Page 137 - Pharmacognosy-II (06-PG 303)
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Subterranean stems containing Glycosides
1. Rhubarb
Botanical origin: Rhubarb consists of the whole or cut, dried underground parts
of Rheum palmatum L. or of Rheum officinale Baillon or of hybrids of these two
species or of a mixture (Polygonaceae).
• It contains not less than 2.2 per cent of hydroxyanthracene derivatives,
expressed as rhein, calculated with reference to the dried drug.
Constituents:
1- Hydroxyanthracene derivatives (2–5%): emodin, aloe-emodin,
chrysophanol glycosides, sennosides A–F. Chrysophanol was considered to
produce the purgative action.
2- Tannins: Hydrolysable and condensed
3-Others: Calcium oxalate, resins, starch (about 16%), stilbene glycosides.
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