Rauwolfia – Source, diagnostic characters, constituents, tests and uses

Rauwolfia

Source, diagnostic characters, constituents,
tests and uses

Objectives

At the
end of this lecture, student will be able to

Discuss
the source, diagnostic characters, constituents, tests and uses of
Rauwolfia

Rauwolfia

Synonym

• Indian snake root, Chootachand, Sarpaganda

Biological Source

• Dried rhizomes and roots of Rauwolfia serpentina contains
not less than 0.15 %  of reserpine group
of alkaloids, calculated as reserpine

Family

• Apocynaceae

Rauwolfia – Macroscopy

• Size

• Shape

• Colour

• Fracture

• Odour

• Taste

Microscopy

Periderm

      1. Cork – Stratified

                  – Smaller, suberized,
unlignified

                  – Larger, suberized,
lignified

      2. Phellogen

      3. Phelloderm

Secondary
phloem

Secondary xylem

Medullary rays

             
Xylem region are lignified

            – Phloem region are not lignified

Starch and twin
prisms of calcium oxalate

Powder characters

Organoleptic characters: Taste, Colour, odour, taste

Active Constituents:

• Alkaloids – Indole alkaloids – Nearly 30 (1.5-3%) – root
bark

• Phytosterols, fatty acids, unsaturated alcohols, sugars
(dextrose, sucrose)

• Indole alkaloids –

Weakly basic indole group

• Reserpine group- Reserpine, Rescinnamine, desperidine

Tertiary indole alkaloids

• Ajmaline group- Ajmaline, ajmalicine

• Serpentine group- Serpentine, serpentinine, alstonine

Chemical tests:

• Freshly fractured surface with Conc. Nitric acid- red
colour in medullary ray

• Vanillin in acetic acid – Violet colour – Reserpine

• Powder + Sulphuric acid in p-dimethyl amino benzaldehyde –
violet to red colour (Indole alkaloids)

• Tincture of drug in UV light – blue fluorescence

Uses:

• Treatment of hypertension (Antihypertensive) and in
certain neuropsychiatric disorders (Hysteria)

• Treatment of insomnia and certain forms of insanity

• Sedative and transquillizing agent (Reserpine group)

• Ajmaline – pharmacological properties similar to quinidine
– cardiac arrhythmias

• Yohimbine – treatment of impotence

Substitutes

R. vomitoria – African rauwolfia – bushy
plant/tree, contains bands of sclereids and large vessels

R. densiflora – absence of stratified cork,
sclerenchyma (cortex and phloem)

• R.tetraphylla – Uniform cork (non-stratified), abundant
sclereids, absence of recinnamine

Summary

• Dried roots of Rauwolfia serpentina with bark
intact, contains not less than 0.15 % of reserpine group of alkaloids,
calculated as reserpine Indole alkaloids – Reserpine – antihypertensive, sedative

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