Rauvolfia (sometimes spelled Rauwolfia) is a genus of evergreen trees and shrubs, commonly known as devil peppers.
- Synonym of Rauwolfia: Rauwolfia root, Sarpagandha
- Biological source of Rauwolfia: It consists of the dried roots and rhizomes of Rauwolfia serpentina Benth.
- Family of Rauwolfia: Apocynaceae. (The name Rauwolfia serpentina has been taken from the name of scientist Dr. Rauwolf and serpentine means snake-like structured root.)
- Geographical source: Several species of plant is distributed in the tropical region of Asia, America, and Africa. It is commercially cultivated in India (mainly in Uttar Pradesh, Bihar, Orissa, Tamil Nadu, West Bengal, Karnataka, Maharashtra, and Gujarat), Srilanka, Myanmar, Thailand, and America.
Cultivation and collection of Rauwolfia:
Rauwolfia develops luxuriantly under a wide range of climatic conditions. It flourishes well in a hot humid climate and grows quite well in shade. The clay loamy soil with a handsome amount of humus is most recommended. Good drainage is supposed to be ideal for its cultivation. The acidic soil having pH 4 favors the growth of the plant. The other requirements for its cultivation are temperature 10-38, Rainfall in the range of 250-500 cm. Sandy soil makes the plant more susceptible to diseases. The propagation is mainly done by seeds, roots, cutting root stump, etc. Propagation from seeds is the method of choice. For this method, the seeds are sown in nursery beds in the month of May-July. The developed seedlings are transplanted in the month of August-September into an open field at a distance of 15 to 30 cm. The fertilizers (like Ammonium sulfate, Urea) and manures (generally bone meal) are supplied to the plants. The plants should be kept free from weeds and they are uprooted when the plants are about 3 to 4 years old. The roots are cut properly and washed with water to remove adhering impurities like sand or other earthy matter. Then it is dried in the air. About 5 kg of seeds is sufficient to cover a one-hectare area. The average yield is about 1200 kg/ hectare but the yield can vary with the type of soil, climatic condition, and age of the plant.
Macroscopical characters of Rauwolfia:
- Colour: Greyish yellow to brown (root bark) and pale yellow (wood).
- Odour: Odorless
- Taste: Bitter
- Size: 10-80cm in length and 1-3cm in diameter.
- Shape: Roots are sub-cylindrical, slightly tapered, tortuous.
- Fracture: Short and irregular.
Rauwolfia contains at least 30 indole alkaloids. The total alkaloidal range is 0.7-3 percent (depends upon the source). Alkaloids are concentrated mostly in the base of the root and can be classified into:
- Indole alkaloid
- Indoline alkaloid
- Indolenine alkaloid
- Oxyindole alkaloid
- Pseudo indoxyl alkaloid
Reserpine is the main alkaloid in Rauwolfia. It also contains oleoresin, phytosterol, fatty acids, alcohols, and sugars. The other alkaloids are Ajmaline, Ajmalicine, Rauwolfinine, Rescinnamine, reserpine, yohimbine, serpentine, serpentinine. Reserpine alkaloid is colorimetrically determined by the reaction in between acidic solution of alkaloid and sodium nitrite.
Chemical Test of Rauwolfia:
- When the fractured surface is treated with concentrated nitric acid, a red coloration is observed.
- When reserpine is treated with a solution of vanillin in acetic acid, it shows violet-red coloration.
Uses of Rauwolfia:
It has antihypertensive activity. The most clinically important compounds are reserpine, rescinnamine, and ajmalicine. Reserpine depletes the catecholamines stored at nerve endings and lowers blood pressure. The drug is used in mild anxiety conditions and neuropsychiatric disorders (due to its tranquilizing effect). Deserpidine and Rescinnamine are used as antihypertensive. Deserpidine shows very few side effects and rescinnamine causes mental depression in higher dose concentrations. Ajmalicine uses in the treatment of circulatory diseases and cerebral blood flows obstruction.
- R. tetraphylla
- R. nitida
- R. densiflora
- R. vomitoria
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