Purgative anthraquinone found in several plants, especially Rhamnus frangula. It was formerly used as a laxative, but is now used mainly as tool in toxicity studies. Present in Cascara sagrada Emodin is a purgative resin from rhubarb, Polygonum cuspidatum, the buckthorn and Japanese Knotweed (Fallopia japonica). The term may also refer to any one of a series of principles isomeric with the emodin of rhubarb. (Wikipedia)

Emodin is found in dock. Emodin is present in Cascara sagrada.Emodin is a purgative resin from rhubarb, Polygonum cuspidatum, the buckthorn and Japanese Knotweed (Fallopia japonica). The term may also refer to any one of a series of principles isomeric with the emodin of rhubarb. (Wikipedia) Emodin has been shown to exhibit anti-inflammatory, signalling, antibiotic, muscle building and anti-angiogenic functions (A3049, A7853, A7854, A7855, A7857).