Rhamnus cathartica L. - Rhamnaceae - common buckthorn, purging buckthorn, European buckthorn, Purgier-Kreuzdorn, Echter Kreuzdorn

Deciduous shrub, 1-3m high, native to Europe, Sibiria, naturalized in northwestern Africa, North America; twig-ends spiny; bark grey when young, later brown; leaves mostly opposite, ovate, shiny; flowers small, yellow-green; berries green when young, mature ones black.

„The bark and fruit were used as a purgative in the past, though their potentially dangerous violent action and side effects means they are now rarely used.“ https://en.wikipedia.org/wiki/Rhamnus_cathartica

Dried berries (Rhamni cathartici fructus) are used as stimulant laxative. Actice constituents are anthranoids of the emodin type (1,8-dihydroxyanthracene derivatives) as glycosides, which are broken down into anthrones when they reach the colon. „Molecular targets include a chloride channel and less importantly the Na,K-ATPase. Anthrones enhance the secretion of water and inhibit its resorption in the colon, so that liquefied stool and a gentle laxative effect is obtained.“
[Medicinal Plants of the World. Ben-Erik Van Wyk and Michael Wink, Pretoria 2004, 267]