Herbs (Global Traditional) · Native American
Rhamnus purshiana (Cascara Sagrada)
Moderate Evidencebotanical
Hermetica Superfood Encyclopedia
Cascara sagrada (Rhamnus purshiana) is a traditional Native American laxative containing anthraquinone glycosides that stimulate colon contractions. The bark's compounds cascarosides A and B increase intestinal motility by inhibiting stationary contractions while promoting propulsive movements.
Cascara sagrada is the dried bark of Rhamnus purshiana (Frangula purshiana), a deciduous shrub native to the Pacific Northwest of North America. The bark must be harvested and aged for at least one year or artificially processed through heat or aeration before therapeutic use, as fresh bark contains free anthrones requiring processing for safety.
The research dossier does not contain specific human clinical trials, randomized controlled trials, or meta-analyses evaluating cascara sagrada's efficacy. The available sources describe traditional use and pharmacological mechanisms but lack the clinical trial data and PMIDs necessary for evidence-based assessment.
The research does not specify clinically studied dosage ranges or standardization protocols for cascara sagrada preparations. Historical pharmaceutical preparations like 'Elixir Purgans' are mentioned without quantified dosing information. Consult a healthcare provider before starting any new supplement.
Cascara sagrada bark is not consumed as a food source and therefore lacks a conventional macronutrient profile (negligible protein, fat, and carbohydrate contribution at therapeutic doses). The primary bioactive compounds are anthraquinone glycosides (hydroxyanthracene derivatives), comprising approximately 6–9% of dried bark by weight. Key compounds include: • Cascarosides A, B, C, and D (collectively ~60–70% of total anthraquinone content; approximately 4–6% of dried bark), which are C-glycosides of barbaloin and chrysaloin stereoisomers — these are the principal laxative agents. • Emodin (approx. 0.1–0.3% of dried bark), a free aglycone anthraquinone with anti-inflammatory and antimicrobial properties. • Aloe-emodin (trace to ~0.2%), another free anthraquinone aglycone. • Chrysophanol (trace amounts). • Barbaloin/aloin (present as both free and glycosylated forms). • Frangulin and frangula-emodin (minor constituents). The cascarosides are prodrugs — they pass through the small intestine largely intact due to their glycosidic bonds and are hydrolyzed by colonic bacterial β-glucosidases into active aglycones (emodin, aloe-emodin), meaning bioavailability of the active moiety is dependent on gut microbiome composition. Additional non-anthraquinone constituents include: • Tannins (approximately 3–5% of dried bark), contributing astringent properties. • Lipids and resins (minor). • Volatile oils (trace). • Minerals present in trace amounts include calcium, manganese, and potassium, though quantities are negligible at medicinal doses. • Dietary fiber is present in the bark matrix but not nutritionally relevant given typical dose sizes (300–1000 mg dried bark or equivalent extract). Standardized commercial preparations are typically calibrated to contain 20–30 mg hydroxyanthracene derivatives (calculated as cascaroside A) per dose. Aged bark (minimum 1 year or heat-treated) is required to reduce concentrations of free anthrones, which cause griping and nausea. No significant vitamin content has been documented. Bioavailability note: Oral absorption of intact cascarosides in the upper GI tract is minimal (<5%); therapeutic action is almost entirely colon-dependent, requiring microbial metabolism for activation, with peak effect occurring 6–12 hours post-ingestion.
Cascara sagrada's anthraquinone glycosides (cascarosides A and B) are converted by colonic bacteria into active aglycones that stimulate the enteric nervous system. These compounds increase prostaglandin E2 synthesis and enhance chloride secretion, leading to increased water and electrolyte content in the colon. The result is enhanced peristalsis through inhibition of segmental contractions and stimulation of propulsive contractions.
Clinical evidence for cascara sagrada is limited, with most support coming from traditional use rather than controlled trials. Small observational studies suggest laxative effects typically occur within 6-12 hours of administration. The FDA removed cascara sagrada from over-the-counter laxative products in 2002 due to insufficient safety data regarding long-term use and potential carcinogenic effects. Current evidence relies primarily on mechanism studies and historical usage patterns rather than rigorous clinical trials.
Cascara sagrada can cause abdominal cramping, electrolyte imbalances, and melanosis coli with prolonged use. It may interact with cardiac glycosides, diuretics, and corticosteroids by enhancing potassium loss. Contraindicated during pregnancy, breastfeeding, and in individuals with inflammatory bowel conditions, intestinal obstruction, or appendicitis. Long-term use may lead to dependency and impaired normal bowel function.
