isolation and identification of vinnca alkaloids

1. VINCA ALKALOIDS
Presented by Zulie Shingala,
M.Pharm 1st year.
Under the guidance of
Mr. Bhavik Chauhan,
Assistant professor,
Faculty of Pharmacy, MSU Baroda.
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2. Occurence
 Vinca alkaloids are obtained from entire plant of Catharanthus roseus.
 Belonging to family Apocynaceae.
 The plant is native of Madagascar and is found in many tropical and
subtropical countries, especially in India, Australia, South Africa and South
America.
 They called as Indole Alkaloids as they contains Indole ring in its basic
structure.
 The important alkaloids present in Vinca is Vinblastine and Vincristine and
they possess definite anticancer activity. They are Dimer Indole alkaloids.
 Vindoline and Catharanthine are Indole monomer alkaloids.
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3. Biosynthesis of Vinka alkaloids
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6. Extraction of Vinca alkaloids
 The dried leaf material is taken and is extracted with a solution of hot
ethanol–water–acetic acid in a ratio of 9:1:1.
 The solvent is removed and to the residue hot hydrochloric acid solution of
2% is added.
 The pH of the acidic extract is adjusted to 4, for the precipitation of the non-
alkaloidal components, which can be separated by filtration.
 The pH of the aqueous acidic solution is now adjusted to 7 and then extracted
with benzene.
 The benzene layer is evaporated to obtain vinblastine and other alkaloids
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7. Isolation of Vinblastine and Vincristine
 The phenolic materials are removed by the washing the extract with dilute
alkali.
 The washed extract is subjected to chromatography on alumina and elution is
carried out in 18 fractions starting with benzene–methylene chloride (65:35)
mixture to pure methylene chloride.
 Vinblastine recovered in the ninth fraction.
 Further elution of the column results in separating the fractions of vincristine
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8. Characterization
 TLC
 Vincristine dissolved in 25% water in methanol solution, spotted in Silica gel-G
plate and developed using the solvent, acetonitrile: benzene (30:70).
 The dried plates are sprayed with 1% solution of ceric ammonium sulphate in
85% phosphoric acid.
 The Rf value of the appeared spot would be 0.39.
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9. Chemical test for Vinca alkaloids
 1. Mayer’s test :
 Mayer’s reagent (freshly prepared mixture of mercuric chloride (1.36gm) and
potassium iodide (5.00gm) in 10 ml of water) is added to the 3 ml of extract.
 Gives creamy precipitates.
 2. Hager’s test :
 Picric acid solution is added to the extract.
 It gives yellow precipitates.
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10. Reference
 Textbook of Pharmacognosy and Phytochemistry by Biren Shah and A. K.
Seth,1st edition, Elsevier Publications.
 https://www.sciencedirect.com/science/article/pii/S1572599506800414
 https://www.sciencedirect.com/science/article/pii/S1572599506800414
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