Cultivation, Collection and Processing of

Crude Drugs

Learning outcomes: After completing this lecture , the student will be able to:

• Understand the advantages of cultivation

• Compare the advantages and disadvantages of method of cultivation

• Describe the Factors affecting cultivation

• Understand the time of collection of plant drugs

• Understand harvesting, drying , garbling packing and storage of crude drugs.

Cultivation, Collection and Processing of Crude Drugs

• Cultivation of medicinal plants offers wide range spectrum of advantages over their wild sources.

• The advantages of cultivation may be briefly summarized as follows:

• It ensures quality and purity of medicinal plants.

• It gives a better yield and therapeutic quality.

• Cultivation ensures regular supply of a crude drug.

• Cultivation of medicinal and aromatic plants leads to industrialization to a greater extent.

• Cultivation permits application of modern technological aspects such as mutation and hybridization.

Methods of cultivation

There are two methods of cultivation; sexual and asexual methods.

I. Sexual method

In this method, the plants are raised from seeds and such plants are known as seedlings.

Advantages of this method:

• Seedlings are long liver and bear more heavily.

• Seedlings are comparatively cheaper and easier to raise.

• Propagation from seed is responsible for the production of seedlings of highly superior merits which may be of great importance to specific producers.

• It is the only method of choice in case other methods can not be utilized.

Disadvantages of this method:

• Generally, seedling trees are not uniform in their growth and yielding capacity as compared to grafted trees.

• They require more time to bear as compared to grafted plants.

• Cost of harvesting, spraying of pesticides, etc is more compared to grafted trees

II. Asexual method

In this method, the vegetative part of a plant such as stem or root is placed in such an environment that it develops into a new plant.

Advantages of this method:

• The plants are uniform in growth and yielding capacity. In case of fruit trees, uniformity in fruit quality makes harvesting and marketing easy.

• Plants start bearing earlier as compared to seedling trees.

• It encourages the disease-resistant varieties of plants.

• Inferior or unsuitable varieties can be avoided.

Disadvantages of this method:

• In comparison to seedling trees, these are not vigorous in growth and are not long-lived.

• No new varieties can be evolved by this method

Factors affecting cultivation:

1. Altitude, temperature and humidity

Altitude for drug cultivation

Optimum Temperature for Drug cultivation

Plant Altitude (metres)

Cinchona 1000 - 2000

Tea 1000 - 1500

Camphor 1500 - 2000

Coffee 1000 – 2000

Senna At sea level

Plant Optimum temperature (°C)

Coffee 13- 21

Cinchona 15- 23

Tea 21 - 32

2.Rainfall or irrigation:

Except the xerophytic plants like Aloe, acacia and few other plants,

most of the plants need rainfall or proper arrangements of irrigation

for their development

3.Soil nature and fertility:

Any type of soil containing less than 0.5% of organic matter is

described as poor. If more than 1.5 to 5% of organic matter is

present, it is described as rich soil. The soil with 0.5 to 1.5% of

organic matter is termed as intermediate soil.

4. Fertilizers

• Chemical fertilizers: Nitrogen, Phosphorous and Potassium.

• Manures: Farm yard manure, castor seed cake, poultry

manures and oil cake.

• Bio-fertilizers: These consist of different types of micro-

organisms or lower organisms which fix the atmospheric

nitrogen in soil and plants can use them for their day to day

use. Example: Rhizobium, Azotobacter, Blue green algae and

Azospirillum.

5. Pests and pest-control:

Large quantity of crude drugs are wasted or destroyed by the

pest. Controls of pests are primary importance to save the

medicinal and aromatic plants.

Collection

• Leaves and flowering tops are collected just before the flowering stage (maturity)

• Flowers are collected just before pollination or before their full expansion

• Barks are collected in spring or early summer when the cambium is active

• Fruits are collected depending upon the part of the fruit which is pharmaceutically important. They are collected either ripe or half ripe, but fully grown.

• Roots are collected in the spring

• Rhizomes are collected when they contain the maximum quantity of food reserve material and chemical constituents.

• The unorganized drugs are collected as soon as they ooze out of the plant.

Harvesting

• Harvesting is an important process in cultivation technology. We

should pay attention to the type of the drug to be harvested and

the pharmaceutical standards which it needs to achieve. It can be

done very efficiently by the skilled workers.

• The underground drugs like roots, rhizomes and tubers are

harvested by mechanical devices such as diggers or lifters.

• Aerial parts are harvested by binders.

• Flowers, seeds and small fruits are harvested by a special device

called seed stripper.

• The seaweeds producing agar are harvested by long handled forks.

Drying

• Drying consists of removal of sufficient moisture content of the crude drug to improve its quality and make it resistant to growth of microorganisms.

• Drying inhibits partially the enzymatic reactions and also facilitates pulverizing or grinding o crude drugs.

• The slicing and grinding into smaller pieces is done to enhance drying.

• Depending upon the type of chemical constituents, a method of drying can be used for a crude drug.

1. Natural (sun-drying):

By direct sun drying or drying in the shed.

2. Artificial drying: It includes drying the drugs in

a. An oven; tray-dryers

b. Vacuum dryers

c. Spray dryer

Garbling

After drying of the plant, it is garbled to remove sand, dirt and foreign organic parts of the same plant which may affect the quality of the drug Packing • The morphological and chemical nature of the drug, its use

and the effects of climatic conditions during transportation and storage should be taken into consideration while packing the drugs.

• Drugs containing volatile oils should be packed on well closed containers to avoid the loss of the oil.

• Cod liver oil is sensitive to sunlight and should be packed in containers which do not permit sunlight.

• Some drugs are sensitive to moisture by becoming flexible, microbial growth or decomposition of active constituents. These drugs should be packed in containers resistant to moisture.

Storage of crude drugs

• Preservation of drugs depends on their physical and

chemical properties. Proper preservation maintains the

quality of drugs. All drugs should be preserved in water-

proof, fire-proof, rodent-proof and well closed containers.

• A number of drugs absorb moisture during their storage and

become susceptible to microbial growth. The moisture

increases the bulk of the drug and causes impairment of its

quality. The excessive moisture facilitates enzymatic

reactions leading to decomposition of active constituents.

• Radiation due to direct sunlight also causes destruction of

active constituent.

• Atmosphoric oxygen is also destructive to several drugs and

hence drugs should be preserved in well-closed containers

and air in containers may be replaced by inert gas like

nitrogen.

• The protection against the insects or mould attack is also

important.

• Form or shape of the drug also plays an important role in

their preservation e.g. colophony is preserved nicely in the

entire form, but if powdered, it gets easily oxidized and

loses its solubility in petroleum ether.

• Most of the drugs need to be preserved at a very low

temperature.