Cascara Sagrada Bark Standardized Extract
Also known as: Cascara sagrada, bitter bark, sacred bark, buckthorn, Rhamnus purshiana
Overview
Cascara sagrada bark, derived from the tree *Rhamnus purshiana*, is a traditional herbal laxative. It contains anthraquinone glycosides, which are the active compounds responsible for its cathartic effects. Primarily used for short-term relief of occasional constipation, it works by stimulating bowel movements and promoting colon emptying. Extracts are often standardized for anthraquinone content to ensure consistent potency. However, research on cascara sagrada is limited and dated, with a lack of modern, high-quality randomized controlled trials. The FDA classified cascara-containing laxatives as not generally recognized as safe and effective (GRAS/GRAE) for over-the-counter use in 2002 due to insufficient safety data, highlighting significant concerns regarding its long-term safety and efficacy.
Benefits
The primary, evidence-based benefit of cascara sagrada is its effectiveness as a stimulant laxative for relieving occasional constipation. This effect is attributed to its anthraquinone glycosides, which increase intestinal motility and fluid secretion. Typical doses around 300 mg of dried extract once daily are used for this purpose, with effects generally observed within hours to a day. However, there is a notable absence of robust clinical trials with adequate sample sizes and controls that quantify its effect sizes or clinical significance using modern methodologies. While some unsubstantiated claims suggest potential antiparasitic effects, these lack rigorous scientific evidence. Due to safety concerns, its use should not exceed 6 days.
How it works
The anthraquinone glycosides in cascara sagrada are metabolized by gut bacteria into active aglycones. These aglycones primarily act on the large intestine, where they stimulate colonic peristalsis (muscle contractions) and inhibit water absorption from the gut. This dual action leads to softer stools and an increase in bowel movements, promoting evacuation. The extract essentially irritates the colonic mucosa and increases fluid secretion, facilitating the laxative effect. The oral bioavailability and subsequent effects of the active compounds can vary between individuals, as they depend on the efficiency of gut microbial metabolism.
Side effects
Cascara sagrada is considered unsafe for long-term use due to significant risks, including electrolyte imbalance, dehydration, and potential liver toxicity. Common side effects, affecting more than 5% of users, include abdominal cramping, discomfort, and diarrhea. Less common effects (1-5%) include melanosis coli, a benign pigmentation of the colon mucosa. Rare but serious adverse effects (<1%) encompass herb-induced liver injury (hepatotoxicity), intrahepatic cholestasis, and portal hypertension, which are likely linked to anthracene glycosides or contaminants. There is also a documented risk of mycotoxin (aflatoxin) contamination in raw bark material, necessitating stringent quality control. Contraindications include use in children under 10, pregnancy, lactation, and individuals with inflammatory bowel diseases such as ulcerative colitis or Crohn’s disease. While no well-documented drug interactions exist, caution is advised due to the potential for electrolyte disturbances. Liver injury cases are typically reversible upon discontinuation, emphasizing the need for careful monitoring and short-term use.
Dosage
For constipation relief, the minimum effective dose of cascara sagrada is approximately 300 mg of dried bark extract taken once daily. The typical dosing range is 100–300 mg of dried extract or 1 gram of the bark itself. Fluid extracts are generally dosed at 2–6 mL. However, a maximum safe dose and duration have not been definitively established, and its use is strongly recommended to be limited to no more than 6 consecutive days due to significant safety concerns. It should be strictly avoided during pregnancy and lactation. No specific cofactor requirements have been identified, and the absorption of its active compounds is dependent on individual gut microbiota. Formulations often include spray-dried extracts suitable for immediate-release tablets, with quality control ensured by validated HPLC methods.
FAQs
Is cascara sagrada safe for long-term use?
No, prolonged use of cascara sagrada is unsafe and can lead to serious adverse effects, including liver injury, electrolyte imbalances, and laxative dependency. Its use should be limited to short periods.
How quickly does cascara sagrada work?
Cascara sagrada typically begins to exert its laxative effects within a few hours to one day after oral administration, promoting bowel movements and relieving constipation.
Can cascara sagrada be used during pregnancy?
No, cascara sagrada is contraindicated during pregnancy due to potential emmenagogue and abortifacient effects, posing risks to both the mother and the fetus.
Does cascara sagrada cause dependency?
Yes, chronic or prolonged use of cascara sagrada can lead to laxative dependency, where the bowel becomes reliant on the stimulant to function, potentially causing colonic dysfunction.
Are there quality concerns with cascara sagrada products?
Yes, there is a known risk of mycotoxin (aflatoxin) contamination in raw cascara bark. Therefore, stringent quality control and sourcing from reputable manufacturers are crucial to ensure product safety.
Research Sources
- https://ri.conicet.gov.ar/bitstream/handle/11336/12018/CONICET_Digital_Nro.15173.pdf?sequence=1&isAllowed=y – This pharmaceutical formulation study focused on developing spray-dried cascara extract tablets that meet pharmacopeial standards. It validated an HPLC method for quantifying the extract, providing useful insights for product formulation and quality control, though it did not include clinical efficacy or safety data.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8281430/ – This systematic review and meta-analysis identified cascara sagrada as a cause of reversible herb-induced liver injury. Based on multiple case reports and series, it highlighted the hepatotoxic potential of the herb, confirming significant safety concerns despite the lack of randomized controlled trials.
- https://consensus.app/questions/cascara-sagrada-safety-studies/ – This narrative review of safety data documented various adverse effects associated with cascara sagrada, including liver toxicity and risks of mycotoxin contamination. It emphasized the importance of short-term use only and supported existing regulatory restrictions due to safety concerns, primarily drawing from observational data.
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