Pharmacognosy I Study Notes

Instructor Information

• Instructor: Assist. Prof. Şule Nur KARAVUŞ
• Institution: Istanbul Medipol University, Faculty of Pharmacy, Department of Pharmacognosy
• Contact Information: sule.karavus@medipol.edu.tr

Course Overview

• Course Title: Pharmacognosy I (PHA3114147)
• Term: Fall 2024
• Lecture #1 Content Overview:
  • Jean Bruneton: Pharmacognosy: Phytochemistry, Medicinal Plants
  • Trease and Evans' Pharmacognosy
  • Pharmacognosy Fundamentals, Applications and Strategy S. Badal
  • The Science of Flavonoids by Erich Grotewold
  • Fundamentals of Pharmacognosy and Phytotherapy by E. Williamson, Michael Heinrich, Joanne Barnes, Simon Gibbons

Flavonoid Biosynthesis

• Biosynthetic Pathways and Compounds:
  • Cinnamoyl-CoA
  • Various compounds like Pinocembrin, Pinobanksin, Chrysin, and Galangin derived from the phenylpropanoid pathway.
  • Mentioned enzymes and their codes (e.g., 2.3.1.74 for phenylpropanoid pathways).

Definition of Pharmacognosy

• Pharmacognosy Definition:
  • Branch of science studying bioactive compounds from biological sources (plants, animals, microorganisms, marine products).
  • Coined as "the study of biologically active natural products."
• Historical Context:
  • First used by Johann Adam Schmidt in 1811, and Anotheus Seydler in 1815.

Historical Aspects of Pharmacognosy

• Early Documentation of Medicinal Plants:
  • Mesopotamian records (∼2600 B.C.E)
  • Egyptian records (∼1800 B.C.E)
  • Chinese texts (∼1100 B.C.E)
  • Indian texts (∼1000 B.C.E)
  • Greek and Roman references (∼500 B.C.E)
  • Dark Ages (∼400-1100 C.E)
  • Notable contributions by Avicenna who published The Canon of Medicine.
• Ebers Papyrus (Ancient Egypt around 1550 B.C.):
  • 110 pages listing approximately 700 herbal, animal, and mineral drugs.
  • Key evidence of early pharmacognosy practices.
• Dioscorides' Materia Medica:
  • Written by Greek physician Dioscorides during his time in the armies of Neron and Vespasian.
  • Consists of 5 books detailing 500 medicinal plants, considered a crucial document in pharmacognosy.
  • Oldest known copy known as the "Vienna Codex."

Avicenna's The Canon of Medicine

• Structure:
  • Book 1: General medical principles.
  • Book 2: Materia Medica - Approximately 800 drugs listed.
  • Book 3: Special Pathology - Diseases of organs.
  • Book 4: Diseases affecting multiple systems.
  • Book 5: Formulary with over 650 remedies.
• Reputation:
  • Ibn Sina (Avicenna) referred to as 'prince of physicians.'

Development of Phytochemistry

• Late 18th-century advances:
  • Introduction to drug synthesis and purification of plant extracts.
  • Significant Events:
  • 1805: Sertürner isolates morphine from Papaver somniferum.
  • 1820: Pelletier & Caventou isolate quinine from Cinchona species, and caffeine from Coffea and Camellia sinensis.
• William Withering's Contribution:
  • Identified Digitalis purpurea for treating edema in 1775, marking advancements in microscopic diagnosis.

Bioprospecting

• Definition:
  • Systematic search for useful products derived from bioresources (plants, microorganisms, animals) aimed at commercialization.

Definitions Related to Pharmacognosy

• Drog vs. Drug:
  • Herbal Drog: Parts of medicinal plants used for medicinal purposes.
  • Medicinal Plant: Defined by the WHO as varieties that can be curative or preventive of diseases or precursors for chemical-pharmaceutical synthesis.
  • Phytotherapy: Treatment utilizing herbs.
  • Phytotherapeutic Products: Medical teas, herbal medicines from herbal drugs.
  • Active Substances: Specific substances like galantamine and ephedrine that are considered pharmaceutical forms and dosages, distinct from herbal medicines.
  • Food Supplements: Determined intake products for supplemental nutrition.
  • Nutraceuticals: Products containing biologically effective higher amounts of food components.

Standardization of Herbal Preparations

• Challenges:
  • Variability in active compound yields based on growing conditions, collection timing, and processing methods.
• Existing analytical methods may fail to determine active compound amounts accurately.

Factors Impacting Medicinal Plant Quality

1. Growing Conditions:
   • Soil selection specific to plant types; e.g., Lavandula spicata thrives in specific soil conditions.
   • Climate considerations: temperature, light, and rainfall impact plant efficacy.
2. Collection Timing:
   • Active compounds may fluctuate based on seasonal changes and daily variations, especially for alkaloids in Papaver somniferum.
3. Drying Methods:
   • Proper drying stops enzymatic reactions. Incorrect methods may lead to compound degradation.
4. Storage Conditions:
   • Materials should be stored in cool, dark, dry places to avoid moisture and heat degradation.
5. Stabilization Techniques:
   • Post-harvest enzyme activity must be managed to maintain quality.

Plant Collection Guidelines

1. Leaves: Collect during blooming.
2. Flowers: Before full opening, or while in bud.
3. Underground Parts: After above-ground plant parts are dried.
4. Shells: After shedding leaves.
5. Seeds/Fruit: Collect upon ripening unless noted differently.
6. Weather Considerations: Avoid collecting leaves, flowers in rain but allow roots in rainy conditions.

Example of Modified Natural Products: Quinine

• Historical impact as an anti-malarial drug derived from Cinchona officinalis.
  • Introduced in 1632 as tea from bark; isolated in 1820.
  • Resistance issues noted from 1910 onwards.

Contributions of Artemisinin and Modern Research

• Current Innovations by Prof. Youyou Tu (2015 Nobel Prize):
  • Discovery and standardization of artemisinin derivatives for treating malaria, contributing significantly to lives saved.

Research References

• Notable Study: Newman, D. J., & Cragg, G. M. (2020). "Natural products as sources of new drugs over the nearly four decades from 01/1981 to 09/2019."
  • Statistics on drug approvals from various sources highlighting the role of natural products in drug development.