How It Works
Bottom Line: Cascara is a strong laxative, and although it works, the F.D.A. warns that it is not safe to use. There is NO proof that cascara has anti-cancer activity.
Cascara is made out of the bark of the Cascara sagrada plant. It is known to stimulate the large intestine and produce a well-documented laxative effect. Cascara also causes water and electrolytes (such as sodium and potassium) to flow into the large intestine and be expelled from the body with the feces. This facilitates bowel passage but also can lead to dangerously low potassium and sodium levels if cascara is used for prolonged periods of time. Scientists have isolated a compound called aloe-emodin from cascara. In laboratory studies, this compound is able to inhibit the growth of tumor cells by halting cell division, but it is unknown if this effect would take place in the human body. Scientists have also studied whether cascara might be a carcinogen, with inconsistent results.
Purported Uses
- As a laxative to relieve constipation
Scientific evidence supports this use, but prolonged use is not recommended because it can lead to dangerous blood electrolyte imbalances. The F.D.A. warns that cascara is not safe to use as a laxative.
- To treat cancer
Laboratory studies show that one compound found in cascara, aloe-emodin, has anticancer activity, but laboratory results are often not transferable to the human body. There is no proof from clinical trials that cascara has anticancer activity.
Research Evidence
A handful of clinical trials have reported the effectiveness of cascara as a laxative for cleansing the bowel before medical procedures.
Warnings
- Long-term use or overdose of cascara can cause electrolyte imbalances, characterized by very low blood levels of potassium, sodium, and chloride. It may lead to liver injury. The F.D.A. warns that cascara is not safe to use as a laxative.
- There is a chance that cascara is a carcinogen (cancer-causing substance).
- Certain compounds in cascara can discolor the urine and interfere with urinalysis.
- This product is regulated by the F.D.A. as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
Do Not Take If
- You have intestinal obstruction or undiagnosed abdominal symptoms (cascara can worsen such conditions).
- You have inflammatory bowel disease (patients should use caution with cascara).
- You are pregnant or nursing (the safety of cascara is unknown).
- You are taking diuretics (cascara can cause excessive loss of potassium).
- You are taking digoxin (cascara may have additive cardiac effects because it can cause low blood potassium levels).
Special Point
Cascara is one of the ingredients in the
Hoxsey herbal therapy, which is promoted for cancer. There is no evidence that the Hoxsey herbal therapy is effective in treating cancer.
Scientific Name
Rhamnus Purshiana
Common Name
Cascara Sagrada, Sacred Bark
Clinical Summary
Derived from the bark of the plant. Cascara is mainly used to relieve constipation. The major constituents are cascarosides that stimulate the large intestine and produce a laxative effect. Cascara is one of the herbs incorporated in the Hoxey herbal therapy. In vitro studies suggest an active ingredient emodin may have chemopreventive effects (10). No controlled human trials are available to confirm these effects. Cascara is not indicated for long term use. Prolonged use or overdose may cause diarrhea, electrolyte imbalance and hepatitis (7). The FDA rules that cascara is not safe as a stimulant laxative.
Food Sources
Food flavoring agent
Purported uses
- Cancer treatment
- Constipation
Constituents
Anthracene glycosides:Cascarosides, aloins, chrysaloins, aloe-emodin, chrysophanol, emodin and physcion
Others: Linoleic acid, myristic acid, syringic acid, lipids, resin and tannin
(1)
Mechanism of Action
The major constituents cascarosides stimulate the large intestine and produce a well-documented laxative effect
(1) (3). Cascarosides increase intestinal motility and lead to propulsive contractions. This results in an increased water and electrolyte content in the lumen, which further facilitates bowel passage. The other constituent emodin has direct excitatory effect on circular smooth muscle cells in the large intestine
(9). Cascara's anticancer activities may arise from its emodin and aloe-emodin content. In vitro studies show that aloe-emodin induces p53 and p21 expression resulting in cell cycle arrest in the G1 phase
(8). However, more studies are needed to confirm this effect. Studies on the carcinogenic effects of cascara have produced conflicting results
(4) (5) (6) (10).
Pharmacokinetics
After ingestion, cascara glycosides pass through the small intestine unchanged. Upon reaching the large intestine, glycosides are hydrolysed and activated by local bacteria. Studies show that the dimeric aglycones are well absorbed through the intestinal wall and strongly bind to plasma proteins. Aglycones are excreted through the bile.
(9)
Warnings
Contraindications
Cascara should not be used by patients with intestinal obstruction or undiagnosed abdominal symptoms. Patients with inflammatory bowel disease should use caution with this supplement.
Anthraquinone-containing laxatives like cascara should not be used by pregnant or nursing mothers.
Adverse Reactions
Reported: Fresh cascara contains anthrones, which may cause vomiting and intestinal cramps.
Toxicity: Excessive use can cause diarrhea and weakness.
Rare: Cascara has been associated with cholestatic hepatitis.
(2) (3) (7)
Herb-Drug Interactions
Diuretics: Cascara can cause excessive loss of potassium.
Digoxin: Cascara may potentiate cardiac effects.
Lab Interactions
Decreased serum potassium.
Anthraquinones in cascara may discolor the urine and interfere with diagnostic tests.
(3)
Literature Summary and Critique
No clinical studies document the anticancer effect of cascara. In vitro studies of aloe-emodin, an active ingredient, suggest antiproliferative activities.
References
- Barnes J, et al. Herbal Medicines. Second Ed. London: Pharmaceutical Press; 2002.
- DerMarderosian A, editor. The Review of Natural Products. St. Louis: Facts and Comparisons; 1999.
- Gruenwald J, et al. PDR for Herbal medicines, Montvale (NJ): Medical Economics Company; 1998.
- Borrelli F, et al. Effect of bisacodyl and cascara on growth of aberrant crypt foci and malignant tumors in the rat colon. Life Sci 2001;69:1871-7.
- Wang H, et al. Induction of cytochromes P450 1A1 and 1B1 by emodin in human lung adenocarcinoma cell line CL5. Drug Metab Dispos 2001;29:1229-35.
- Mereto E, et al. Evaluation of the potential carcinogenic activity of Senna and Cascara glycosides for the rat colon. Cancer Lett 1996;101:79-83.
- Nadir A, et al. Cascara sagrada-induced intrahepatic cholestasis causing portal hypertension: case report and review of herbal hepatotoxicity. Am J Gastroenterol 2000;95:3634-7.
- Kuo P, et al. The antiproliferative activity of aloe-emodin is through p53-dependent and p21-dependent apoptotic pathway in human hepatoma cell lines. Life Sci 2002;71:1879-92.
- DeWitte P, et al. Bicascarosides in fluid extracts of cascara. Planta Med 1991;57:440-3.
- Koyama J, et al. Chemopreventive effects of emodin and cassiamin B in mouse skin carcinogenesis. Cancer Lett 2002;182:135-9.
