MODULE 2

• Pharmacognosy


  Applied science that deals with the biological, biochemical and economic features of drugs or biological origin and their constituents
• Crude drugs


  Plant exudates
• Natural substances


  No molecular modification had been made
• Derivatives or extractives


  Chief principles or constituents of crude drugs
• Solvent / menstruum


  Liquid or liquid mixture
• Marc


  Undissolved portion
• Indigenous plants


  Native countries
• Naturalized plants


  Foreign land
• Rinorea niccolifera


  Metal eating plant (more on nickel)
• Geographic source & Habitat


  Region in which the plant or animal yielding the drug grows
• Infusion


  Hot water (ex. Tea); short contact action - 3-5 minutes only
• Maceration


  Soaked in solvent for long periods of time
• Percolation


  Filtering of fluids through porous materials; passage through percolate (ex. Simple Syrup USP)
• Digestion


  Not boiling (low heat); <35 - 40⁰ C
• Decoction


  Boiling water
• Liquid-Liquid Extraction


  1. Portioning

  2. Distillation
• Distillation


  Purifying liquid by heating and cooling
• Collection


  • Small scale
  • Improper collection results to partial or complete substitution
  • Collection time - Flower - best to harvest at dawn
  • Bark - spring and summer
  • Root crops - when upper ground portion is about to wither
• Harvesting


  • Large scale
  • Manual labor vs. mechanical devices
  • Mechanical devices: pickers, mowers, binders, swath, steel
  • Manual - for potent constituents
• Drying


  • Air drying and artificial drying
  • Prevent bacterial, fungal growth and enzymatic degradation
  • Facilitates grinding and milling
  • Curing - special drying process
• Garbling


  • Final step in the preparation of crude drugs
  • Removal of extraneous matter (other parts of the plant, dirt, added adulterants)
• Packaging, storage & preservation

  • To avoid insect attacks: Expose drug to 65°c
  • Fumigation with methyl bromide
  • Add a drop of chloroform or carbon tetrachloride
• Evaluation of Drugs


  • Quality (inherent/descriptive in nature) and purity
  • Qualitative and quantitative assays
  • Quality - intrinsic property of drug; type of medicinal principles
  • Quantity - amount
• Organoleptic/Morphological evaluation


  1. Evaluate macroscopic appearance of drug: Shape

  2. Size

  3. Color

  4. Fracture & internal color

  5. Odor

  6. Taste
• Microscopic evaluation


  1. Identity and purity of the drug substance

  2. Adulterant can also be detected microscopically

  3. Staining techniques and reagents
• Pharmacologic evaluation


  1. Preclinical or Bioassay

  2. Living organism or their isolated living tissues are used

  3. Antibiotics, toxins and toxoids and vitamins
• Chemical evaluation


  1. Qualitative and quantitative determination of their active principles

  2. Assay - titration is the best method for determining official potency

  3. Preliminary Phytochemical Screening
• Physical evaluation


  1. Physical characteristic or parameters with the use if physico-chemical techniques

  2. Solubility, sp. Gr., optical rotation, congealing point, refractive index, melting point
• Classification of Drugs


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


  Mixture of substance
• Secondary plant substance


  • Extracted, crystallized and purified
  • Inert matter
• Active Constituent


  • Secondary metabolites
  • Isolated constituent that is either pharmacologically active or pharmaceutically active
• Pharmaceutically active


  Cause chemical changes in the preparation
• Pharmacologically active


  Responsible for the therapeutic activity
• Inert constituents


  No definite pharmacologic activity
• Drug Biosynthesis/Biogenesis is Influenced by

  • Ontogeny or Stage of Development (stage of development)
  • Heredity (genetic composition)
  • Environment (soil, climate, associated flora and method of cultivation)
• Biosynthesis of Glycosides


  1. Condensation products of sugar and the acceptor unit called as aglycone

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

  3. Uridine diphosphate sugar complex + acceptor units → glycoside production
• Glycosides and their biosynthesis

  • Anthracene glycosides
  • Phenol Glycosides
  • Steroid Glycosides
  • Flavonoid Glycosides
  • Cyanogenetic Glycosides
  • Thioglycosides/Isothiocyante Glycosides
  • Saponin Glycosides
  • Aldehyde Glycosides
• Biosynthesis of Phenylpropanoids


  Shikimic Acid biosynthetic pathway → phenylalanine and tyrosine → phenylpropanoids
• Phenylpropanoids


  Phenolic in character; devoid of nitrogen