Medicinal Plants Course Lecture 4

Study Notes

Medicinal plants course, Pharm D Clinical Program-Level I, 2024, taught by Heba El-Nashar, Ph.D.
The course covers topics related to medicinal plants, including their introduction, historical overview, natural products, taxonomic classification, and biological activity.
Also includes propagation methods, factors affecting plant growth, crude drug production, adulteration, and examples of medicinal leaves, flowers, barks, and herbs.
Professor Dr. Heba El-Nashar teaches the introductory lectures.
Other professors teach specific topics like medicinal leaves, flowers, examples, barks, and herbs.

Topics include Production of Crude drugs, Adulteration of Medicinal Plants, and Detection of Adulterant Identity.

I-Collection: Ensure maximum quality by collecting at the appropriate season and specific stage of development/age (e.g., rhubarb, anthraquinones in winter; some fruits unripe).
Preparation: Cleaning, garbling (removing impurities), drying, curing, packing, and storage.

Cleaning and Garbling: Underground organs are cleaned from dirt and soil via brushing or washing. Sometimes, parts like rootlets or stalks are removed. Garbling removes extraneous matter like sand and unofficial plant parts.
Drying: Fresh organs contain high moisture. Drying reduces this. Drying methods include natural sun-drying (shaded or direct sunlight) and artificial drying which is used in areas where natural drying isn't suitable, and is faster.
Drying Chambers: Enclose the materials and use controlled heat; Temperatures for leaves, herbs, flowers, bark, and roots differ.
Curing: A fermentation or hydrolysis process applied to drugs before drying.
Packing: Loose or under pressure to protect and prevent deterioration. Moisture-proof packing for prone-to-deterioration drugs when transported.
Storage: Final step, crucial for preventing deterioration over time. Drugs are stored in moisture-proof, air-tight, light-proof containers at low temperatures.

Time of the year (Seasons): Plant constituents vary in amount and nature throughout the year (e.g., rhubarb, colchicum, hyoscyamus).
Time of the day: Plant constituents vary in amount depending on collection time (e.g., digitalis leaves, solanaceous leaves).
Stage of Maturity and Age: Plant constituents vary by maturity stage (e.g., santonica flower, solanaceous leaves).

Physicochemical Factors: Moisture, light, temperature, and oxygen. Moisture causes enzyme activation, promoting microbes. Light affects color or causes fading. High temperatures activate enzymes (decomposition), and oxygen causes oxidation (rancidity or resinification).
Biological Factors: Bacteria, molds, insects, and rodents. Bacteria affect starchy/cottony drugs, while molds create clinging particles in powdered drugs. Insects and rodents can damage and render drugs unusable.

Sophistication: Adding inferior material. (e.g., ginger with wheat flour, beeswax with paraffin wax).
Substitution: Replacing the genuine drug with a different article/lower quality variety (e.g., Senna with dog or exhausted drugs, kernels for almonds).
Admixture: Accidentally mixing one substance with another (e.g., argel instead of Senna leaves).
Deterioration: Destruction or removal of valuable active constituents (e.g., whole cloves from which the oil has been removed).
Spoilage: Degradation via fungi/bacteria (e.g., moldy coffee, wormy rhubarb).
Inferiority: Low percentage of active constituents in the substance (e.g., Nux Vomica seeds with low strychnine).

Inspection of morphology: Observing physical characteristics
Histology and Microscopic Examination: Examining tissue structures, trichomes, stomata, etc., for precise identification (Palasade Ratio, Vein Islet Number).
Microscopic Linear Measurements: Evaluating size of starch granules or phloem fiber dimensions to identify various plant parts or species.
Quantitative Microscopy: Counting starch grains, sclerieds, or epidermal cells to distinguish different drugs or varieties.
Solubility and Physical Constants: Examining solubility in differing organic solvents to identify specific oils/oleo-resins.
Qualitative Chemical Tests: Using chemical reactions to identify specific substances (e.g., Ammi visnaga with KOH).
UV Light: Identifying adulterants like different types of rhubarb varieties.
Assays: Measuring active constituents (e.g., alkaloids, volatile oils) to evaluate the quality of the drug.

Deterioration: destruction/removal of active constituents during extraction/distillation or other undesirable conditions.
Adulteration of ginger: Sophistication (using wheat flour).
Vanillin preparation: Curing stage is essential.