Glycosides: Anthracene Glycosides Classification
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Questions and Answers

What is the result of hydrolysis of Anthraquinone glycosides?

  • Yielding chrysarobin and water
  • Yielding xylose and calcium
  • Yielding alizarin and glucose (correct)
  • Yielding barbaloin and anthrone

    • What is the use of Alizarin in clinical practice?

  • To assess bone growth
  • To treat arthritis
  • To diagnose Pseudogout (correct)
  • To treat osteoporosis

    • What is the characteristic of anthraquinone glycosides in terms of their color?

  • Yellow-green
  • Orange-red (correct)
  • Colorless
  • Blue-violet

    • What is the primary mechanism of action of laxative glycosides in the gut?

    <p>Irritation of gut mucosa, causing peristalsis</p> Signup and view all the answers

    What is the effect of oxidation with fuming HNO3 on Chrysarobin?

    <p>It yields chrysophanol</p> Signup and view all the answers

    What is the characteristic of Chrysarobin in borax solution?

    <p>It exhibits green fluorescence</p> Signup and view all the answers

    Which type of glycosides is easily hydrolyzed?

    <p>O-glycosides</p> Signup and view all the answers

    What type of glycosides are barbaloin, β-barbaloin, and isobarbaloin?

    <p>C-glycosides</p> Signup and view all the answers

    What is the reduced form of anthraquinone occurring in plants?

    <p>Anthronol</p> Signup and view all the answers

    What type of glycosides has a weak reducing property?

    <p>Anthraquinone glycosides</p> Signup and view all the answers

    What is the medical term for Pseudogout?

    <p>Calcium pyrophosphate dihydrate crystal deposition disease</p> Signup and view all the answers

    Which type of glycoside is difficult to hydrolyze?

    <p>C-glycosides</p> Signup and view all the answers

    What is the purpose of adding H2O2 in the evaluation of anthraquinones?

    <p>To convert anthranols to anthraquinones</p> Signup and view all the answers

    What is the outcome of adding NH4OH to the filtrate in Borntrager's test?

    <p>Red colour indicates the presence of free anthraquinones</p> Signup and view all the answers

    What is the purpose of using an immiscible organic solvent in Borntrager's test?

    <p>To separate the anthraquinones from the plant matrix</p> Signup and view all the answers

    Which of the following is NOT a method for evaluating anthraquinones?

    <p>Chromatographic method</p> Signup and view all the answers

    What is the structure of Alizarin glycoside?

    <p>1-hydroxy anthraquinone-2-O-glucoxyloside</p> Signup and view all the answers

    Which of the following plant species is known to contain Alizarin glycoside?

    <p>R. tinctorum and R. cordifolia</p> Signup and view all the answers

    Study Notes

    Anthraquinones

    • Alizarin glycoside: 1-hydroxy anthraquinone-2-O-glucoxyloside, found in Rubia species (R.tinctorum and R.cordifolia)
    • Hydrolysis: yields alizarin, glucose, and xylose sugars by acid hydrolysis
    • Uses:
      • Moderate laxative
      • Natural dye for red dying of textile fabric
      • Stains tissue containing calcium red immediately (used in clinical practice to stain synovial fluid to assess for basic calcium phosphate crystals in Pseudogout)
    • Pseudogout: a form of arthritis resulting from deposits of calcium pyrophosphate crystals, commonly affecting knees and wrists

    Anthranols and Anthrones

    • Chrysarobin: 1,8-dihydroxy-3-methylanthranol, found in Andira araroba (Leguminosae)
    • Properties:
      • Yields chrysophanol by oxidation with fuming HNO3
      • Gives strong green fluorescence in borax and other alkaline solutions, becoming more distinct upon dilution with water (Schonteten's test)

    C-Glycosides (Aloin)

    • A mixture of C-glycosides obtained from different species of Aloes
    • Includes barbaloin, β-barbaloin, and isobarbaloin (anthrone-C-glycosides)

    Anthracene Glycosides

    • Classification:
      • Anthraquinone derivatives
      • Anthrones and anthronols
      • Dianthrone and dianthranol
      • Oxanthrone
    • Laxative glycosides:
      • 3 oxygenated or substituted forms of anthracene molecule exist
      • Anthraquinone (most common), anthrone (reduced form), and dianthrone (reduced dimer)
      • Phenolic moiety is the irritant principle
    • Characters:
      • Anthraquinone derivatives are often orange-red compounds with weak reducing properties
      • Present in plants either in free form (aglycones) or combined form (glycosides)
    • Tests for Identity:
      • Borntrager's test: in alkali, phenolic groups form phenate complex (bright red)
      • Free anthraquinones: powdered drug is extracted with an immiscible organic solvent, filtered, and treated with NH4OH (or NaOH or KOH) to produce a red color
    • Evaluation or Estimation:
      • Methods used: gravimetric and colourimetric
      • Aglycones are isolated according to Borntrager's reaction, and the intensity of the alkaline solution is measured in a colorimeter using 1,8-dihydroxyanthraquinone as a standard

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    Description

    This quiz covers the classification of anthracene glycosides, a group of glycosides with anthracene derivatives as aglycones. Learn about the different types, including anthraquinone derivatives, anthrones and anthronols, dianthrone and dianthranol, and oxanthrone.

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