Cascara sagrada comes from a species of buckthorn that is distributed
throughout the American Pacific Northwest and British Columbia. Native
Americans of the region, who called the herb sacred bark, prepared the
aged bark as a tea to ease constipation. By the mid-19th century, the
pharmaceutical company Parke-Davis began producing cascara-based
cathartic agents for export to Europe.
The bark must be aged for 12 months to allow the hydroxyanthraquinone
glycosides chrysophanol, emodin and aloe-emodin, to break down. In the
body, these agents are further degraded via enzymatic activity into
anthrones, which are responsible for reducing transit time in the colon.
Because this herb acts as a bulk-forming laxative, it must be taken with
plenty of water.
