Isolation, Identification & Analysis of Reserpine (Rauwolfia)
Synonym: sarpagandha,
Chhota-chand, Hindi : Chandrika
B. S.: Resrpine
is indole alkaloid obtained from dried roots and rhizomes of Rauwolfia
serpentina
Family: Apocynaceae
G.S.: It
is widely distributed in West land and in shady forests in Punjab eastward to
Nepal, Sikkim, and Assam in India; Bhutan, Pakistan, Java and Thailand, etc.
Plant Habitat: Its
grows spontaneous in tropical forests (temp,10°C to 40°C), at altitude up to
about 1200 m.
Method of Cultivation: Seed
propagation, root culture or stem cutting.
Harvesting: Collected
in October-November after hot and dry period. In Indian Pharmacopoeia
collection of roots of 3 to 4 years old plants.
Odour : Odourless
Taste : Bitter
Size : 2
to 15 cm long and 3 to 22 mm diameter.
Shape: cylindrical,
slightly tapering & tortuous.
External Features : Roots
and rhizomes are nearly similar but rhizomes can be made out by the presence of
small central pith.
Microscopy
Chemical Constituents :
i. Alkaloids- Indole
alkaloids (1.5 or 3%) present.
ii. Weakly basic Indole
type (pH 7 to 7.5)
iii. Reserpine group – Reserpine,
Rescinnamine, deserpidine.
iv. Tertiary indoline
alkaloids (pH-8). Ajmaline group- Ajmaline and Ajmalicine.
v. Strongly basic
anhydronium bases (pH-11).
vi. Serpentine group – Serpentine,
Serpentinine and Alsotonine.
Extraction and
Isolation
(Method- I )
1. Root powder and
moisten with 10% NaHCo3
2. Extract above
mixture with benzene until it give positive reaction with HgI2.
3. Filter it &
conc. Add ether and dilute HCL to it. Shake well.
4. Separate acid layer.
5. Again washed with
ether. Make alkaline with ammonia.
6. Then extract above
solution with chloroform.
7. The chloroform
extract washed with 10 % Sod. carbonate.
8. Separate chloroform
layer and evaporate to dry.
9. Dissolve it in
methanol to get crystals of reserpine.
Extraction and
Isolation
(Method II)
Dried Rauwolfia roots powder with 90% alcohol in
soxhlet apparatus. Filter the alcoholic extract and evaporate to dryness.
Extract the residue with the mixture of ether-chloroform -90% alcohol
(20:8:2.5). Filter and add dilute ammonia to filtrate. Add water to precipitate
the crude alkaloid mixture. Collect the precipitate and dry. Dissolve the
residue in H2SO4 (0.5 N). Add ammonia to the above
solution to liberate alkaloid salts. Extract the solution with 3 portions of
chloroform. Evaporate the chloroform to obtain total rauwolfia alkaloids. Separate
the reserpine from the crude extract by column chromatography separation
technique.
Take sample to this add
ethanol and vanillin in acetic acid. It shows violet-red color indicates
presence of reserpine.
UV detection: 268 nm.
Estimation
TLC Method-I
Stationary phase : silica gel plates
Mobile phase : Toluene: Ethyl acetate: Diethyl amine (70:20:10)
Spraying reagent:.
Dragendroff reagent
Rf Value : Reserpine
(Rf 0.45)
Estimation
HPLC Isocratic Method
Stationary phase : : C18
Mobile phase : Water
and acetonitrile.
Flow rate: mobile phase is 1 ml/1
min.
Injection volume: 20
µl at 25°C.
Uses:
1. Rauwolfia is used as
hypotensive and tranquillizer.
2. Used in anxiety
condition and other neuropsychoiatric diseases.
3. Sedative – calm down
activities and excitement.
4. Stimulates the
central of peripheral nervous systems (Ajmaline group).
5. The decoction of
root is used to increase uterine contraction in difficult cases.
6. The extract is used
for intestinal disorders and as anthelmintic bitter tonic and febrifuge.
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