Medicinal Plants - Lecture 3

Study Notes

The lecture was delivered by Dr. Fatma Alzahra at Heliopolis University.
The lecture focused on the preparation of drugs from plants to pharmaceuticals.
Preparation Methods:
- Cleaning: Underground plant parts are cleaned by shaking, brushing, and washing to remove soil.
- Drying: Plants can be used fresh or dried.

Sun Drying: Used when the plant isn't negatively affected by direct sunlight. Plants need to be turned occasionally. Effectiveness depends on weather conditions.
Shade Drying: Used when sunlight causes discoloration.
Oven Drying: Faster drying method. Controlled temperature minimizes chemical alteration. More expensive than sun or shade drying.
Freeze Drying: Used for sensitive herbs. Further details will be provided during the practical session.

Size and Weight Reduction: Typically 80-90% decrease.
Shape and Appearance: Alterations in appearance; for instance, black pepper shows polygonal reticulations.
Texture Changes: Drying may result in a brittle texture.
Color Changes: Some plants, like tea or vanilla, exhibit color alterations during drying.
Odor Changes: Odors can change; for example, green vanilla becomes the aromatic vanillin in dried vanilla.
Active Constituents Changes: Active constituents may transform. For example, glucovanillin converts to vanillin in vanilla.
Taste Changes: Some plants experience taste changes due to chemical transformations during drying (e.g., Gentian becomes sweeter).

Objectives: Reduce space, protect the drug, facilitate easy transport, and ensure easy storage.
Different packing methods cater to different active components:
- Cardiac glycosides and volatile oils are packed in amber-colored, tightly sealed tins or bottles.
- Less sensitive plants are kept in sacks.

Adulteration can be intentional or accidental.
Sophistication (True Adulteration): Intentional addition of cheaper or less effective materials. Examples include adding starch or curcuma to ginger.
Substitution: Replacing the intended herbal material with a completely different one. A common example is substituting clove buds with clove stalks.
Admixture: Unintentional mixing of different herbal parts or unwanted materials. Examples include mixing different flower parts or inappropriate harvest times.

External Factors:
- Environmental Factors: Water, light, temperature, altitude.
- Soil: Soil quality and composition.
Internal Factors:
- Growth Regulators (Hormones) : Hormones play roles during a plant’s development.

Main Elements (Macronutrients): Essential for plant growth (e.g. nitrogen, phosphorus, potassium).
Microelements: Essential in small quantities (e.g., copper, zinc, iron).
Active Elements: Needed in smaller amounts (e.g., calcium, magnesium, sulfur).
Inactive Elements: Some plants need trace amounts of certain elements (e.g., sodium, aluminum, silicon).

Hormones are chemical substances produced by tissues.
These hormones control growth and metabolism.
Hormones work in small quantities to play several roles in a plant (e.g. cell division, cell differentiation, cell growth, development, damage healing, dormancy, bud growth, aging, defense).

Primary metabolites: Essential for plant life, e.g., sugars, amino acids, proteins.
Secondary metabolites: Not essential for plant life but can have varied functions, e.g., attracting insects for pollination, defending against pathogens, and having medicinal properties.