Quiz on Volatiles and alkaloids

• Volatile oils


  Odorous principles found in various plant parts, also called ethereal oils or essential oils
• Exposure of volatile oils to heat, light, and air during storage will negatively affect their chemical composition
• Volatile oils should be stored in well closed amber glass, cobalt blue or aluminum bottles, filled to the neck to expel all oxygen, and stored at low temperatures
• Specific gravity


  • The ratio of the density of a substance to the density of a standard, usually water for a liquid or solid, and air for a gas
• Adulteration


  The action of making something poorer in quality by the addition of another substance
• Volatile oils


  Odorous principles found in various plant parts, also called ethereal oils or essential oils
• Exposure of volatile oils to heat, light, and air during storage will negatively affect their chemical composition
• Volatile oils should be stored in well closed amber glass, cobalt blue or aluminum bottles, filled to the neck to expel all oxygen, and stored at low temperatures
• Specific gravity


  • The ratio of the density of a substance to the density of a standard, usually water for a liquid or solid, and air for a gas
• Adulteration


  The action of making something poorer in quality by the addition of another substance
• Extraneous


  Irrelevant or unrelated to the subject being dealt with
• Components of volatile oils

  • Hydrocarbons
  • Alcohols
  • Aldehydes
  • Ketones
  • Phenols
  • Acids
  • Sulfur compounds
• Volatile oils


  Odorous principles found in various plant parts, also called ethereal oils or essential oils
• Exposure of volatile oils to heat, light, and air during storage will negatively affect their chemical composition
• Volatile oils should be stored in well closed amber glass, cobalt blue or aluminum bottles, filled to the neck to expel all oxygen, and stored at low temperatures
• Specific gravity


  • The ratio of the density of a substance to the density of a standard, usually water for a liquid or solid, and air for a gas
• Adulteration


  The action of making something poorer in quality by the addition of another substance
• Extraneous


  Irrelevant or unrelated to the subject being dealt with
• Components of volatile oils

  • Hydrocarbons
  • Alcohols
  • Aldehydes
  • Ketones
  • Phenols
  • Acids
  • Sulfur compounds
• Specific Gravity


  1. Determined with Westphal balance or pycnometer

  2. Oils lighter than water are rich in HC, alcohols, esters, ketones

  3. Oils with SG more than 1.0 contain chiefly aldehydes, phenols, esters
• Rotatory Power

  1. Measured with a Laurent half-shadow polarimeter

  2. Made at 25ºC

  3. To detect adulteration
• Refractive Index


  1. Determined by Abbe refractometer

  2. Performed at 20ºC except rose oil, 30ºC

  3. Detection of extraneous matter
• Congealing Temp. or Point


  1. The higher the congealing temp. of an oil, the more it is valued

  2. Low congealing temp. indicates partial removal of constituent
• Distillation Range or Limits


  Official standards designate the temperature or range of temperature at which a definite percentage of oil distills
• Fractional Distillation


  1. Separation of various components

  2. Detection of adulteration
• Solubility


  Soluble in organic solvents: absolute alcohol, ether, chloroform, benzene, carbon disulfide
• Assay for Ester Content


  1. Esters + alc. KOH (saponification) → free alcohol and potassium salt

  2. Ester value must be determined

  3. Serves to detect adulteration and to establish the quality of oils valued for their ester content
• Assay for Alcohol Content


  1. Free alcohols + acetic anhydride (boil) → acetates

  2. Using acetylization flask
• Assay for Aldehyde Content


  1. Bisulfite method: Addition of 5% sodium bisulfite sol. → product dissolves in water → nonaldehyde content as water-insoluble layer

  2. Hydroxylamine method: Titration process, addition of hydroxylamine HCl sol.
• Assay for Ketone Content


  Same as Assay for Aldehyde Content, ketone content dissolves in the aqueous layer
• Assay for Phenol Content

  1. Phenols + NaOH → decrease in volume

  2. Phenol constituents are readily soluble in alkali
• Alkaloids


  • Obtained from plant, animal, or synthetic sources
  • Contain organic nitrogen
  • Possess physiologic activity
  • R3N type of formula
  • Possess basic properties

  
• Some common examples of alkaloids


  • Morphine
  • Quinine
  • Ephedrine
  • Nicotine
  • Strychnine

  
• Why assay for alkaloid content

  • Purposes of standardization
  • Proof of purity
  • Commercial evaluation
  • Pharmacological purposes

  
• How to assay for alkaloid content

  • Gravimetric
  • Volumetric
  • Spectrometric
  • Electrometric
  • Physiological
• Factors affecting the amount of alkaloids in crude drugs

  • Age of the plant when collected
  • Season of the year when harvested
  • Soil and climate where grown
  • Conditions of collection, drying and storage
• Factors affecting the quantity of alkaloids in galenical preparations

  • Quality of drug employed
  • Menstruum used in extraction
  • Amount of decomposition during extraction and storage
• Factors affecting the rate of deterioration of alkaloidal preparations

  • Nature of the alkaloid
  • pH value
  • Heat
  • Light
• Free alkaloids


  • Sparingly soluble in water
  • Soluble in most organic solvents
• Alkaloidal salts


  • Soluble in water
  • Sparingly soluble in organic solvents