Senna leaf extract is obtained from the dried leaves of Cassia angustifolia (Indian senna) or Cassia acutifolia (Alexandrian senna) through aqueous-ethanol extraction. The primary bioactive compounds are sennosides A and B, which are anthraquinone glycosides that act as stimulant laxatives.
Sennosides are prodrugs that are activated by colonic bacteria to form rhein-anthrone, which stimulates peristalsis and inhibits water reabsorption in the colon. Senna is one of the most widely used natural laxatives with pharmacopeial monograph status in USP, EP, and BP. Commercially, senna extract is used in OTC laxative products, constipation relief supplements, colon cleanse formulations, and pre-colonoscopy bowel preparation.