1. Anthraquinone Glycosides

2. Senna Leaf (Folium Sennae)
Origin: the dried leaflets of Cassia acutifolia known as Alexandrian Senna, and Cassia angustifolia known as Indian Senna F. Leguminosae
Morphology: leaves are compound, paripinnate, petiolate. Leaflets are lanceolate, with acute mucronate apex, entire margin and asymmetric base.

3. Powder: light green having mucilaginous slightly bitter taste, showing fragmentsof:
Epidermal cells, with paracytic stomata, contains pectose type of mucilage.
Non-glandular hairs, unicellular, curved covered with warty cuticle, appearing from cicatrix.
Palisade cells.
Crystal sheath: parenchyma cells arranged in files surrounding fibres, each cell contains prism of calcium oxalate.
Xylem vessels.
Clusters of calcium oxalate.

4. Active constituents:
Anthraquinone glycosides: sennosoides A and B (dianthrone type)
Aglycones of free anthraquinones: rhein, aloe, emodin.
Pectose type of mucilage.
Uses: laxative or purgative used in acute constipation and in case of:
Haemorrhoids, anal fissures, x-ray examinations, before and after abdominal surgeries.
Chemical tests:
Rhuthenium red: for mucilage
Modified Borntrager's test: for dianthrone glycosides gives rose red colour.

5. Rhubarb, Rheum, Chinese Rhubarb (Rhizoma Rhei)
Origin: the dried rhizome and big roots of Rheum palmatum, R. officinale or of other species of Rheum excepting Rheum rhaponticum F. Polygonaceae, grown in China and Tibet and deprived of most of its bark.

6. Powder: reddish brown to yellowish brown in colour with characteristic aromatic odour and bitter astringent taste, shows fragments of:
Parenchyma with starch granules.
Non-lignified xylem vessels.
Large cluster crystals of calcium oxalate.
Medullary ray cells with brownish content giving reddish-pink colour with KOH.
Absence of fibres, sclereids and lignified vessels.

7. Active constituents:
1- Free anthraquinone: rhein, chrysophanol, emodin, aloe-emodin
2- Anthraquinone glycoside.
3- Astringent compounds: catechin, epicatechin, free gallic acid, glucogallin.
Uses:
In small dose: bitter stomachic and intestinal astringent.
In large dose: purgative followed by astringent effect.
Chemical tests:
Borntrager's test: rose-red colour.
Microsublimation: yellow needle crystals which gives red colour with KOH.
Test for purity:
When the powder is examined in ultra-violet radiation, no shining violet spots are seen ( to assure the absence of Rhapontic Rhubarb).