Scientific Name: Rhamnus purshiana/frangula
- Anthraquinone glycosides (glucofrangulin A and B)
- Emodin glycosides
- Laxative (Stimulant)
Mechanism of Action & Pharmacology:
- Anthraquinone glycosides are primarily responsible for providing laxative effects. Will promote peristalsis and effect mechanisms at the myenteric plexus. Anthraquinones are absorbed into the blood and re-secreted into the colon as active anthraquinones where they stimulate smooth muscle contraction. Healthy bacterial flora may be required for full therapeutic potential.
- Emodin has demonstrated anti-tumor and potential anti-leukemic activity.
- Note: Is a gentle, tonifying laxative in low doses and more stimulating in higher doses. Often taken at bedtime.
Safety & Toxicity Concerns:
- Fresh bark is emetic and cathartic.
- Adverse effects include acute intestinal pain and cramping (can often be offset with carminatives).
- Use > 10 days consecutively can lead to dependence on laxatives for a bowel movement to occur.
- Recurrent use or abuse can lead to electrolyte imbalances (particularly hypokalemia), dehydration, and muscle and kidney destruction with hematuria and albuminuria.
- Harmless reddish discolouration of urine and feces may occur.
- May cause pseudomelanosis coli (PMC), a reversible deposition of active anthraquinone glycosides in the colon. Long term use may predispose to colon cancer.
- Avoid in pregnancy, lactation, intestinal obstruction, spastic constipation, acute intestinal inflammation, abdominal pain of unknown origin, and children <12 years old.
- Due to decrease in transit time, may potentially interfere with absorption of practically any medication.
- Avoid concomitant use with potassium-depleting agents (e.g. thiazide diuretics, corticosteroids (Glycyrrhiza glabra), as may cause hypokalemia.
- May affect activity of cardiac glycosides & antiarrhythmic agents if potassium deficiency resulting from long-term laxative abuse is present.