfarin, sold under the brand name Coumadin among others, is a medication that is used as an anticoagulant (blood thinner). It is commonly used to prevent blood clots such as deep vein thrombosis and pulmonary embolism, and to prevent st ...

, corticosteroids, and

diuretic A diuretic () is any substance that promotes diuresis, the increased production of urine. This includes forced diuresis. A diuretic tablet is sometimes colloquially called a water tablet. There are several categories of diuretics. All diuretics i ...

agents.

Phytochemistry

Numerous quinoid phytochemicals are present in cascara bark. The chemicals possibly contributing to a laxative effect are the

hydroxyanthracene Hydroxyanthracenes are a class of natural phenolic compounds. They can be found in '' Cassia alata'' and '' Cassia senna'' ( sennosides A, B, C and D). References Natural phenols {{aromatic-stub ...

glycosides, which include cascarosides A, B, C, and D. Cascara contains approximately 8% anthranoids by mass, of which about two-thirds are cascarosides. The hydroxyanthracene glycosides may trigger

peristalsis Peristalsis ( , ) is a radially symmetrical contraction and relaxation of muscles that propagate in a wave down a tube, in an anterograde direction. Peristalsis is progression of coordinated contraction of involuntary circular muscles, whic ...

by inhibiting the absorption of water and

electrolytes An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon di ...

in the

large intestine The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before bein ...

, which increases the volume of the

bowel The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

contents, leading to increased pressure. The hydroxyanthracene glycosides are not readily absorbed in the small intestine, but are hydrolyzed by

intestinal flora Gut microbiota, gut microbiome, or gut flora, are the microorganisms, including bacteria, archaea, fungi, and viruses that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the gut mi ...

to a form that is partly absorbed in the colon. Some of the chemical constituents present in the bark may be excreted by the kidneys. The extract from cascara bark also contains

emodin Emodin (6-methyl-1,3,8-trihydroxyanthraquinone) is a chemical compound, of the anthraquinone family, that can be isolated from rhubarb, buckthorn, and Japanese knotweed ('' Reynoutria japonica'' syn. ''Polygonum cuspidatum''). Emodin is particula ...

, which may contribute to the laxative effect.

Uses

Traditional medicine

Cascara was used in

traditional medicine Traditional medicine (also known as indigenous medicine or folk medicine) comprises medical aspects of traditional knowledge that developed over generations within the folk beliefs of various societies, including indigenous peoples, before the ...

as a laxative. The dried, aged bark of ''R. purshiana'' used by

indigenous Indigenous may refer to: *Indigenous peoples *Indigenous (ecology), presence in a region as the result of only natural processes, with no human intervention *Indigenous (band), an American blues-rock band *Indigenous (horse), a Hong Kong racehorse ...

native cultures and immigrant Euro-Americans as a laxative is similar to other

anthraquinone Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic organic compound with formula . Isomers include various quinone derivatives. The term anthraquinone however refers to the isomer, 9,10-anthraquinone (IUPAC: 9,10-dioxoan ...

-containing herbal preparations of leaves and fruits of senna, the

latex Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well. In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...

of '' Aloe vera'', and the root of the rhubarb plant. Commercially, it is called "cascara sagrada" ('sacred bark' in Spanish), while in the traditional Chinook Jargon it is known as ''"chittem bark"'' or ''"chitticum bark"''. Following its introduction to formal U.S. medicine in 1877, it replaced the berries of '' R. catharticus'' as the favored laxative. The historical interest in using cascara damaged native cascara populations during the 1900s due to overharvesting.

Preparation in folk medicine

The bark is collected in the spring or early summer, when it easily peels from the tree. Once stripped from the tree, the bark must be aged for several months, because fresh cut, dried bark causes

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteri ...

and violent

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 ...

. This drying is generally done in the shade to preserve its characteristic yellow color. This process can be quickened by simply baking the bark at a low temperature for several hours. Botanist

Julia Morton Julia Frances McHugh Morton (April 25, 1912 – September 10, 1996) was an American author and botanist. She was research professor of biology, and director of the Morton Collectanea at the University of Miami. She was elected a Fellow of the ...

suggests using a dose of 10–30

grains A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legumes ...

, dissolved in water, or 0.6–2.0 cc for fluid extract. James A. Duke suggests an effective dosage of approximately dried bark, or powdered bark.

Other uses

The fruit can also be eaten cooked or raw, but has a laxative effect. The food industry sometimes uses cascara as a flavoring agent for liquors, soft drinks, ice cream, and baked goods. Cascara honey is tasty, but slightly laxative. The wood is used by local people for posts, firewood, and turnery. It is also planted as an ornamental, to provide food and habitat for wildlife, or to prevent soil

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is dis ...

. Due to its bitter taste, cascara can be used to stop nail-biting by applying it to the fingernails.

References

External links

Flora of British Columbia: ''Rhamnus purshiana''Jepson Flora Project: ''Rhamnus purshiana''USDA Plants Profile: ''Frangula purshiana''Documents related to FDA-1978-N-0021 (Formerly 1978N-036L): Cascara OTC
{{Authority control purshiana Trees of Western Canada Trees of the Northwestern United States Trees of British Columbia Flora of California Flora of the Cascade Range Flora of the Klamath Mountains Flora of the Sierra Nevada (United States) Flora of the West Coast of the United States Natural history of the California chaparral and woodlands Natural history of the California Coast Ranges Trees of humid continental climate Trees of mild maritime climate Medicinal plants of North America Taxa named by Augustin Pyramus de Candolle Flora without expected TNC conservation status