MODULE 2

• Pharmacognosy


  Applied science that deals with the biological, biochemical and economic features of drugs or biological origin and their constituents
• Knowledge of drugs & pharmaceuticals
• Pharmacognosy


  A science that deals with plants and animal constituents
• Flückiger (1828–94): '"the simultaneous application of various scientific disciplines with the object of acquiring knowledge of drugs from every point of view"'
• Pharmacognosy


  Coined the term in 1815 from the Greek words "Pharmakon" (drug) and "gignosco" (to acquire the knowledge of)
• Babylonians made clay models of man and had medicinal plants of 250 species
• Egyptians practiced embalming and used the Papyrus Ebers for human anatomy and use of plants
• Indians had Ayurveda (2500 BC), the "Science of life" and the "Mother of all healing arts"
• Pedanios Dioscorides wrote De Materia Medica or the Medicinal Material (78 AD)
• Claudius Galen (Rome) was the Father of pharmaceutical compounding and created Galen's cerate (cold cream)
• CA Seydler (1815) coined the term "Pharmacognosy" in his book 'Analecta Pharmacognostica'
• Fluckiger defined pharmacognosy as the "Simultaneous application of various scientific disciplines with the objective of acquiring drugs from every point of view"
• Pelletier and Caventou discovered quinine, and Friedrich Serturner discovered morphine
• Natural Substances Discovered


  • Morphine
  • Strychnine
  • Quinine
  • Caffeine
  • Nicotine
  • Atropine
  • Cocaine
• Crude drugs


  Plant exudates that are collected and dried
• Natural substances


  No molecular modification has been made
• Derivatives or extractives


  Chief principles or constituents of crude drugs, extracted using solvents/menstrua
• Indigenous plants


  Native to their countries
• Naturalized plants


  Grown in foreign lands
• Rinorea niccolifera is a metal eating plant that absorbs more nickel
• Geographic source & Habitat


  Region in which the plant or animal yielding the drug grows
• Methods of extraction


  • Infusion
  • Maceration
  • Percolation
  • Digestion
  • Decoction
  • Liquid-Liquid Extraction
  • Distillation
• Collection


  Small scale, improper collection can result in partial or complete substitution, best time to collect depends on plant part
• Young marijuana leaves contain cannabidiol, mature leaves contain cannabinol (THC)
• Harvesting


  Large scale, using manual labor or mechanical devices
• Drying


  Air drying and artificial drying to prevent bacterial, fungal growth and enzymatic degradation, facilitates grinding and milling, curing is a special drying process
• Garbling


  Final step in preparation of crude drugs, removal of extraneous matter
• Packaging, storage & preservation


  To avoid insect attacks, methods include exposing to 65°C, fumigation with methyl bromide, adding chloroform or carbon tetrachloride
• Evaluation of Drugs


  Assessing quality (inherent/descriptive) and purity through qualitative and quantitative assays
• Evaluation methods


  • Organoleptic/Morphological
  • Microscopic
  • Pharmacologic
  • Chemical
  • Physical
• Classification of Drugs


  • Morphology
  • Taxonomy
  • Pharmacologic
  • Chemical
  • Alphabetical
• Constituent


  Mixture of substances
• Secondary plant substance


  Extracted, crystallized and purified
• Active Constituent


  Secondary metabolites that are pharmacologically or pharmaceutically active
• Pharmaceutically active


  Cause chemical changes in the preparation
• Pharmacologically active


  Responsible for the therapeutic activity
• Inert constituents


  No definite pharmacologic activity
• Factors influencing drug biosynthesis/biogenesis


  • Ontogeny or Stage of Development
  • Heredity (genetic composition)
  • Environment (soil, climate, associated flora and method of cultivation)
• Main routes of chemical compound biosynthesis in plants


  • Shikimic acid pathways
  • Acetate-malonate
  • Acetate-mevalonate
• Biosynthesis of Glycosides


  1. Sugar phosphates + uridine triphosphate (UTP) → uridine diphosphate sugar complex

  2. Uridine diphosphate sugar complex + acceptor units → glycoside production