Rheum officinale Baill., Rheum palmatum L. (Polygonaceae)
Rheum tanguticum Maxim.
Note that Indian rhubarb (Himalayan rhubarb) consists of the dried root of Rheum emodi Wall, or some other related species of Rheum.
Note also that the root of Rheum rhaponticum Willd (English rhubarb, Garden rhubarb) sometimes occurs as an adulterant in rhubarb and pharmacopoeias specify a test for its absence.
Compound Rhubarb Tincture (British Pharmacopoeia 2009); Rhubarb (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4).
Anthraquinone glycosides are major components of rhubarb. It contains chrysophanol, emodin, rhein, aloe-emodin, physcion and sennosides A to E. Various tannins, stilbene glycosides, resins, starch and trace amounts of volatile oil are also present.
Indian rhubarb contains similar anthraquinones, but English rhubarb contains only chrysophanol and some of its glycosides.
Use and indications
For information on the pharmacokinetics of an anthraquinone glycoside present in rhubarb, see under aloes.
No further interactions with rhubarb found; however, rhubarb (by virtue of its anthraquinone content) is expected to share some of the interactions of a number of other anthraquinone-containing laxatives, such as aloes and senna9. Of particular relevance are the interactions with corticosteroids and potassium-depleting diuretics.