Medicinal Plants Collection and Drying

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Questions and Answers

What factors influence the quality and quantity of active constituents in medicinal plants?

Type of soil and height of the plant

Proper collection time and stage of development (correct)

Collection tools used and storage methods

Geographical location and weather conditions

At what time of year is rhubarb most likely to contain anthraquinones?

Fall

Spring

Summer (correct)

Winter

When should Digitalis leaves be collected to achieve higher levels of cardiac glycosides?

In the morning

In the evening

In the afternoon (correct)

At night

Which stage of development is optimal for collecting solanaceous leaves to obtain maximum alkaloids?

At the flowering stage Signup and view all the answers

Why is collecting flowers in fine, dry weather important?

To fix the color of the product Signup and view all the answers

When are cloves harvested for optimal quality?

Just before fruit formation Signup and view all the answers

What is the recommended time for collecting barks from trees?

In spring or early summer Signup and view all the answers

What weather conditions should be avoided for leaf collection to prevent deterioration?

Wet weather Signup and view all the answers

What is the primary purpose of drying crude drugs?

To stop enzymatic action and prevent microbial growth Signup and view all the answers

Which of the following statements about the collection of fruits is correct?

Fruits should be collected near their ripening season when fully mature. Signup and view all the answers

What process is referred to when foreign materials are removed from drugs?

Garbling Signup and view all the answers

Which characteristic is NOT essential for the careful drying of drugs?

Enhancement of chemical constituents Signup and view all the answers

When should underground organs such as roots and rhizomes be collected?

In autumn or winter Signup and view all the answers

What is the main reason for shaking, brushing, or washing drugs before drying?

To remove soil and foreign particles Signup and view all the answers

What is NOT a benefit of removing moisture from crude drugs?

Increasing the drug's weight Signup and view all the answers

How are unorganized drugs such as gums and resins typically obtained?

Through incisions in the plant Signup and view all the answers

What is the primary goal of controlling temperature during the drying process?

To prevent thermal degradation of the drugs Signup and view all the answers

What effect does drying have on the color of most drugs?

They may become darker or change entirely. Signup and view all the answers

Which method of drying is most preferable for tightly controlled temperature conditions?

Drying chambers Signup and view all the answers

Which process is likely to occur when drying drugs containing glycosides?

Hydrolysis of the glycoside to produce a different compound. Signup and view all the answers

How does moisture influence the stability of drugs such as Digitalis leaves?

It causes enzymatic hydrolysis of active constituents. Signup and view all the answers

In which drying process would you choose to use a vacuum?

For drying digitalis leaves Signup and view all the answers

What happens to the taste of Gentian when it is dried?

It becomes pleasant. Signup and view all the answers

What effect does drying have on the size and weight of drugs?

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

Which of the following is not an artificial drying method?

Natural drying in the shade Signup and view all the answers

Why must drying of Digitalis leaves be conducted quickly?

To avoid undesirable changes in active constituents. Signup and view all the answers

What happens to the texture of drugs after drying?

They become harder and less durable Signup and view all the answers

What occurs to drugs with volatile oils during storage?

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

Which of the following is a consequence of uncontrolled storage conditions for drugs?

Gradual deterioration of certain drugs. Signup and view all the answers

Why is it important to carry out drying quickly for certain drugs like digitalis?

To preserve volatile oils and prevent enzymatic hydrolysis Signup and view all the answers

Which drying method is particularly suitable for extremely delicate products?

Freeze drying or lyophilization Signup and view all the answers

What is a common change that occurs to flowers during drying?

They lose their color due to anthocyanin destruction. 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 range does enzymatic action typically activate?

35 to 45 C Signup and view all the answers

How can exposure to light affect certain delicate drugs like rose petals?

They cause deterioration and color change Signup and view all the answers

Which of the following is a method to control insect damage in stored drugs?

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

What is the recommended storage condition to prevent oxidation of active constituents in drugs?

Moisture-proof, air-tight containers at low temperature Signup and view all the answers

What type of drugs are particularly affected by an increase in temperature?

Drugs containing volatile oils Signup and view all the answers

What can be a consequence of inadequate storage of nutritive drugs?

They are susceptible to molds and fungi Signup and view all the answers

Which storage material is recommended to avoid spoilage by rodents?

Plastic containers Signup and view all the answers

Study Notes

Collection and Drying of Medicinal Plants

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

Time of Collection

Time of Year: The nature and amount of active constituents varies throughout the year. For example, rhubarb contains no anthraquinones in winter but instead contains anthranols, which are converted to anthraquinone compounds in summer.
Time of Day: The percentage of cardiac glycosides in Digitalis leaves is higher when collected in the afternoon than when collected in the morning. These glycosides decompose overnight and recombine with sugars during the day. Solanaceous leaves contain higher percentages of alkaloids when collected in the morning compared to afternoon.

Stage of Development

The percentage of active constituents in a drug depends on the maturity and age of the plant. For example, solanaceous leaves contain the maximum amount of alkaloids at the flowering stage, while Santonica flowers have a high amount of santonin when not expanded, decreasing in amount upon expansion.
Leaves are best collected at the beginning of flowering, as they're in their healthiest state and contain the optimum percentage of active constituents at this stage.
Collection should be done in dry weather to prevent deterioration and discoloration during the drying process.
Flowers: Collected in fine, dry weather just at pollination time, before fruit formation. Cloves are collected in buds, chamomile flowers after full expansion.
Barks: Collected in spring or early summer when the cambium is active, easily stripped from the trunk and branches. Longitudinal or round incisions are made on the trunk for easier bark removal.
Fruits: Collected near the ripening season, when fully mature but not completely ripened. They should be gathered in dry weather.
Seeds: Collected at the ripening stage of the fruits, separated from the pericarp.
Underground Organs (Storage Tissues): Collected in the fall or winter (e.g., roots, rhizomes, bulbs, corms).
Unorganized Drugs: (e.g., resins, gums, latex) collected in dry weather, usually obtained by making incisions in the plant.

Drying of Crude Drugs

Fresh plants typically contain 80-90% moisture. Drying removes water, taking hours to weeks.
Drying is necessary to:
- Stop enzymatic action that changes active constituents.
- Prevent microbial growth (bacteria and fungi).
- Facilitate grinding and handling.
- Facilitate packing and storage.
- Lower transportation costs due to weight reduction.
Careful drying is important to:
- Maintain physical characteristics.
- Keep chemical constituents intact.
- Meet pharmacopoeial requirements for maximum moisture content.
Important factors for drying:
- Use the lowest possible temperature,
- Carry out drying as quickly as possible.
Drying speed depends on the drug:
- Slow drying for drugs requiring enzymatic reactions (like Vanilla pods),
- Fast drying for drugs sensitive to enzymatic hydrolysis or containing volatile oils (like Digitalis).
Methods of Drying:
- Natural drying: Using natural air, either in sunlight or in shade (e.g., Senna leaves, flowers). This method is slow.
- Artificial drying:
  - Direct fire: Used cautiously to avoid damaging the drug.
  - Stoves: Used for drying.
  - Drying chambers: A controlled method where drugs are placed on shelves in a chamber with regulated air flow.
  - Vacuum drying: Used for temperature-sensitive drugs; tight chambers connected to vacuum pumps lowering pressure and speeding moisture removal.
  - Freeze drying (lyophilization): A delicate method for drying sensitive drugs removing water content by sublimation.

Treatment of Drugs Before Drying

Cleaning: Underground organs need cleaning and garbling (removal of soil and other foreign matter) before drying by shaking, brushing, or washing with water.
Garbling: The removal of foreign matter like sand, dirt, or other plant parts by hand or special machines or using a magnet to remove metallic particles.

Drying Effects

Drying changes the following characteristics:
- Size and Weight: Drugs shrink due to water loss (80-90% reduction in weight).
- Shape and Appearance: Loss of water causes wrinkling or reticulation of surfaces (inner surface of bark often getting curved as outer tissues are hard)
- Texture: Fresh organs become harder, while drugs containing starch can become hard (horny).
- Color: Drugs can darken (e.g, tea leaves turn brown), or in certain cases change completely (e.g. green to brown), due to chlorophyll decomposition, or loss of anthocyanin.
- Odor: Natural odors may change or disappear during drying, while some drugs gain an aroma. (e.g., vanilla pods develop a fragrant smell)
- Taste: Taste of some drugs may change from bitter to pleasant, depending on the drying method.
- Active Constituents: Some changes are desirable, leading to optimal constituent forms (e.g., glycoside conversion in vanilla pods). If change in constituents is undesirable, fast drying is essential. Drugs with volatile oils tend to lose aroma with storage.

Storage of Drugs

Drugs can deteriorate during storage if not kept under controlled conditions. Proper storage is a key factor to maintain the quality of herbs. Some herbs quality improves with storage, while others quality degrades.
Factors causing deterioration:
- Moisture
- Temperature
- Light
- Air (oxidation)
- Biological factors (insects, molds, fungi, rodents)
Strategies for preserving drugs:
- Using moisture-proof, airtight containers.
- Storing at low temperatures.
Storage Considerations:
- Aromatic drugs can lose aroma during storage.
- Ergot may develop an unpleasant odor.
- Drugs containing fixed oils may turn rancid.
- Volatile oils may become resinified.
- Digitalis and cannabis may lose active constituents.
Follow specific storage instructions in pharmacopoeias to maintain quality.

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Description

This quiz explores the critical factors involved in the collection and drying of medicinal plants. It examines the importance of timing—both in terms of season and time of day—as well as the plant's stage of development to maximize the active constituents. Understand how these factors influence the quality of medicinal plants.