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

Vinca

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 Vinca

Vinca

Synonym

• Vinca rosea, Periwinkle, Catharanthus

Biological Source

• Dried whole plant of Catharanthus roseus

Family

• Apocynaceae

Geographical Source

• Ornamental plant, US, European and Asian countries

• Indigenous to Madagasgar

Macroscopy

• Erect, pubescent herb with branched taproot

• Colour – Leaves – green, roots pale grey, flowers –
violet, pink white or carmine red

• Leaves – simple, petiolate, ovate – oblong, entire, acute
apex

• Flowers – bractate, hermaphrodite, 2-3 cymose axillary
cluster

• Fruits – follicle

• Odour – Characteristics

• Taste – Bitter

Microscopy

Vinca –
Powder characters

Organoleptic characters: Taste, Colour, odour, taste

Active Constituents:

• Large number of alkaloids are present

• 20 dimeric indole – dihydroindole alkaloids – Vincristine,
vinblastine – Oncolytic activity

• Other alkaloids – ajmalicine, serpentine, lochnerine,
tetrahydroalstonine

Chemical tests:

• General chemical tests for alkaloids

• Dragendroff’s test

• Mayer’s test

• Wagner’s test

• Hager’s test

Uses:

Substitutes

• C. ovalis

• C. longifolius

• C. pussilus