Anatomy & Physiology of Medicinal Plants

Anatomy & Physiology of Medicinal Plants (20 HRS)

• Medicinal plants play a significant role in pharmacy, providing many pure natural products.
• Pharmacists should advise patients on common medicinal plants.
• Case studies illustrate the relevance of medicinal plant knowledge and how pharmacists integrate herbal remedies into patient care.
• Patient consultations on herbal supplements and potential interactions should be conducted carefully.
• An integrative approach to healthcare is promoted.

Hypothetical Case Study

• A patient, while under the care of a locum pharmacist, is experiencing unexplained low potassium levels and chronic constipation.
• He uses a "pick-a-cheese" herbal tea (likely Malva sylvestris) as a natural remedy for constipation.
• The plant is identified as Malva sylvestris based on its characteristics (leaves, fruit, flowers).
• The active constituents of the plant, especially polysaccharides, do not seem to be a contributing factor to the patient's symptoms.

How do you react?

• If the patient is using a little-known herbal product, further inquiry is vital to understand the product and potential implications.
• "Pick-a-cheese" may be a widely distributed garden plant and weed also known as "common mallow".
• "Malva sylvestris" may be the correct botanical name, or another species may share the common name.
• Positive identification (botanical) of the plant is made by examining the plant features (leaves, fruits, flowers).

Plants and Drugs

• Pharmacognosy studies medical products derived from living environments (plants and fungi).
• Defining a pharmaceutical plant-derived drug (in pharmacy) can involve:
  • The drug being derived from a plant or part of a plant.
  • The plant material being dried or transformed into a drug.
  • The drug being obtained from a plant, where the resulting product no longer retains the plant's original structure, containing a complex mixture of biogenic compounds (like oils, resins).
• Isolated natural products used in pharmacy are not 'botanical drugs'; they are chemically identified and defined drugs derived from natural sources.

Most Important Plant Organs

• Aerial parts (herbs), include leaves, flower, fruit, bark, root, rhizome, and bulb.
• Majority of botanical drugs come from leaves or aerial parts.
• Botanical drugs are identified by the plant species and the specific part used.
• Adulteration occurs when incorrect plant parts (e.g., aerial parts instead of leaves) are used.

Taxonomy

• Species are the fundamental unit of systematic biology, with high biodiversity (over 500,000 botanical species and over 2 million zoological species).
• Taxonomy is the science of naming and categorizing organisms.
• Taxons are the named units of taxonomy.
• Taxonomy helps structure biological diversity into hierarchical categories.
• Hierarchical categories ideally reflect the natural relationships between organisms.
• Binomial nomenclature is the basic unit of taxonomy and systematics using genus and species names.

Morphology and Anatomy of Higher Plants

• Flower: Essential reproductive organ, often showy to attract pollinators. Key characteristics include size, color, form of fusion, and count of floral parts.
• Calyx: Protective cover during budding, can drop off.
• Corolla: Attracts pollinators; varies in number, size, and fusion, but color is not a reliable identifier.
• Androecium: Stamens producing pollen, important for plant identification.
• Gynaecium: Contains individual carpels; develops into the fruit.
• Pistil: Part of the gynaecium; composed of stigma, style, and gynaecium.
• Gynaecium Position: Epigynous (above the ovary) or hypogynous (below the ovary).
• Inflorescences: Flower arrangements; important for recognizing plants, especially medicinal ones.

Drugs (Based on Plant Parts)

• Flowers: Flowers are important but a minor source of drugs. Examples include chamomile, calendula, arnica, and hops.
• Fruit: Fruits are a significant source of medicinal drugs. Classification: simple, aggregate, and multiple. Examples include caraway, fennel, saw palmetto, schizandra.
• Seeds: Seeds are used in some medicinal products. Examples include white mustard, horse chestnut, ispaghula, and psyllium.
• Stem/Bark: Stem and bark are important for some drugs. Examples include frangula, red cinchona, oak, willow.
• Aerial Parts: Aerial parts (stem, leaves, and flowers/fruit) include ephedra, hawthorn, passion flower, wormwood. Several drugs have leaves substituted by aerial parts.

Leaves

• Leaves originate from the stem and have a crucial role in plant life.
• Leaves facilitate the process of glucose/starch assimilation via photosynthesis, utilizing water, carbon dioxide, and sunlight.
• Leaves convert sunlight energy into chemical energy.
• Photosynthesis produces glucose and starch, essentials for plant growth and energy storage.
• Leaves are adapted to varied environments and display diverse adaptations reflected in anatomical and morphological structures.

Root

• Roots anchor the plant in the ground.
• Roots enable above-ground plant stability.
• Roots absorb water and nutrients; responsible for their conduction throughout the plant.
• Roots are essential for plant nutrition and hydration.
• Roots are storage organs often storing surplus energy (starch and inulin).

Root Composition

• Outer Layer: Forms protective layer.
• Inner Cylinder: Contains xylem and phloem facilitating water, nutrient, and assimilate transport.

Endodermis

• Endodermis is an inner protective layer separating the outer bark from the inner cylinder.
• It provides additional protection to the root structure.

Transport Systems

• Xylem: Transports water and inorganic nutrients upwards.
• Phloem: Transports assimilates (sugars and other organic compounds) throughout the plant.

Root Development

• Primary root develops in a young plant and grows into a thicker structure.
• Secondary roots develop as the primary root matures; often have storage functions.

Rhizomes and Tubers

• Rhizomes and tubers are modified stems and serve similar functions to roots (storage and plant spreading).
• They are categorized separately in botanical terms.

Additional Notes

• Specific plant parts have been mentioned for various medicinal uses.
• Accurate identification and correct plant parts are crucial for pharmacologically effective and safe use.
• Substitution of the desired plant parts can lead to different therapeutic results or none at all, or even be harmful to the patient.