BANAJATA

Although, a number of species of Rauvolfia are reported to contain medicinally important alkaloids, only two species, viz., Serpent Wood (Rauvolfia serpentina) and African Serpentwood (Rauvolfia vomitoria) are commercially important and used for isolation of therapeutically important indole alkaloids. The main hypotensive alkaloid - reserpine, which is part of oleoresin fraction, was isolated by Muller and co-workers in 1952, after which the plant was adopted in modern medicine as an effective hypotensive agent and tranquilizer. Rauvolfia serpentina is indigenous to moist deciduous forests of S.E.Asia including India, Bangladesh, Burma, SriLanka, Malaya and Indonesia. Most of the supply of this drug is obtained from wild sources in India. Zaire is the largest producer and exporter of the drug to Europe.

Plant Botany:

Rauvolfia serpentina is an erect, perennial shrub, generally 15 - 45 cm high, but growing upto 90 cm under very favourable conditions. Roots nearly vertical, tapering, as much as 15 cm thick at the crown and long giving it a serpent like appearance, occasionally branched or tortuous developing small fibrous roots. Roots greenish yellow externally and pale yellow inside are extremely bitter in taste.

Rauvolfia vomitoria is a shrub or small tree, 2 - 6 m high, with bitter, white latex. Branches are quadrangular, roots are 5cm or more in diameter. Leaves in whorls or 3-4, may be oblong, obvate, lanceolate or elliptic with pointed apex, 7 - 17 cm long, 2.5 - 7 cm wide, and shining green. Flowers are fragrant, tubular, 5 lobed, somewhat hairy at the mouth, 8.5 mm long, white, numerous, borne in terminal clusters. Fruits in pair or single, ovoid, smooth, 8.5 mm in size and are bright red when ripe.

The plant thrives well in deep fertile soils that are rich in organic matter. It prefers slightly acidic soils (pH 4 - 6.3). Although, the plant is native of tropical humid climate, it grows in tropical and subtropical areas that are free from frost.

The plant can be propagated through seed or vegetatively by root or stem cuttings. How ever, commercial multiplication through seed is advisable. Seed germination in Rauvolfia is very poor and variable. Seed collected during September - November give good results. Nursery beds should be located in a shady place with adequate irrigation facilities. Seeds should be dibbled or planted about 6 - 7 cm apart at a depth of 1 cm. Ideal time for raising the nursery in north India is May-June just before the onset of monsoon, while in South India seeds can be planted with the onset of monsoon. About 5-6 Kg.seeds are required for planting a hectare. Seedlings can be transplanted in the field in July - August after 8 - 10 weeks growth. Density of plant is selected depending on the fertility of the soil and climate of the area where the crop is to be grown.

Under irrigated conditions serpentwood gives optimum yield only after 2-3 years of planting. However under ideal conditions the crop can be harvested even after two years. The ideal time for harvesting the crop is November- December when the plant becomes dormant and the alkaloid content in the root is highest. Harvesting is done by diggingup the roots by trench holes. Roots are lifted, washed and dried upto 10-12% of moisture content. Dried roots are stored in air tight containers at a cool place. An average yield of 1000 kg roots per hectare is obtained. However, under certain conditions yields of more than 2 tonnes per hectare have also been obtained.