Cinchona News: Need to Cinchona Plantation in Darjeeling.
Amid high promises made by all those who matter, Cinchona plantation in Darjeeling is at shamble despite having sky high potential in the sector of high potential medicines that includes steroids or anti-cancer drugs. Now the demand has started coming up for the plantation's to be declared as a world heritage site.
Cinchona is native of high lands of South America and was introduced in India (Nilgiris) in 1859. It is grown in Nilgiris and Anamalai hills of Tamil Nadu. It is also grown in Darjeeling (West Bengal). It is an evergreen tree, growing to a height of 10-12m with a sparse branching habit. It belongs to the family Rubiaceae. The important species, which are under commercial cultivation, are Cinchona ledgeriana, C.officinalis, c.robusta and C.succiruba.
Climate and Soil
Quinidine, an alkaloid of cinchona bark, is used for its anti-malarial, anti-pyretic and oxytonic actions. But no clinical use is currently made of these properties. In addition to their use in pharmacy, quinine and quinidine and their derivatives are utilized in insecticide compositions for the preservation of fur, feathers, wool and textiles.
Cinchona requires an average temperature of 200C with a relative humidity of 85%. Annual rainfall should be not less than 200cm but distributed atleast 8 months in a year. The best elevation is 1000 to 2000m above M.S.L. without any frost occurrence. Cinchona prefers porous, well drained, fertile soils with a thick cover of organic matter and high moisture holding capacity. The optimum pH range is 4.5 to 6.5
Cinchona is propagated by seeds and vegetatively by cutting, stooling, layering and patch budding. Seeds are sown in raised beds during April and they take about 20-30 days for germination. The healthy seedlings are transplanted in baskets or polythene bags when they are about four months old. Clonal propagation is sometimes done through top working or patch budding.
The area selected for planting should be cleared a year in advance and planted with shade trees like Silver oak and or dedabs. Pits of 30 x 30 x 45cm are dug and filled up with topsoil and other well decomposed organic matter. Seedlings are transplanted in the main field at the spacing of 1.25x1.25m when they are about one year old. Transplanting is done any time when there is sufficient moisture in the field. The other method is to go for high density planting i.e. trees are set out at a spacing of 1.0x1.25m or 8000 plants per hectare and gradually harvested until 800 plants/ha remain after 25 years.
Manures and fertilisers
Cinchona plants are manured with 115kg Nitrogen, 15kg Phosphorus and 115kg Potash per ha per year. Once in 3 to 4 years when the soil pH goes below 4.5 liming @ 1.0 to 1.5 t/ha is recommended.
The main cultural operations are staking the plants in the first three years to prevent wind damage. In young plantations, wind growth may be checked by slash weeding, followed by chemical weeding with paraquot @ 30ml and sodium salts of 2, 4-D @ 25g in 10 litres of water.
The trees are coppiced when they are 8 to 10 years old depending on the vegetative growth. Coppicing consists of pruning the tree at a height of 5cm from the ground level. The stump left on regenerates to produce a large number of shoots but only two or three of these are retained and allowed to grow further while the remaining ones are removed. The trees become ready for the second coppicing within 8 to 10 years from the time of first coppicing. After the second coppicing also, two to three shoots are left to grow further. The trees are finally uprooted in the 30th year when they start declining in vigour. Even though the major harvests are obtained at the time of first two coppicings, some yields of bark are also available from the dead and dying trees and prunings. During the first two coppicings, an yield of 4000kg of dry stem bark per hectare may be obtained and at the final stage of uprooting the tree, the yield of bark may be 6000kg per hectare. The most important alkaloid principle is Quinine which occures in the stem, twig and root bark of the tree. Normally its content range from 3 to 4% as Hydroxy Quinine sulphate.
The extraction of quinine involves beating of the bark with a mallet to loosen it for peeling by hand or knife. The peeled bark is quickly dried to prevent the loss of alkaloids. The fully dried bark is sent to the factories for solvent extraction of powdered bark with slaked lime containing more than 60% of Calcium hydroxide and the alkaloids removed with amyl alcohol or ether. These alkaloids are in turn extracted from the solvents in acidified water, they precipitate out when the water is made alkaline. It is then dried and powdered, and is the starting material for the manufacture of quinine base and other quinine salts. Medicinally, cinchona alkaloids (purified) and their salts are conforming to the latest pharmaceutical standards in various countries.
In the nursery, damping off caused by Pythium is often noticed. Drenching with 0.5% copper oxy chloride is recommended at 10 days interval.
Tea mosquito bugs (Helopeltis antonii) often infest the leaves in the nurseries and also in the mainfield. Spraying with any systemic insecticide will check the incidence.