Everything you need to learn about medicinal plants cultivation, propagation and growth.
How to Cultivate Cinchona ?
Quinine is one of the most important drugs known and has been of very great help to mankind. It is obtained from the thick bark of a number of species of the genus Cinchona, which belongs to the family Rubiaceae.
As many as five species of Cinchona are distributed in the Andes, the area where the genus originated. The species occur mainly in Peru, Bolivia, Columbia and Ecuador, at elevations of 800 to 2,800 metres. Of these, four species, namely, C. ledgeriana, C. officinalis, C. calisaya and C. succirubra and also some of their hybrids have been commercially grown for cinchona bark, from which quinine is obtained.
India is one of the three countries which are the major suppliers of quinine products to the world market and it earns about Rs. 1 crore annually from the export of quinine salts. Cinchona plantations occupy about 1,600 hectares in the Darjeeling district of West Bengal and about 2,380 hectares in the Nilgiris and the Annamalai hills of Tamil Nadu.
C. ledgeriana Monens. is grown in West Bengal at altitudes of 1,000 to 1,900 metres. It is also grown in Khasi and Jaintia hills and in Tinnevelly district of Tamil Nadu. The plant is a small and weak tree and it attains a height of about 6 metres. Leaves are 5-10 cm long, elliptical in shape and thick and glabrous. Flowers are yellow. Fruits are about 12 mm long capsules, ovoid-lanceolate in shape. The average total alkaloid content of the root of a tree is 7.21% and that of the stem 6.01% and of the branch 4.0%, whereas the contents of quinine are 5%, 4% and 1.98% respectively.
C. officinalis Linn. grows at elevations of 2,000-2,600 metres, chiefly in the Nilgiris. The plant is a slender tree and is about 10 metres in height. Leaves are 10-12 cm long and elliptic. The plant produces 2 cm-long, rose-coloured flowers and about 20 mm long, ovoid, oblong capsules. The contents of quinine in the root, stem and branch are 1.75-4.16%, 2.56-4.42% and 1.44-2.35%, respectively.
C. calisaya Wedd. is a robust tree, 12 metres or more in height. It is grown at lower elevations of 400 to 1,000 metres in the Moyar valley in the Nilgiris, and in Sikkim. It is not suitable for growing in excessive cold and humid conditions. Leaves are oblong, 8-20 cm long, glabrous and thick. Flowers are pale flesh-coloured, in cymes. Fruits are ovoid oblong capsules, 8-17 mm long. The content of alkaloids in the stem bark varies from 3.89 to 7.24% and that of quinine from 0.78 to 5.57%.
C. succirubra Pavon. is a hardy tree, growing at elevations of 1,200-2,000 metres in certain parts of Annamalais and Sikkim. It is a tall, erect tree, which attains a height of 18-20 metres. Leaves are thin, broad, large and elliptical and flowers are rosy in colour. Fruits are 25-32 mm long, oblong capsules. The species can withstand high humidity and drought. The total alkaloid content is 7.6% in the root and 5.5% in the stem. Out of these, quinine constitutes 0.76-1.42% and 1.1-1.74%, respectively.
Under less favourable conditions, a hybrid, C. ledgeriana × C. succirubra is considered to be better. Although it has a lower content of quinine, the tree is more robust. A hybrid, C. officinalis × C. succirubra, called robust is hardy and adapted to a wide range of elevation and temperature. Another hybrid, C. officinalis × C. ledgeriana is grown in Mungpoo in Darjeeling district.
Climate:
Cinchona does well in tropical climate, at elevations of 400-2,800 metres, depending on the nature of the species. High humid conditions, a well-distributed annual rainfall of 250-325 mm and minor variations in maximum and minimum temperatures during the growing season are good for most species. Cinchona is susceptible to frost and water-logged conditions.
Soil:
Deep, well-drained, loam to clayey loam, acidic soils, with pH ranging from 4.5 to 6, on sloping, sheltered locations are considered suitable.
Cultivation:
Propagation is usually done by seeds, which are small and light. They remain viable for a short time. Vegetative propagation can also be done by cuttings and layering. In the case of propagation by seed, the nursery bed for raising seedlings is prepared with a mixture of leaf-mould and sand. About 50 g of fresh seeds are sown in a bed measuring 1 sq. m, during February-May.
The nursery is partially shaded with shade trees and kept moist and weed-free. Seeds germinate within a period of 25-40 days. The seedlings are transplanted in a second nursery at a spacing 10 cm × 10 cm when they are of 4 to 6 months age. After another 4 to 5 months, the seedlings, which are by then 30-50 cm in height, are transplanted in the field proper, at a spacing of 2 m × 2 m and are provided with shade.
Thinning of plants is done when they are 4 to 6 years old, by uprooting 50 percent of the population. The uprooted plants are debarked. More bark is obtained in the 8th year from branches, which are cut off to enable one strong stump to grow. The remaining plants are uprooted when they are 12 years old.
In Indonesia, high quinine content is maintained by vegetative propagation of selected clones, the methods recommended being patch and slit-budding, cincturing, layering, etc. Vegetative methods of propagation are done during the monsoon.
Harvesting:
Harvesting is undertaken from the fifth year onwards, when annual thinning is necessary. The bark is removed from both roots and stems of the uprooted plants with a knife. Sometimes trunks of trees are cut above the ground level and the bark is removed from the cut trunks. The bark is dried artificially at a temperature below 75°C and is then packed in gunny bags and stored.
The dry bark is chemically treated for extraction of different alkaloids, of which by far the most important is quinine, which is a very bitter, white, granular substance. Other important alkaloids isolated from the bark include cinchonidine, cinchonine and quinidine. The percentage of alkaloids is lowest in the twigs, higher in the stem and highest in the root bark. The percentage of total alkaloids increases up to the age of 8-12 years and then begins to decrease.
Uses:
Quinine possesses marked bactericidal action. It is used chiefly in the treatment of malaria. It is also used as a tonic and antiseptic. Other important alkaloids are also used in medicine.
Diseases and Insect Pests:
The common diseases of cinchona are:
(i) Damping off and seedling blight, caused by Macrophomina phaseoli and Phytophthora spp., which can be controlled by removing excess shade, restricting watering and by spraying Perenox or yellow Cuprocide.
(ii) Brown root disease caused by Fomes noxius, which can be controlled by scraping the affected bark and exposing the roots and drenching them with Aretan or Ceresan.
(iii) Pink disease caused by Pellicularia salmonicolor, which can be controlled by burning affected branches and spraying with Bordeaux mixture.
(iv) Black root caused by Rosellinia spp., which can be controlled by the same methods as in the case of no. (ii) above.
(v) Stem canker caused by Botryodiplodia theobromae, which can be controlled by scraping out infected portion and applying Bordeaux paint.
Among the insect pests Holotrichia repitita, Rhizotrogus rufus, Serica nilgiriensis and Popilla chlorion cause a great deal of damage to seedlings of C. ledgeriana in south India, which can be controlled by hand-picking of adults coming to the surface of the soil during summer or by irrigating the seed beds with water mixed with crude oil emulsion; Leaf bugs (Disphinctus humeralis), occasionally found on young leaves, which can be controlled by the same methods as stated above in the cases of other insects.
How to Cultivate Ipecac ?
Ipecac or Ipecacuanha is the dried root or rhizome of the plant Cephaelis ipecacuanha, known in commerce as Rio or Brazilian Ipecac. The plant is a native of Brazil. India is one of the few countries where the crop is grown commercially. It is cultivated by the Govt. of West Bengal in the district of Darjeeling.
Two other states, Sikkim and Assam, also grow the crop, though in smaller areas. The total quantity of dry roots produced in India annually varies from 25 to 30 tonnes. A part of this produce is exported along with emetine salts, which earn a foreign exchange of one million rupees.
Cephaelis ipecacuanha (Brot.) A. Rich. belongs to the family Rubiaceae. The plant is a perennial, evergreen, low, straggling shrub, which attains a height of 50 cm. Stem green, more or less succulent. It produces slender corky rhizomes, 10-30 cm long and 4-10 cm thick, bearing horizontally spreading fibrous roots.
These roots, when young, are smooth, slender and whitish. On maturity, they develop a thick brownish bark with numerous transverse furrows, which give the roots an annulated appearance. These constitute the drug of commerce. Leaves opposite, ovate or obovate, elliptic, dark green with shining upper surface.
Inflorescence is small, cymose. Flowers are white, bisexual, heterostylous and epigynous. Corolla is funnel-shaped. Ovary is inferior and round. Stigma is short. Fruits are globose berries in a cluster. Seed is white, 5-6 mm long and 1.5-2 mm broad, enclosed in a hard testa.
Climate:
A well-distributed high rainfall, at least 200 cm and a temperature range of 10°C-30°C are favourable. Besides, sites at altitudes of 500-600 metres, which are protected from strong winds, are suitable for the crop.
Soil:
Well-drained, moist, sandy loam soil, rich in humus, potash and lime is preferred.
Cultivation:
The plant is propagated from seeds and also from shoot and root cuttings. Seeds are sown by broadcasting or by drilling during the months of January-March in well-prepared, raised seed beds of convenient size, which have been heavily manured. About 35 g seed is sown per sq. metre.
The seed beds are provided with shade during the day and are watered. They are weeded to keep them free from weeds. The seeds germinate in 3-5 months. When the seedlings are about 4 cm in height, they are transplanted with a spacing of 5 × 5 cm in another nursery after the monsoon.
This nursery is prepared in the same way, but with a heavier dose of manure. The nursery is provided with a roof. During following March-April, the seedlings are again transferred to another field with a spacing of 20 × 20 cm. The plants are watered and top-dressed with well-rotted cow dung, once or twice a year. Weeding and watering are continued till the time of harvest. The plants remain in the field for 3 years.
In vegetative propagation, cuttings from root and stem are used. They are first planted in moist sand contained in pans, which are protected from direct sun. Within 2-3 weeks, callus develops from the cuttings. Fibrous roots and new shoots then appear. The young plants are planted in pans and, after sometime, they are planted in beds.
Harvesting:
Roots are harvested when the plants are 2years old and the alkaloid content exceeds 2%. A healthy plant yields 6-8 good roots.
Alkaloids:
The roots of Ipecac contain various alkaloids, namely, emetine, cephaeline, psychotrine, psychotrine methyl ether, and emetamine. Of these, emetine is the most important. The average total content of alkaloids in the Indian crop is 2.5%, of which 1.3% to 1.4% is emetine. The alkaloids are extracted in the form of their salts, emetine sulphate and emetine hydrochloride for marketing.
Uses:
Ipecac is used as an expectorant and emetic, mainly in the treatment of amoebic dysentery. It is also beneficial in cases of diarrhoea and some forms of dyspepsia.
Diseases and Insect Pests:
The common diseases of Ipecac are caused by- (i) Fusarium spp. and (ii) Rhizoctonia spp., both of which infest the seed beds and cause damage to the plants. They can be controlled by sowing resistant varieties and by using suitable fungicides.
The common insect pest is red ant (Oecophylla amarogdina), which can be controlled by spraying 0.25% BHC on the nests. Burning and destruction of the nests may also serve the purpose.
How to Cultivate Rauvolfia (Sarpagandha) ?
The genus Rauvolfia, which belongs to the family Apocynaceae, has several species, of which Rauvolfia serpentina is extremely important with regard to medicinal properties. The root constitutes the drug and contains a large number of alkaloids, reserpine being the most valuable. The species is indigenous to India, Bangladesh, Myanmar (Burma), Sri Lanka and Malaysia.
In India, it is distributed from the Himalayan foot-hills to Kerala and is found to grow up to an altitude of 1,200 metres. The drug is mainly collected from wild plants. However, the cultivation of the plant will probably increase as wild plants become scarcer. About 1,50,000 kg roots of R. sepentina is exported every year from India and 30,000 kg is required for internal market.
Rauvolfia serpentina Benth. is a perennial, glabrous under-shrub, about a metre in height. Leaves are whorled, simple, elliptic-lanceolate, acuminate, entire, with shining, deep green upper surface and pale green lower surface. Inflorescence is terminal, cymose umbelliform panicle. Usually many flowers present on a panicle. Flowers are bisexual, actinomorphic and hypogenous with small subulate bracts.
Calyx 5 is partite, glabrous and bright red. Corolla is tubular with 5 petals, 1-1.5 cm long, rose or pink coloured. Stamens 5, inserted in the dilated portion of the corolla tube. A membranous cupular disc present. Carpels 2 in number; ovary superior and the style filiform. Fruit is a drupe, 4-5 mm in diameter and purplish black when ripe.
Climate:
It prefers tropical to subtropical climate. Fairly heavy rains between June and August are quite suitable for the plant. Atmospheric temperatures ranging from 10°C to 38°C are considered ideal for its growth.
Soil:
The plant grows very well in sandy loam to clayey loam soils, which are rich in humus and slightly acidic.
Cultivation:
The plant has been successfully cultivated in many areas in India, both in the plains and in the hills. R. serpentina is a 1½ to 2-year crop. It can be propagated by seeds and root and shoot cuttings. The crop raised from seeds gives a larger yield of roots, from which the drug is extracted. About 8-10 kg seed is required for one hectare of land.
Only heavy seeds are used for sowing and they are selected by floating them in water. Before sowing, they are usually placed under a moist piece of cloth for 24 hours for softening their hard coat. The seeds are then sown in seed beds, which have already been well-prepared. The sowing is done in April-May, in lines 20 cm apart.
The germination takes place in 3 to 8 weeks. After two months, the seedlings, which attain a height of 5 to 8 cm, are transplanted in well- prepared fields at spacing of 45 cm × 30 cm, 45 cm × 45 cm, 45 cm × 60 cm and 60 cm × 60 cm, depending on the fertility of the soil and the nature of the intercrops.
The area used for transplantation is preferably manured with 45 tonnes of farmyard manure per hectare. Nitrogen, phosphate and potash are applied to the crop at the rates of 90 kg, 45 kg and 45 kg respectively per hectare. 50% of the total quantity of nitrogen is applied along with the entire quantities of phosphate and potash as basal dose and the remaining quantity of nitrogen in two split doses, the first one 75 days after planting and the second during the succeeding spring.
The crop is irrigated every month, from January to May and after 45 days or so during autumn. As many as 5 weeding and hoeing are considered necessary during the entire period of growth. Although Rauvolfia gives higher yield when grown as a pure crop, larger profits are obtained when intercrops, like maize, cowpea or brinjal are raised during kharif and radish, wheat or a cole crop during rabi.
Harvesting:
The roots are dug out during the winter, from November (in north India) to January-February (in south India). Care should be taken not to damage the root bark and thin fibrous roots, which contain larger percentages of alkaloids. The roots are cleaned with water and dried in the sun. They are powdered, strained and stored in proper air-tight containers. The average yield of sun-dried roots is about 1,000 kg per hectare.
Alkaloids:
A large number of alkaloids have been isolated from Rauvolfia serpentina. The alkaloids, namely, ajmaline, ajmalinine, ajmalicine, serpentine isolated in 1931 are not therapeutically important, the important ones being reserpine and rescinnamine isolated in 1952 and 1954, respectively. Although reserpine has been synthesised, there is not much likelihood of its immediately becoming commercially as important as to replace the natural product completely.
Uses:
The plant R. serpentina and its preparations are used for various purposes, chiefly in the treatment of essential hypertension and in certain neuro-psychiatric disorders. Certain preparations are used in insomnia, nervous breakdown and some forms of insanity also.
Diseases and Insect Pests:
The common diseases are:
(i) Mosaic caused by virus, which is found to affect young leaves and inflorescences.
(ii) Wilt disease caused by Fusarium spp.,
(iii) Leaf blight caused by Alternaria spp. produces minor damages.
(iv) Die-back caused by Colletotrichum dematium in humid conditions, which can be controlled by pruning affected branches and by spraying plants with 0.2% Diathane Z-78.
(v) Nematode infestation is found in acid soils.
With regard to insect pests, adults of Anomala polita have been found to damage the leaves in the rainy season, which can be controlled by spraying 0.2% Folidol.
How to Cultivate Opium Poppy ?
Poppy is an annual herb and is a native of Western Asia. It was introduced into India in the early parts of the sixteenth century. It is now cultivated extensively in India, China, Asia Minor and in some other areas. India accounts for about 70 percent of the world’s total production. The crop is grown in this country under a license issued by the Excise Department and a total area of about 24,000 hectares is put under it in certain districts of three states, namely, MP, Rajasthan and UP.
Poppy (Papaver somniferum Linn.) belongs to the family, Papaveraceae. It is an erect, annul herb, attaining a height of 60-120 cm. It rarely produces branches. Leaves are ovate- oblong and flowers large and showy, borne on slightly hairy peduncles. The capsules (5 to 8 in number), borne by a plant are nearly globose to spherical. The unilocular ovary contains numerous ovules and also bears at its apex a flat disc formed by the union of radiating stigmas. Fruit about 4 cm in diameter and green coloured to start with. It gradually changes its colour to yellow.
The dried latex or opium is obtained by incision from the unripe capsules of the plant.
Climate:
Open sunny locations and a moderately cool weather are favourable for the crop. Severe cold spells, frost, cloudy weather, high winds and heavy rainfall during the period when incisions are given to the capsules affect the yield adversely.
Soil:
The crop thrives on well-drained fertile clayey loam to rich sandy loam soils.
Cultivation:
The land is well prepared during September after addition of 25 to 37 cartloads of farm-yard manure and beds of convenient size are then laid out. A heavy supply of nutrient is required by poppy and 100 kg of nitrogen is applied per hectare, one half at the time of land preparation and another half as top dressing in two split-doses when the crop is just a month old and at the flag-leaf stage.
A seed rate of 2.5 to 3.5 kg per hectare is adopted. The seeds are treated before sowing with 1% Agrosan to prevent the attack of seed-borne diseases. As the seeds are very small, they are mixed with sand and sown thinly in rows running 30 cm apart. The suitable time for sowing is mid-October to early-November.
After the seeds have been sown, the rows are covered with a thin layer of soil and a light irrigation is given. Again Irrigation is given after 8-10 days when the seeds are germinating. A number of irrigations, about 15 in all, will be necessary for the crop, depending on the texture of the soil and the variety.
When the seedlings are 5-7 cm tall, thinning is done to have the plants spaced at 20-25 cm. Weeding and hoeing is done every week till the plants have attained a height of 20 cm, and, after that, once a month only. Flowering takes place in 75-80 days or in 105 days, depending on the area of cultivation and the variety.
The petals drop off in 3-4 days and the capsule is ready for lancing or incision in 6-10 days thereafter. The unripe capsules contain the maximum quantity of the alkaloid, morphine, which gets reduced with the ripening of the fruits, whereas the two others, codeine and narcotine, increase with their age.
Lancing:
Lancing of the capsule is done longitudinally in bright sunlight in the afternoon. The latex, which comes out from the incisions, dries during the night and is removed by scraping with a knife early in the following morning. Each fruit is lanced as many as 4 to 6 times. The crude opium thus obtained is stored in earthen pots and dried in the sun.
The dry produce or raw opium has to be stored in closed vessels. This material is sold to the Excise and Narcotics Department. The average yield of raw opium is 13 to 33 kg per hectare. Much higher yields are, however, obtained under very favourable conditions.
Alkaloids:
As many as 25 alkaloids have been identified in the raw opium, of which morphine, theabine, codeine, narcotine and papaverine are important, the first one being by far the most important. The raw opium produced in India contains, about 20% by weight of total alkaloids, which, in turn, have 9-14% of morphine, 5-7% narcotine, 1.25-3.75% codeine, 0.4-1% papaverine and 0.2-0.5% theabine. While the produce obtained from Turkey and the Balkan countries is rich in morphine, its content being 10-21% that from India is richer in codeine and narcotine.
Uses:
Opium and morphine are widely used for relieving pain and are considered valuable as hypnotics. Codeine is a milder sedative than morphine and is useful as a drug that reduces coughing. Opium closely resembles morphine, but its action is slower. It is, therefore, preferred in many cases in the treatment of diarrheas. It is also used as a diaphoretic.
Diseases and Insect Pests:
The common diseases of poppy are:
(i) Downy mildew caused by Peronospora arborescens, which can be controlled by the application of 0.2% Diathane Z-78 or Carbamate dust.
(ii) Powdery mildew caused by Erysiphe polygoni, which can be controlled by dusting with finely powdered sulphur.
The common insect pests are:
(i) Leaf miner (Phyllocnistis spp.), which can be checked by spraying with 0.2% Metasystox or Rogor.
(ii) Cutworms (Agrotis suffura), which can be controlled by flooding the fields so that the insects float on the water and are picked up by birds.
How to Cultivate Isabgol ?
Isabgol is an important drug plant, the membranous covering of its seed constituting the drug. The plant is a native of Iran and is now grown in India in about 16,000 hectares in three districts of northern Gujarat, namely, Mehsana, Palampur and Banaskantha. India is the largest producer of Isabgol and exports Rs. 25 million worth of seed and husk annually.
Isobgol (Plantago ovata Forsk.) belongs to the family, Plantaginaceae. The plant is an annual stem-less or sub-caulescent, softly hairy or woolly herb. It attains a height of about 50 cm and produces many tillers, the number depending on the fertility of the soil and the conditions of weather. Leaves are narrowly linear or filiform, entire or distantly toothed. Flowers are in cylindrical or ovoid spikes. Capsules ellipsoid, about 8 mm long, obtuse. Seeds ovoid- oblong, 3 mm in length, boat- shaped, smooth, yellowish brown in colour.
Climate:
A cool climate and dry sunny weather are necessary during the time the crop matures. Light showers or cloudy weather or mild dew may cause seed-shedding.
Soil:
Marginal light, well-drained, sandy loam to loamy soils with a pH range from 7 to 8 are suitable for the plant.
Cultivation:
After the harvest of the kharif crops, the land is prepared thoroughly, preferably after mixing 15 cartloads of well-rotted farm-yard manure per hectare with the soil. The land is brought to a fine tilth and laid out into beds of convenient size for irrigation. Sowing is done in early November and may be continued till December.
Seeds are sown broadcast at the rate of 7-8 kg per hectare. Immediately after sowing, they are covered thinly by raking the soil. A light irrigation is then given. The seeds start germinating in 6-10 days. A second irrigation and a third one are given after 3 weeks and at the time of spike-formation, respectively.
The crop requires a total of 6 to 7 irrigations and 1 or 2 hand weeding. Usually 25 kg each of N and P per hectare is applied at the time of planting. Another dose of 25 kg of N is applied along with the third irrigation.
Harvesting, Processing and Yield:
The crop is harvested early in the morning to avoid losses due to seed-shedding. The plants are cut close to the ground and the harvested material is stacked for 1 or 2 days and then trampled by bullocks. Winnowing is done and the separated seed is collected. The average yield of seed is one tonne per hectare.
The husk, which is the rosy white membranous covering of the seed, is separated when the seed is processed. Processing consists of crushing and winnowing. Crushing is done with emery grinders. Flat-stone grinding mills are also used for the purpose. After crushing, the material is sieved to separate the kernels.
Uses:
The seed contains over 30% of mucilage and has medicinal properties. The husk contains more mucilaginous matter and is sometimes prescribed instead of the whole seed. The dried seed and husk are used as emollient, demulcent and mild laxative. They are considered very useful in cases of chronic constipation, amoebic and bacillary dysentery and diarrhea.
In indigenous medicine, the seeds are considered to be cooling and diuretic and prescribed for urinary troubles. A decoction of seed is recommended for cough and cold. Poultice made of crushed seeds is sometimes used for rheumatic and glandular swellings.
Diseases and Insect Pests:
The most common disease of the crop is mildew, which can be controlled by spraying wettable sulphur, Karathen and Sulfex, two or three times at fortnightly intervals, after the appearance of infection.
The common insect is white grub, which damages the roots of plants. It can be controlled by treating the soil with 5% Aldrin or Lindane at the time of land preparation.
How to Cultivate Belladona ?
The drug is obtained from the dried leaves, tops and also the roots of the Belladona plant. The species is native to Central and Southern Europe and Asia Minor. It is extensively cultivated in USA, Europe and, to a small extent, in Kashmir in India.
Belladona (Atropa belladona Linn.) belongs to the family Solanaceae. The plant is a tall, branching perennial herb, attaining a height of about 1.5 m. It produces a large tapering root. Leaves on upper branches in pairs. Flowers are solitary, short stalked, drooping and about 2.5 cm long. Calyx 5-lobed, persistent. Corolla campanulate. 5-lobed and dull purplish in colour. Fruit is purplish black berry with remains of calyx attached to it. Berry bilocular and contains numerous seeds.
Climate:
It grows in temperate climate and does well in clear weather and in sunny areas. High humidity is harmful since it encourages the development of root rot.
Soil:
A well-drained, slightly acidic, silty loam to clayey loam soil, rich in humus, is suitable for the crop. It cannot grow under water-logged conditions.
Cultivation:
Although vegetative propagation may be done by planting shoot, root and root-shoot cuttings, propagation through seeds is the easiest and cheapest method. For purposes of sowing, seeds from plants with high alkaloid content should be used. Sowing of seeds is done in rows in a nursery in early spring and germination takes place in 10-20 days.
Since germination percentage is 15 to 40% only, as much as 4 kg seed is required for producing sufficient number of seedlings for planting one hectare of land. When seedlings have 1-3 leaves, they are uprooted from the nursery and transplanted. Transplanting is done in August at a spacing of 45 cm × 60 cm or 60 cm × 60 cm.
In areas of heavy rains during the monsoon, seedlings should preferably be planted on ridges. Before transplantation, 40 tonnes of farmyard manure, 100 kg of diammonium phosphate and 30 kg of potash per hectare are applied to the field. Besides, 20 kg of nitrogen is applied at the time of branching and at every picking of the crop.
Weeding and hoeing are done 2-3 times before the first leaf crop is obtained. Afterwards, 1 or 2 hoeing are usually done before each leaf-picking. During the summer, the crop is irrigated once every 10-15 days.
Harvesting:
The first picking of leaves is done in October. In the following three years, 3 or 4 leaf-pickings are obtained. At harvesting time, on bright sunny days, the plants are cut 20-25 cm above the ground level and, in autumn, 3 cm above the ground level. During the subsequent spring, fresh growth of the stump takes place and flowers are produced during June-August and berries in October. The plants are uprooted after 3 or 4 years and the thick roots are cut into 3-4 cm long pieces.
These pieces are then dried. During drying, the crop loses about 80% of its weight. The average yield of the crop in the first year is 300 kg of leaves per hectare and, in the following years, 750 kg per hectare. Besides this, when the plants are finally uprooted, an additional root crop of 2-3 quintals per hectare is obtained. The produce is stored away from light in a cool and dry place.
Belladona is used in medicine in two forms, Belladonnae folium and Belladonnae radix. The first one is used mainly for preparing medicines for internal use and the other one for preparing galencials for external application. Belladonnae folium consists of dried leaves and tops, which are collected when the plants are in flower. The material is dried rapidly to reduce the weight by about 18% and then stored. The alkaloid content varies from 0.15-0.7%. Belladonnae radix, which consists of the dried roots, is usually harvested in autumn.
The dried roots have an alkaloid content of 0.60-0.66%. They are richest in alkaloids (0.72%) when one year old, but it is uneconomical to take them out then since they are small in size. After cleaning the roots and slicing the large ones among them, they are rapidly dried.
Alkaloids:
The drug from A. belladona usually contains 0.15-0.66% alkaloids, the chief among them being hyoscyamine, hyocine and atropine.
Uses:
The alkaloids are used in pharmacy for their mydriatic, analgesic and antispasmodic properties. The roots are used externally to relieve pain and the leaves and tops are used internally. Belladona stimulates respiration and circulation. It checks the action of secretory glands and produces a sedative action in respect of the movements of the stomach, intestines, uterus, bladder, etc. It overcomes spasm of involuntary muscles, dilates pupils-and relieves pain when applied externally. It is a valuable antidote in cases of poisoning by opium and a few other poisonous substances.
Diseases and Insect Pests:
The common diseases are:
(i) Damping off of seedlings caused by Pylhium spp., which can be controlled by fumigating with Chloropicrin.
(ii) Root-rot also damages the crop, which can be controlled by removing plants along with the soil and burning them. It is a common practice to treat the seeds with Agrosan in order to protect the seedlings from soil-borne diseases.
The most common insect pest is cut worm (Agrotis flammatra), which attacks seedlings in early summer. It can be controlled by the application of 5% Aldrin dust @ 20-25 g per square metre of the nursery before the seeds are sown and also by drenching the bed during the attack of the pest with 1: 19 wettable solution of Chlordane, 2-3 times after every 10 days.
How to Cultivate Foxglove ?
The drug is obtained from the dried leaves of the plant, which is a beautiful herb. It is grown mainly in Central and Southern Europe except in the Mediterranean region. In India, it is cultivated in Kashmir. The plant is frequently grown for ornamental purposes as well as for drug. The leaves contain glycosides, which are used for stimulation of heart.
Foxglove (Digitalis purpurea Linn.) belongs to the family, Scrophulariaceae. In the first year, the plant, which is a biennial or perennial herb, forms a rosette of leaves, and in the second year, an aerial stem, about 1-1.5 metre in height. Leaves usually ovate-lanceolate to braodly ovate in shape, petiolate, and about 10 to 30 cm long and 4 to 10 cm wide.
Inflorescence is a raceme, which bears bell-shaped, purplish flowers, each of which has 5 sepals, 5 petals and 4 didynamous stamens. The ovary consists of 2 carpels and the fruit is a bilocular capsule, containing numerous seeds.
Climate:
Temperate climate prevailing at elevations of 1,200-2,000 metres is suitable for the plant.
Soil:
The plant prefers silty-loam to clayey-loam soils, which are rich, is organic matter. It can grow well in sandy soil if a certain amount of manganese is present.
Cultivation:
Foxglove may be readily grown from seed. A seed rate of 500 g per hectare is used for raising a normal crop. Seeds are sown in early spring in a nursery bed, and the seedlings, when they are 8-10 weeks old, are transplanted in the field at a spacing of 30 cm × 45 cm to 60 × 60 cm, depending upon the fertility of the soil.
The crop requires irrigation and a moderate dose of fertilizers, mainly nitrogenous and phosphatic. The plants put forth flowers in the second year, but the flowering stalks are removed to induce increased leafy growth.
Harvesting:
One harvest of the leaf crop is generally obtained in the month of October in the first year and as many as three harvests are obtained in the second year. The average yield in India in the second year is 600 kg per hectare. Much higher yields up to 1,500 kg per hectare have been obtained elsewhere.
Fresh and full-grown leaves are carefully and quickly dried at 40°C to enable them to be used as the source of the drug. The leaves are stored in the form of coarse powder in air-tight containers in a cool and dry place.
Glycosides:
The tetraglycosides, purpurea glycosides A and B, are the chief constituents of the fresh leaves. On drying, enzymic action takes place and triglycosides, digitoxin and gitoxin, are formed. These are the chief constituents of dried leaves.
Uses:
The medicinal properties of digitalis have been known for a long time. The most active principle is the glycoside, digitoxin. Digitalis preparations are extremely important heart-stimulants and are specific for some types of heart diseases. They enable the heart to contract more powerfully and completely, which helps the circulation of blood and hence improves the nutrition of the body.