Frangula purshiana
Frangula purshiana
The cascara sagrada (Frangula purshiana (DC.) A.Gray ex J.G.Cooper) is a shrub species belonging to the Rhamnaceae family.
Systematics –
From a systematic point of view it belongs to:
Eukaryota Domain,
Kingdom Plantae,
Magnoliophyta Division,
Magnoliopsida class,
Rosales Order,
Rhamnaceae family,
Genus Frangula,
F. purshiana species.
The terms are synonymous:
– Cardiolepis obtusa Raf .;
– Frangula anonifolia (Greene) Grubov;
– Rhamnus annonifolia Greene;
– Rhamnus purshiana DC.
Etymology –
The term Frangula comes from frángo to break: for its brittle wood.
The specific Purshian epithet of the species is in honor of the American explorer and botanist of German origin Frederick (Friedrich) Traugott Pursh (1774-1820) who collected plants in the United States and Canada and wrote Flora Americae Septentrionalis.
Geographic Distribution and Habitat –
Frangula purshiana is a plant native to western North America; present from southern British Columbia to central California and eastward to northwestern Montana but can also be found on the Pacific coast of Chile. It is cultivated for medicinal purposes in Europe and Kenya.
Its habitat is that of the valleys and sides of canyons, usually in coniferous forests, forest edges, deciduous forests, river banks, coastal scrub of sage, at altitudes up to 2,000 meters.
Description –
Frangula purshiana is a large shrub or small tree 4.5–10 meters high, with a trunk of 20–50 cm in diameter.
The outer bark is brownish to silver gray in color with light patches (often, in part, due to lichen) and the inner surface of the bark is smooth and yellowish (turning dark brown with age and / or exposure to light solar).
The leaves are simple, deciduous, alternate, grouped near the ends of the twigs. They are oval, 5–15 cm long and 2–5 cm broad, with a 0.6–2 cm petiole; they are shiny and green on top and dull green and paler below; they also have tiny teeth on the margins and pinnate veins.
The flowers are tiny, 4–5 mm in diameter, with five greenish yellow petals forming a cup. The flowers bloom in umbrella-shaped clusters, at the ends of characteristic peduncles attached to the axil of the leaves.
The flowering season is short and runs from early to mid-spring, ending in early summer.
The fruit is a 6-10 mm diameter drupe, initially bright red, deep purple or black in color, rapidly ripening, containing a yellow flesh and two or three hard, smooth, olive green or black seeds.
Cultivation –
Frangula purshiana is a plant that grows spontaneously especially along the banks of streams in the mixed deciduous and coniferous forests of the valleys and in humid montane forests.
In many areas, the high market demand for bark has led to an over-harvesting of wild trees, which may have greatly reduced natural populations.
It is a plant that plays an important ecological role in its range as it is a food source for mule deer in Oregon and elk in northern Idaho, especially in the winter months. The Olympic black bear, Oregon gray fox, raccoon, and ring-tailed cat also eat the foliage of this plant.
The fruit is also eaten by birds, bears, raccoons and other mammals and creates bushy stands that provide abundant heat cover and shelter for wildlife.
It is a plant that is also cultivated and which, in the event of a fire, can sprout from the crown of the root. After more severe fires, it re-establishes itself via off-site seed starting the second year after the fire. It typically inhabits areas with fire regimes at intervals of 30 to 150 years, although it is also found in areas with fire regimes of over 500 years.
It is a moderately cold hardy plant, able to tolerate temperatures down to around -15 ° C when fully dormant.
It grows in any reasonably fertile soil, in a sunny location or in partial shade. However, the plants are very shade tolerant.
This species is grown as a medicinal plant in North America.
Propagation occurs by seed which is best sown in autumn in a cold seedbed.
Stored seed requires 1 to 2 months of cold stratification at around 5 ° C and should be sown as early as possible at the start of the year in a cold greenhouse or outdoor seedbed.
The small seedlings are then placed in single pots, grown in a cold greenhouse and transplanted in late spring or early summer of the following year.
It can also be propagated by cutting wood grown in the current year, in autumn.
Customs and Traditions –
The cascara sagrada is a plant native to North America, in particular from California; the common name “cascara sagrada” means sacred bark, derives from a legend according to which the ark of Noah was built with the bark.
Frangula purshiana was used in traditional medicine as a laxative. The dried and aged bark was used by indigenous peoples and Euro-American immigrants as a laxative and similar to other herbal preparations containing anthraquinone.
Unfortunately, the historical interest in the use of cascara damaged the native populations during the 1900s due to excessive harvesting.
The bark is harvested in spring or early summer, when it easily detaches from the tree. Once plucked from the tree, the bark must be cured for many months because the freshly cut, dried bark causes vomiting and violent diarrhea. This drying generally takes place in the shade to preserve its characteristic yellow color. This process can be accelerated by simply cooking the bark at a low temperature for several hours.
In her book, Major Medicinal Plants, Dr. Julia Morton suggested using a dosage of 10–30 grains, dissolved in water, or 0.6–2 cc for the fluid extract.
James A. Duke has suggested an effective dosage of about 1-3 grams (15 to 46 grams) of dried bark, or 1 to 2.5 grams (15 to 39 grams) of powdered bark.
Among other uses, it should be remembered that the fruit can also be eaten cooked or raw, but it has a laxative effect. The food industry sometimes uses cascara as a flavoring agent for liqueurs, soft drinks, ice cream and baked goods.
Cascara honey is tasty, but slightly laxative. The wood is used by the local population for poles, firewood and turning. It is also planted as an ornamental, to provide food and habitat for wildlife, or to prevent soil erosion.
Due to its bitter taste, cascara can be used to stop nail biting by applying it to the nails.
However, it should be remembered that given the composition of the active ingredients, the preparations based on Cascara sagrada must be used with extreme caution: they should not be administered during pregnancy, breastfeeding, in case of difficult and painful menstruation and in patients with an intestinal obstruction. Finally, fresh fruits, if consumed in excess, can cause bouts of vomiting and diarrhea.
Anthraquinone derivatives (cascarosides, aloins, etc.) are extracted from the bark of the trunk and branches. Chemicals that can contribute to a laxative effect are hydroxyanthracenic glycosides, which include cascarosides A, B, C, and D.
Frangula purshiana contains about 8% by mass of anthranoids, of which about two thirds are cascarosides. Hydroxyanthracenic glycosides can trigger peristalsis by inhibiting the absorption of water and electrolytes in the large intestine, which increases the volume of intestinal contents, leading to an increase in blood pressure.
Hydroxyanthracene glycosides are not readily absorbed in the small intestine, but are hydrolyzed by the intestinal flora into a form that is partially absorbed in the colon.
Some of the chemical constituents present in the cortex can be excreted by the kidneys. The cascara bark extract also contains emodin, which may contribute to the laxative effect.
Preparation Method –
Frangula purshiana uses the bark which, after being dried, is used as a laxative.
The parts used is exclusively the root of the trunk and branches dried for at least 1-2 years.
Cascara bark has an intensely bitter flavor that will linger in the mouth for hours, overpowering the taste buds.
Cascara-based preparations are:
– Infusion: pour one liter of boiling water into a glass or porcelain container containing approximately 10-12 g of dried and coarsely chopped Cascara Sagrada bark, leave to infuse for fifteen minutes, then strain and, if necessary, filter. If you take one to three cups during the day, if the taste is too unpleasant, sweeten with a little honey to taste.
– Powder: crush the desired amount of dried and ground bark in a mortar until a very fine powder is obtained (store in a tightly closed glass container away from moisture). The dose varies according to the desired action: 0.2-0.3 g 3 times a day, or from four to eight g per day as appropriate. The powder is taken in a host, or mixed with honey or jam.
– Tincture: macerate 30 g of dried and coarsely chopped bark in 150 ml of alcohol at 70 °, after 10-12 days of maceration, strain, filter and store in a dark glass bottle fitted with a dropper. The recommended dose is half to a tablespoon a day diluted in a little warm sugared water or at room temperature.
Guido Bissanti
Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.
Warning: Pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not represent in any way a medical prescription; therefore no responsibility is taken for their use for curative, aesthetic or food purposes.