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Wednesday, September 23, 2009

Vinca rosea, Sadabahar or the Madagascar periwinkle: A plant of great horticultural and medicinal values

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Vinca rosea or Madagascar periwinkle is an important plant taxonomically known as Catharanthus roseus. Catharanthus is a genus of eight species of herbaceous perennial plants seven of which are endemic to Madagascar; the eighth one is native to the Indian sub continent in Southern Asia. Catharanthus pusillus goes by its common name, sadabahar or sadaphuli (perennially flowering) grows in parts of western India with a number of horticulture varieties derived from it. Some botanists classify Vinca as Vinca minor and Vinca major. The lesser periwinkle with lilac blue flowers is called as Vinca minor where as Vinca with purplish blue flowers is called as Vinca major. The minor one is native to Europe and is spread in the British Isles. After introduction into America it has widely spread over much of the eastern continent. Vinca major is reportedly native to the continental Europe and has become acclimatized in England. According to the Flora of Madagascar: Catharanthus, Germplasm Resources Information Network - the seven important wild species of Catharanthus endemic to Madagascar are: C. coreaceus, C. lanceous, C.longifolius, C. ovalis, C. roseus, C. scitulus, and C. trichophyllus.

Vinca minor

Vinca major

Principal morphological features

The plant Catharanthus belongs to the family Apocynaceae of the Order Gentianales under the class Magnoliopsida, dicotyledons.

Catharanthus or Vinca is a woody perennial shrub growing up to a height of about 80 cm. It has glossy, dark green, cauline, opposite, decussate, ex-stipulate, and oval to oblong, simple, and short peteolate leaves with uniform margins and reticulate venation. Stem is erect, cylindrical, branched, glabrous, solid and green in colour. The inflorescence is solitary, cymose- terminal or axillary cyme. Flowers are pedecellate, bracteates, hermaphrodite, actinomorphic, complete, hypogynous, and pentamarous. Corolla is tubular and it consists of 5 petals showing gamopetalous condition. The flower is usually funnel shaped. The androecium consists of 5 stamens that alternate with the petals. These are epipetalous with short filaments and introse anthers that are often linear, oblong or segittate. The gynoecium consists of two carpels, syncarpous, two distinct ovaries with single style and stigma. A nectar secreting disc remains usually present below the gynoecium. The ovary is unilocular with marginal placentation.
Flowers of Vinca rosea are reported to be self sterile and only cross fertilization takes place in them(East, 1919).The pollen tube that develops from the pollen derived from the flowers of the same plant seem to grow too slowly to reach the egg before it dries. On the other hand pollen grains from the other plant develop rapidly enough to achieve fertilization before the eggs deteriorate. The specific factor that causes self sterility in these flowers is yet to be determined by researchers. Fruits are in pairs of elongated follicles.

Catharanthus with white flower

The plant Catharanthus is usually found either growing in the wild or under cultivated conditions. If under cultivation it is for the medicinal or ornamental purpose. It can grow in nutrient deficient soil. In India the native species grows through out the country. However, numerous horticultural varieties having different flower-colours are grown through out the country. Flower colours of horticulture varieties may be white, mauve, peach, scarlet and reddish to orange. It blooms all through the year due to which it is called as sadabahar in Hindi.

Historical background of the plant

As per reports, Phillip Miller(1691- 1771) who was an undaunted and hard working chief gardener of the relatively young Chelsea Physic Gardener of London, England received “some un specified seeds from his colleagues in 1757 at the Jardin des Plantes of Paris, France. These seeds were apparently collected in Madagascar off the coast of Eastern Africa. He planted these seeds and discovered a wonderfully sprouting from verdant, solitary leathery leaves. It looked a bit vine-like periwinkle with which he was familiar and he described it as “Vinca foliis oblong-ovalis integerinous”. Under his binomial system of nomenclature of plants Carolus Linnaeus (1759) added rosea to Vinca to the name of the plant than vine-like periwinkle. Its name was corrected to Catharanthus roseus with red pure flowers Catharanthus means red pure flowers (Catharos means pure in Greek). Finally the taxonomic name Catharanthus was given to the plant by John Edward around 1795. It was also known as Locherna roseus and Ammocalis rosea and the two names are still popular. A similar plant growing in Europe is said to contain medicinal properties and hence was known as “sorcerer’s violet” at that time due to its violet coloured flowers. The classical English name of Catharanthus roseus is called by common English names as Vinca rosea, Ammocalis rosea, and Lochnera rosea, and by occasional English name “Old maid.”

The Catharanthus - a horticultural variety

The plant Vinca rosea is historically known to treat a number of diseases but during current times researchers across the world are studying its valuable healing properties. The plant is now known to contain anti-cancer properties.

Read more about the Madagascar periwinkle's medicinal properties in the section” medicinal Plants”.

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