Senna Leaf

Senna belongs to Anthraquinone class of glycosides.

Glycosides (Non-reducing organic substances) are formed by condensation of hydroxyl group of aglycone and hemiacetal hydroxyl group of sugar.

SENNA LEAF

Biological source: Dried leaflets of Cassia acutifolia (Alexandrian Senna) or Cassia angustifolia (Tinnevelly and Indian Senna). Family: Leguminosae.

Cultivation: Cultivation of  Cassia angustifolia by Planting in Tinnevelly, Madhurai &  Ramnathpurm district of  Tamil Nadu, Cudappa district of Andhra Pradesh, Kutch in Gujarat and Rajasthan.

After 2-3 months of sowing, the harvesting of leaves is done in three stages:-

1.     Plucking-when leaflets are thick, full-grown and greenish in colour.
   2.     After one month-Second plucking.
   3.     After 4-6 weeks last plucking.
   Content of sennoside in leaves is maximum when they are fully grown & goes on decreasing along with maturation of pods.
   After rice crop, senna give best yield.
   Leaflet dried under shade or indoor→for 7-10 days-yellowish green colour/ or under sunlight.
   Protected from light on storage.
   Macroscopic & Microscopic Character: Cassia angustifolia (Tinnevelly and Indian Senna).
   →Yellowish-green colour
   →Taste › Mucilaginous & bitter
   Leaf- Lanceolate, entire, apex is acute with spine at top.
             Trichomes→On both surface.
                              →Unicellular, Conical, Thick walled warty trichomes.
   Stomata-Rubecious (Paracytic)
   Pericyclic fibre (A patch of sclerenchyma towards upper epidermis and above xylem), Cluster sheet, Collenchyma, Calcium oxalate cluster.

	Indian Seena	Alexandrian Senna
Vein-islet No.	19.5 - 22.5	25-29.5
Stomatal Index	17 -20	11.4-13.3
Palisade ratio	7.5 (Upper epidermis)	9.5
	5.1 (Lower epidermis)	7.0

 

 

 

Chemical Constituents :

→Anthraquinone glycosides- Sennoside  A, B- Purgative in Nature

Tutin in 1913 isolated→Rhein and aloeemodin

Stoll in 1941 isolated→Crystalline sennosides A & B

Sennoside A and B= Stereoisomers

Dimeric glycosides with rhein dianthrone as glycone.

In Sennoside A →Aglycone dextrorotatory

In Sennoside B → Aglycone mesoform

The purgative activity of sennoside A and B accounts upto 40-60% activity of crude drug.

Sugar part of these glycosides has transporting function for aglycone upto large intestine and also protective action so that oxidation of aglycone to other very less active anthraquinones is prevented.

 

Other glycoside › Rhein-8-glycoside, Aloe-emodin, Kaempferol, Isorhamnetin

Napthalene glycosides › Tinnevellin glycoside

                                    › 6-Hydroxy musizin glycoside

› Chryosophanic acid found in Senna.

› All glycosides are O-glycosides.

Chemical test: Brontragers test→for Anthraquinone glycosides

Drug + Dilute H₂SO₄ + boil→Filtrate + Benzene/Ether/Chloroform (CHCl₃)→Shaken well→Organic layer + Ammonia → Ammonia layer→ Pink red colour→ Anthraquinone glycosides.

Assay: Biological assay on mice→Number of wet faeces produced by group of mice in 24 hr. counted.

Use: Purgative in habitul constipation Anthraquinone glycosides absorbed first in intestinal tract→aglycone part separated→excreted in colon.

Excreted Anthraquinones→irritate & stimulate colon→movements are increased due to local action.

Increase in peristalsis→reduction in water absorption→ soft and bulk faces.

Griping effect by→Resin or emodin content

Adultered & Substituted by:

Dog senna (Cassia obovata)→Obovate shape of leaf

                                           →1% Anthraquinones

                                          → Papillose cells in lower epidermis, Tapering apex

Palthe senna (Cassia auriculata)→Absence of  Anthraquinone glycosides long   haired leaf.       

→Test-leaf+Chloral hydrate +boil+crimson colour.

Bombay senna/ Mecca/ Arabian senna→Brownish green colour.