Frangula purshiana (DC.) A. Gray - syn.Rhamnus purshianus DC.; Rhamnus purshiana (DC.) Cooper - Rhamnaceae
cascara buckthorn, cascara sagrada, Amerikanischer Faulbaum, Cascara
Tree up to 10m high, native to western North America.
„The dried bark of cascara has been used for centuries as an herbal laxative – first by Native Americans in the Pacific Northwest, and then later by European/U.S. colonizers.“ https://en.wikipedia.org/wiki/Rhamnus_purshiana
„A tree, 4-10m high, with reddish-brown bark and hairy twigs. Leaves petiolate, elliptical, acuminate, serrulate, or sometimes entire, with 10-15 pairs of veins, dull green upper surface and pubescent underside. Inflorescence an axillary umbellate cyme of small greenish flowers. Fruit a turbinate, purplish-black drupe, about 8mm long, composed of 3 indehiscent cocci.
The fresh bark contains free anthrones and must be dried for at least 1 year or artificially aged by heat or aeration before therapeutic use.
Contains not less than 8.0% hydroxyanthracene glycosides of which not less than 60% consists of cascarosides, both calculated as cascaroside A. Quantitative analysis is performed by spectrophotometry at 515nm. A high performance liquid chromatography method for the quantitative analysis of cascarosides has been reported. The active constituents are hydroxyanthracene glycosides (6-9%). Of these, 70-90% are C-10 glycosides, with the 8 -O-glycosides, aloins A and B, and 11-desoxyaloins A and B (chrysaloins A and B) accounting for 10-30%. The diastereoisomeric pairs, cascarosides A and B and cascarosides C and D and cascarosides E and F constitute 60-70% of the total O-glycosides. Other major hydroxyanthracene glycosides (10-20%) include the hydroxyanthraquinones, chrysophanol-8 -O-glucoside and aloe-emodin-8 -O-glucoside.“
[Cortex Rhamni Purshianae, WHO Monographs on Selected Medicinal Plants - Volume 2, 2004] http://apps.who.int/medicinedocs/en/d/Js4927e/25.html#Js4927e.25
„Parts used: Dried trunk and stem bark (Rhamni purshiani cortex). Fresh bark tends to cause nausea and griping, so it is stored for one year (or artificially aged) before use. Therapeutic category: Stimulant laxative. Active ingredients: The dry bark contains 6-9% hydroxyanthraquinone glycosides, the bulk of which is made up of O-glycosides of aloeemodin, chrysophanol and emodin or C-glycosides, so-called cascarosides A,B,C, and D; also aloin A,B.“
[Medicinal Plants of the World. Ben-Erik Van Wyk and Michael Wink, Pretoria 2004, 269]