Medicinal Plants Collection and Drying Techniques

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Questions and Answers

What type of incisions are made for the removal of bark?

Longitudinal incisions (correct)

Diagonal incisions

Circular incisions

Vertical incisions

When should the collection of fruits take place?

When they are fully ripened

When they are fully mature but not completely ripened (correct)

When they are completely dry

After the flowering season

What is the purpose of garbling during the cleaning process?

To enhance the chemical constituents

To improve the size and shape of the drug

To remove moisture from the drugs

To remove foreign matter such as sand and dirt (correct)

What is one key reason for the drying of crude drugs?

To prevent microbial growth during storage Signup and view all the answers

What is the maximum moisture percentage that fresh plants may contain?

80 to 90% Signup and view all the answers

What must be done to underground organs before the drying process?

They require cleaning and garbling Signup and view all the answers

When should rhubarb be collected to ensure it contains anthraquinones?

In summer Signup and view all the answers

What time of day is optimal for collecting Digitalis leaves to maximize cardiac glycosides?

Afternoon Signup and view all the answers

How does drying facilitate better handling of drugs?

By reducing their weight Signup and view all the answers

What can careful drying help retain in drugs?

Their chemical constituents Signup and view all the answers

At what stage of maturity do solanaceous leaves contain the maximum amount of alkaloids?

Flowering stage Signup and view all the answers

When should flowers be collected to ensure they are rich in their active constituents?

Just at the time of pollination Signup and view all the answers

How does weather impact the collection of medicinal plant leaves?

Wet weather may cause deterioration Signup and view all the answers

What is a recommended practice for collecting bark from trees?

In spring or early summer when cambium is active Signup and view all the answers

When collecting chamomile flowers, what is the ideal state of the flowers?

Just after full expansion Signup and view all the answers

Which active constituent is associated with clove buds at the time of collection?

Essential oils Signup and view all the answers

What is the primary goal of the drying process regarding moisture content?

To comply with pharmacopoeial requirements for maximum moisture content Signup and view all the answers

What should be the drying method for drugs containing volatile oils?

Quick drying Signup and view all the answers

Which drying method is considered the most controlled and preferable?

Drying chambers Signup and view all the answers

What happens to the size and weight of drugs during the drying process?

They generally lose 80-90% of their original weight Signup and view all the answers

Which drying method is used for drugs sensitive to high temperatures?

Freeze drying Signup and view all the answers

What effect does drying have on the texture of drugs?

They become harder and firmer Signup and view all the answers

What is a disadvantage of natural drying methods?

It dries the plant very slowly Signup and view all the answers

For which type of products is freeze drying commonly utilized?

Delicate products like coffee extracts Signup and view all the answers

What occurs to the color of certain drugs when they dry?

They generally become darker in color. Signup and view all the answers

Which drug retains its odor during drying?

Vanilla pods Signup and view all the answers

How does drying affect the taste of Gentian?

It becomes pleasant. Signup and view all the answers

What is generally the effect of storage on aromatic drugs?

They lose their aroma. Signup and view all the answers

In what case is drying carried out quickly to prevent undesirable changes?

For Digitalis leaves. Signup and view all the answers

What happens to drugs containing volatile oils when stored for a long time?

They gradually lose their aroma. Signup and view all the answers

What is a common consequence of hydrolysis caused by moisture in drugs?

Loss of active constituents. Signup and view all the answers

What is an example of a drug that not only loses its active constituents but may also develop an undesirable odor during storage?

Ergot Signup and view all the answers

What is the primary purpose of using dehydrating agents in drug storage?

To overcome the effect of moisture Signup and view all the answers

At what temperature does enzymatic action typically activate in stored drugs?

35 to 45 C Signup and view all the answers

Why should delicate drugs like rose petals be stored in dark brown containers?

To prevent them from turning brown due to light exposure Signup and view all the answers

What is the effect of oxygen in the air on some drugs?

It can lead to oxidation of active constituents Signup and view all the answers

Which of the following is NOT a biological factor causing the deterioration of drugs?

Temperature Signup and view all the answers

What method can be used to control insect infestations in stored drugs?

Heating to about 60 to 65 C Signup and view all the answers

Which storage method is most advisable for preventing damage from rodents?

Packing drugs in glass containers Signup and view all the answers

What is the typical challenge with using fumigants for insect control?

They do not kill the eggs and require intervals of application Signup and view all the answers

Study Notes

Collection and Drying of Medicinal Plants

Medicinal plants must be collected at the optimal time and stage of development to ensure maximum quality and quantity of active constituents.

Time of Collection

Time of Year: The amount and nature of active constituents vary throughout the year. For example, rhubarb contains no anthraquinones in winter, but instead anthranols, which convert to anthraquinones in summer.
Time of Day: The percentage of certain compounds, like cardiac glycosides in Digitalis leaves, is higher when collected in the afternoon than the morning. These glycosides decompose at night but recombine during the day with sugars from photosynthesis. Solanaceous leaves contain higher alkaloids when collected in the morning.

Stage of Development

General Principle: The percentage of active constituents in a drug depends on the maturity and age of the plant.
Example: Solanaceous leaves: Contain maximum alkaloids at the flowering stage. Santonica flowers contain the bitter principle santonin when not expanded, with the amount of santonin decreasing as the flowers expand.
Leaves: Collected at the beginning of the flowering stage, when they are in the healthiest state and contain the optimal percentage of active constituents. Collection should be in dry weather to prevent deterioration or discoloration.
Flowers: Collected at the optimal stage of pollination but before fruits form. Clove buds are collected while chamomile are collected after the flowers are fully expanded.
Barks: Collected during spring or early summer when the cambium is active and can easily be stripped from the trunk or branches. Longitudinal incisions are usually made at intervals, then round incisions are made and the bark is stripped off in long pieces.
Fruits: Collected near the ripening stage, when fully mature but not fully ripened. They must be collected in dry weather.
Seeds: Collected at the ripening stage, with mature seeds separated from the pericarp.
Underground Organs: Collected in autumn or winter(roots, rhizomes, bulbs, corms)

Drying of Crude Drugs

Treatment before Drying: Cleaning and garbling are crucial preliminary steps before drying. Cleaning involves removal of soil particles from underground organs by shaking, brushing, or washing. Garbling is getting rid of foreign material, such as sand or other plant parts, by hand or specialized machinery.
Moisture removal: Important for stopping enzymatic action, preventing microorganism growth (bacteria and fungi), facilitating grinding and handling, enabling easier packing and storage, and lowering transportation costs.
Duration: Fresh plants contain high moisture content (up to 80-90%), and drying takes anywhere from a few hours to many weeks.
Factors for Appropriate Drying Processes: The optimal temperature and speed for drying depend on the plant and the desired outcome. If enzymes need to be active, a slower drying process is required. Quickly drying plants will help maintain the contents that are undesirable to lose. Drying must be done with care to maintain the physical properties and chemical constituents of the drug. The goal is to retain physical characteristics, chemical constituents, and meet pharmacopoeia requirements for maximal moisture content.

Ideal Drying Practices

Natural Drying: Done by natural air in sun or shade. Suitable for plants that are not affected by direct sunlight, such as Senna leaves. This is a slow process.
Artificial Drying: Faster and suitable for some delicate plants. Different types are used depending on the specific need.
Direct Fire/Stoves: Careful application, as the active compounds can be impacted.
Drying Chambers: A controlled environment for drying, using warm air flowing through the system to remove moisture.
Vacuum Drying: Preserves delicate plants sensitive to high temperatures. Airtight chambers connected to a vacuum pump. The vacuum decreases pressure to remove water more rapidly under low temperatures.
Freeze Drying (Lyophilization): Best suited for delicate plants. Water is removed from the frozen state through sublimation.

Drying's Impact on Crude Drugs

Size & Weight: Drugs shrink and lose about 80-90% of their original weight.
Shape & Appearance: Drugs shrink, and the surface shows wrinkles or reticulation. The inner tissues are often softer than the outer tissues.
Texture: Fresh organs are typically firm, while dried plants become harder.
Color: Drugs usually become darker during drying. Some colors change completely. Loss of color due to chlorophyll breakdown in some instances.
Odor: The odor may diminish, change, or develop as a result of drying. Certain aromatic plants develop characteristic fragrances due to the breakdown of compounds.
Taste: Taste can change during drying, becoming more or less pleasant.
Constituents: Drying may affect the active constituents in desirable or undesirable ways. The process may encourage or disallow the production of certain chemical compounds.

Storage of Drugs

General Principle: Proper storage is required for the drugs to maintain their qualities for optimal use as part of the medicine.
Quality deterioration: When drugs are stored in inappropriate conditions, they may eventually lose their qualities.
Undesirable changes: Some drugs undergo undesirable changes during storage such as, loss of aroma in aromatic drugs or developing a bad odor in ergot. Fixed oils may turn rancid, while volatile oils may resinify.
Loss of active constituents: Digitalis and Cannabis might lose active constituents during storage.

Factors for Deterioration

Physicochemical Factors:
Moisture: Causes hydrolysis of active constituents, leading to enzyme activity and fungal growth.
Temperature: Slight increase in temperature accelerates enzymatic action, especially significant for volatile oils—these break down more easily with increases in temperature.
Light: Degrades delicate substances like rose petals and Digitalis leaves. The process is often influenced as UV light degrades materials.
Air (Oxygen): Causes oxidation, decreasing or changing the chemical constituents of the drugs.
Biological Factors:
Molds/Fungi: Attack drugs containing nutritive substances (roots/bulbs).
Insects: Commonly found on powdered drugs, reducing suitability for extracts.
Rodents: Commonly found in the storage structures of medicines.
Methods of Controlling Insects: Heating drugs, fumigation (e.g. using various insecticides), or applying lime, which impedes the insects’ respiratory systems.
Low Temperature Storage: Used for controlling the factors leading to biological deterioration.

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Description

This quiz covers the optimal timing and stages for collecting and drying medicinal plants to ensure the maximum quality of active constituents. It discusses various factors such as the time of year and time of day that affect the composition of these plants. Test your knowledge on the principles of plant maturity and its impact on medicinal properties.