Properties

• Volatile oils


  Essential or Ethereal oils
• Why are they called Essential/Ethereal oils


  Due to its essential uses and odorous property
• Uses of volatile oils

  • Perfumery
  • Humidifiers to emit odor
• Volatile oils are colorless, but upon standing become darker in color due to oxidation and resinification
• Why they are called volatile

  They evaporate in room temperature, ready evaporate in air
• Essential oils in conifers can be found in all tissues
• The petals of the rose plant yield essential oils
• Essential oils in mints are primarily located in glandular hairs found on stems and leaves
• Essential oils from the cinnamon tree are extracted from the bark
• Essential oils in umbellifers are obtained from the pericarp
• Umbellifers

  Flower with umbrella-like structure, e.g. Broccoli
• Essential oils in oranges are derived from the flower petals and rind, known as orange flower oil
• Glandular hairs are the specialized secretory structure associated with the Lamiaceae family
• Piperaceae

  Family where modified parenchymal cells are found as specialized secretory structures
• Apiaceae

  Family known for having oil tubes/vitae as specialized secretory structures
• Families where lysigenous/schizogenous structures are observed as specialized secretory structures


  • Rutaceae
  • Pinaceae
• Protoplasm composed of the living part of the cell which are the Cytoplasm, Nucleus and other Organelles
• Protoplasm

  Releases volatile oils via decomposition of resigenous layer of cells and hydrolysis of certain glycosides
• Hydrolysis of certain glycosides require enzymes
• Types of volatile oils

  • Eleoptene
  • Stearoptene
• Eleoptene

  Hydrocarbon portion of volatile oils, liquid, examples include eucalyptol, eugenol, and methyl salicylate
• Stearoptene

  Oxidized hydrocarbon portion of volatile oils, solid at room temperature
• Eleoptene volatile oils

  • eucalyptol
  • eugenol
  • methyl salicylate
• Stearoptene volatile oils

  • menthol
  • thymol
• General properties of volatile oils

  • Characteristic odor
  • High refractive index
  • Optically active
  • Immiscible with water
  • Sufficiently soluble to impart odor to water (2 ml in 1000 ml)
  • Soluble in ether, alcohol (most organic solvents)
• Volatile oils

  Almost any type of organic compounds (HC, alcohols, ketones, aldehydes, ethers, oxides, esters, etc.)
• Volatile oils

  • Commonly contain over 200 components
  • Only a few possess a single component with a high percentage
• Mustard oil

  Not less than 93% allyl isothiocyanate
• Clove oil

  Not less than 85% phenolic substances a eugenol
• Absence of one component

  May change the aroma of volatile oils
• Sources of volatile oils

  Distilled from natural sources
• Volatile oils do not contain glyceryl esters of fatty acids
• Volatile oils do not leave a permanent grease spot on paper
• Volatile oils do not undergo saponification
• Exposure of volatile oils to light and air

  They oxidize and resinify
• Fixed oils

  Obtained through expression, rendering, or solvent extraction
• Fixed oils are esters of fatty acids
• Fixed oils leave a permanent grease spot on paper
• Fixed oils undergo saponification
• Exposure of fixed oils to air

  They rancidify