encyclopedia

Cascara Bark

Scientific Names:    

Rhamnus purshiana DC (syn. Frangula purshiana (DC) A Gray ex JC Cooper [Fam. Rhamnaceae]    
     

Forms:    

Fresh or dried bark of the stem and branches of Rhamnus purshiana.    
     

Traditional Usage:    

– Anal fissures
– Cellular Regeneration
– Cleansing
– Constipation
– Detoxifying
– Hemorrhoids
– Laxative
– Pre and Post Operative Cleansing     
     
    
Overview:    

Cascara, Rhamnus purshiana DC [Fam. Rhamnaceae], also known as Cascara Sagrada, Rhamni Purshianae cortex and Rhamnus, is native to the forests of the North American Pacific Coast, ranging from northern California to British Columbia and almost to the Alaska panhandle. The bark was traditionally used as a laxative by North American indigenous peoples. Cascara bark is now listed as a laxative in the pharmacopoeias of over 17 different countries around the world. The bark is primarily used for constipation and for conditions that require a softened stool such as hemorrhoids, anal fissures, and after rectal-anal surgery. The bark of a related Eurasian species, Rhamnus frangula, is used likewise for the same purposes. The bark is taken from the stem and branches in the spring but must be stored for at least a year or, alternatively, heat treated before using to allow anthrones in the fresh bark to oxidize, otherwise preparations will cause stomach upset. Cascara bark acts as a mild laxative that works by preventing electrolytes and water from being absorbed in the large intestine; the excess liquid softens the stool and promotes bowel contractions. Both the German and British Pharmacopoeias recommend Cascara bark for constipation and for all disorders in which defecation with a soft stool is desired, e.g. anal fissures, hemorrhoids and after rectal operations. The active glycosides are hydrolyzed in the gut into their aglycones at least in part by the action of bacterial enzymes; by influencing the water and electrolyte transport in the colon, these aglycones are responsible for the laxative action. Emodin at different concentrations has many therapeutic benefits including: anti-inflammatory at 15mg/kg; antiseptic; antispasmodic; antiulcer, cathartic; vasorelaxant and viricidal. Anthraquinones are also cytotoxic and stimulate cellular regeneration, detoxification and cleansing. Chronic use of anthraquinones-type laxatives, however, often causes pseudomelanosis coli and should be avoided.    
   
     
Active Ingredients:    

Cascara bark contains: 8-10% of a complex mixture of anthraquinone glycosides of which 60-70% are cascarosides A, B, C, D, E, and F, 10-30% are aloins A and B with chrysaloins A and B and 10-20% are anthroquinone O-glycosides and free anthraquinones including: aloe-emodin, frangula emodin, iso-emodin, chrysophanol and physcion. The bark also contains resins, tannins and lipids. Cascarosides A and B are alooin O- and C-glycosides) and cascarosides C and D are deoxyaloin O- and C-glycosides. The bark also contains barbaloin and O-glycosides of emodin (e.g. frangulin), emosin oxanthrone and palmidin A, B, and C (also found in Rhubarb Root). The bark also contains linoleic acid, myristic acid and syringic acid.    
     
    
Suggested Amount:    

The daily dosage with tea is 1-2g of cut or powdered aged bark yielding 20-30mg hydroxyanthracene derivates, calculated as cascaroside. To make a tea: Pour boiling water over 1-2 g of finely chopped Cascara bark, steep 10 minutes and then strain. 1 Teaspoon = 2.5 g. Average daily dose is 20-160 mg hydroxyanthracene derivatives. The bark takes about 6 to 8 hours to work after ingestion and should not be used for more than a few days at a time unless otherwise prescribed. Only aged drug should be used. Anthrones found in the fresh bark will irritate the stomach and may cause vomiting, colic, and bloody diarrhea.    
     
     
Drug Interactions:    

In large dosages, the anthraquinones-type laxative compounds may increase the action of other laxatives and should not be taken at the same time. With chronic use/abuse, a potassium deficiency may develop that may potentiate the effects of cardiotonic glycosides.    
     
       
Contraindications:    

Laxatives are contraindicated in the case of impacted bowel (serious bowel obstruction) or ileus of any origin (danger of intestinal rupture). Stimulant laxatives are also not recommended for the treatment of chronic constipation. Do not use during pregnancy and lactation, or if you have occlusion of the intestines, appendicitis, colitis or Crohn's disease.    
     
     
Side Effects:    

Cascara Bark should not be taken for long periods of time. Excessive use will result in loss of electrolytes, especially potassium, and may cause muscular weakness, constipation, and pigment deposits in the mucous membranes of the intestines (melanosis coli). A recent study suggested that pseudomelanosis coli is associated with an increased colorectal cancer risk.    
     
       
References:    

Blumenthal M, Goldberg A, Brinckmann J 2000. Herbal Medicine: Expanded Commission E Monographs. Copyright American Botanical Council. Publ. by Integrative Medicine Communications, 1029 Chestnut Street, Newton, MA 02464. Pp. 47-51.
 
Bradley PR (ed). 1992. Cascara Bark. In British Herbal Compendium. Volume 1. A Handbook of Scientific Information on Widely Used Plant Drugs. British Herbal Medicine Association, Bournemouth, Dorset, pp. 52-54.
 
Newall CA, Anderson LA, and Phillipson JD. 1996. Cascara. In Herbal Medicines. A Guide for Health Care Professionals. The Pharmaceutical Press, London, pp. 62.
 
Pojar, J. and A. MacKinnon (Eds.) 1994. Plants of Coastal British Columbia, including Washington, Oregon and Alaska. Publ. by Lone Pine Publishing, 202A-1110 Seymour Street, Vancouver, B.C., Canada, V6B 3N3. Pp. 90-91.
 
Wichtl M and NG Bisset (Eds). 1994. Rhamni purshiani cortex – Cascara bark (English translation by Norman Grainger Bisset). In Herbal Drugs and Phytopharmaceuticals. CRC Press, Stuttgart, pp. 412-414.