Morphology, Histology and Powder Characteristics of Senna

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BACKGROUND

It is obtained from dried leaf-lets of Cassia angustifolia Vahl. (Indian senna) belonging to family Leguminosae.¹

The present study was aimed to evaluate the morphology, histology and powder characteristics of senna.

REQUIREMENTS

Chemicals: Glycerine water

Phloroglucinol

Chloral hydrate

HCl

Benzene

Sulphuric acid

Apparatus: Microscope

Microscope slide

PROCEDURE

Preparation of mount

The thinnest possible section of plant part is taken on a slide and mounted in a solution of chloral hydrate on slightly warming the solution of chloral hydrate cover the section carefully with cover slip. Care must be taken so that no air bubble should produce within the cover slip. Glycerin also added to the mounted medium.¹

Morphology^1,2

Paripinnately compound leaf about 2.5 to 6.0 cm long.
Leaflet lanceolate with entire margin, reticulately pinnate venation, acute and mucronate apex, asymmetrical base.

Outer surface pubescent with pressure markings
Pale green in colour.
Mucilaginous and slightly bitter taste.

Histology

A transverse section shows

Upper and lower epidermis- polygonal tubular cells with straight anticlinal walls.

Mucilage in the inner periclinal walls, stains red with ruthenium red.
Epidermal trichomes- unicellular, conical, thick walled with warty cuticle, curved at base.
Palisades – a single layer below upper and lower epidermis (isobilateral) continuous over the meristele but absent underneath.

Rubiaceous or paracytic stomata.
Large veins accompanied by calcium oxalate crystals.
Cluster crystals of calcium oxalate in palisade and spongy tissue, crystal sheath in mid-rib region.

Spongy tissue of parenchymatous cells
Meristele of radiate xylem and phloem with an arc of pericyclic fibres below and sclerenchyma above.

Powder characteristics

1. Epidermis with paracytic stomata

2. Calcium oxalate prisms

3. Trichomes

4. Palisade and spongy cells

5. Xylem vessels with annular thickening

6. Crystal sheath

Important constituents

Anthracene glycosides: sennosides A & B.

Identification test

Borntrager test: Boil a few leaves with dilute sulphuric acid, filter hot and to the cooled filtrate add organic solvent like benzene or there (5 ml), shake well. Separate the organic solvent layer and add equal volume of dilute ammonia solution, shake well. Ammoniacal layer acquire rose pink colour.

Use: Laxative

CONCLUSION

Morphology, histology and powder characteristics of senna is evaluated and identified.

REFERENCES

Kokate CK. Practical Pharmacognosy, 4^th edition, Nirali Prakashan, Pune; 1994: 40-41.
http://www.yourarticlelibrary.com/biology/glycoside/tinnevelly-senna-leaves-sources-collection-and-uses.