Glycosides Lecture (8)
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Questions and Answers

What is the main bitter component found in grapefruit juice?

  • Naringenin
  • Naringin (correct)
  • Liquiritin
  • Neohesperidose

    • What is the sweetness level of Naringin compared to sucrose?

  • Approximately equal to sucrose
  • 100 times sweeter than sucrose
  • 1000 times sweeter than sucrose (correct)
  • Not sweet at all

    • Which of the following describes a use of Liquiritin?

  • Boosting immunity
  • Anti-inflammatory and treating gastric ulcers (correct)
  • Treating respiratory infections
  • Weight loss supplement

    • Which sugar component is part of Naringin?

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

    What transformation can Naringin undergo with NaOH and H2/Pd?

    <p>Transforming into Naringin chalcone</p> Signup and view all the answers

    Which flavonoids are primarily known for their presence in green tea?

    <p>Epigallocatechin and its derivatives</p> Signup and view all the answers

    What is a primary medicinal use of procyanidins from Crataegus?

    <p>Treatment of heart diseases</p> Signup and view all the answers

    Which compound found in black tea is a type of flavonoid?

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

    Which compound is formed when Astilbin is treated with acid?

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

    What action is epicatechin primarily associated with?

    <p>Fat burning and slimming</p> Signup and view all the answers

    Which of the following is NOT a characteristic of proanthocyanidins?

    <p>They are readily soluble in water</p> Signup and view all the answers

    Which type of compound is classified as a dietary phytoestrogen?

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

    What is the significance of the structure of anthocyanidins in relation to pH?

    <p>They show color changes between acidic and alkaline conditions.</p> Signup and view all the answers

    Which flavonoid derivative is noted for its antiuremic action?

    <p>Epicatechin 3-O-gallate</p> Signup and view all the answers

    What is one of the pharmacological actions of (+)-Catechin?

    <p>Antioxidant properties</p> Signup and view all the answers

    Which of the following statements is true about Neoastilbin?

    <p>It is derived from Astilbin.</p> Signup and view all the answers

    Which of the following glycosides is primarily found in soya beans?

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

    Amentoflavone is primarily found in which plant?

    <p>Chrozophora sp.</p> Signup and view all the answers

    What is the primary function of anthocyanins?

    <p>They serve as antioxidants.</p> Signup and view all the answers

    Which of the following compounds is not classified as an isoflavonoid glycoside?

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

    What is a common use of isoflavonoid glycosides?

    <p>Preventing breast and prostate cancer</p> Signup and view all the answers

    What are the principal components of silymarin?

    <p>Silybin, Silychristin, and Silydianin</p> Signup and view all the answers

    Which of the following is NOT a pharmacological action of silymarin?

    <p>Enhancement of digestive enzyme release</p> Signup and view all the answers

    What problem does silybin face when taken orally?

    <p>Very poor bioavailability</p> Signup and view all the answers

    Which enhancement method is NOT mentioned for improving silybin's bioavailability?

    <p>Formation of microemulsions</p> Signup and view all the answers

    In which of the following conditions is silymarin commonly used?

    <p>Chronic degenerative liver conditions</p> Signup and view all the answers

    What is a significant benefit of forming complexes with phosphatidyl-choline?

    <p>Improved absorption in the gastrointestinal tract</p> Signup and view all the answers

    Which of the following components can be found in the fruits of Silybum marianum?

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

    Which of the following best describes the pharmacokinetic studies of silybin complexes?

    <p>Showed improved bioavailability, up to 10 times</p> Signup and view all the answers

    What compound is produced from alliin after crushing garlic?

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

    Which of the following describes the structure and function of cyano-glycosides?

    <p>O-glycosides that release HCN gas as a chemical defense mechanism</p> Signup and view all the answers

    Which compound is associated with both antibacterial and anti-hyperlipidemic properties?

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

    Amygdalin is primarily found in which of the following?

    <p>Bitter almond seeds</p> Signup and view all the answers

    What is the primary effect of dicoumarol in the human body?

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

    What enzyme converts alliin to allicin?

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

    Which of the following compounds is known for its hepatotoxic effects?

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

    What is released when amygdalin is hydrolyzed by emulsin?

    <p>Benzaldehyde and glucose</p> Signup and view all the answers

    Which of the following describes the role of glucosinolates?

    <p>Flavoring agents and chemical defenses in plants</p> Signup and view all the answers

    What is a primary characteristic of non-glycosidic organo-sulfur drugs?

    <p>They possess strong aromatic properties.</p> Signup and view all the answers

    What does Band I of the UV spectral absorption in flavonoids primarily correspond to?

    <p>Cinnamoyl system of ring B</p> Signup and view all the answers

    Which carotenoid layout can produce two UV absorption maxima?

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

    What range of wavelengths corresponds to Band II of flavonoid UV absorption?

    <p>220-280 nm</p> Signup and view all the answers

    What is a primary chemical characteristic of phenolic hydroxyl (OH) groups in flavonoids?

    <p>Increased solubility in water</p> Signup and view all the answers

    Which of the following flavonoid types does NOT exhibit a hydroxyl group linked to ring B?

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

    Which flavonoid glycoside is associated with increasing venous tone and treating capillary fragility?

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

    Which of the following mechanisms describes how diosmin affects the body?

    <p>Promotes vasodilation</p> Signup and view all the answers

    Which is a characteristic structural feature that distinguishes flavonoids from other compounds?

    <p>Presence of multiple benzene rings</p> Signup and view all the answers

    The UV-Vis absorption patterns are affected by what specific feature of flavonoids?

    <p>The substitution pattern on phenolic rings</p> Signup and view all the answers

    Which of the following compounds is correctly categorized under the flavonoid class?

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

    Study Notes

    Glycosides Lecture (8)

    • Phenolic Glycosides
      • Flavonoid glycosides (E)
      • Coumarin glycosides (F)
    • Non-glycosidic organo-sulfur drugs
    • Cyanogenic Glycosides
    • Glucosinolates

    E- Flavonoid Glycosides

    • A diverse group of natural products
    • Found in fruits, vegetables, nuts, seeds, stems, and flowers, as well as tea
    • Important constituents of the human diet
    • Often found free or in glycosidic form, more often in higher plants
    • Common in the seeds of Leguminosae family (isoflavonoids) and Polygonaceae family (flavan-3-ols, anthocyanins)
    • Skeleton: Diphenyl propane derivatives; 15 carbons

    Role in Plant Defense and Other Functions

    • Limited role in plant defense mechanisms.
    • Production of phytoalexins (isoflavones or isoflavanones) or other plant phenolics in response to fungal infections or external stimuli.
    • Pigments in flowers attract pollinating birds and insects.
    • Plant growth regulators, inhibiting or activating enzymes.

    Pharmacological Activities

    • Binding to enzymes and cell membranes
    • Chelation of heavy metal ions
    • Electron transfer in enzyme systems, e.g., oxidoreductases
    • Free radical scavenging (antioxidant)

    Therapeutic Uses

    • Procyanidins in Crateagus sp.: Cardiotonic
    • Catechins in Tea: Anticancer
    • Flavonoids in Licorice: Antiviral
    • Daidzin & Genistin in Soybeans: Anticancer
    • Rutin in Citrus: Prevent capillary fragility
    • Flavonoids in Buchu: Diuretic
    • Tinctormine in Safflower: Treat angina ("Ca antagonist")
    • Astilbin in Smilax: Anti-hepatotoxic
    • Silybin in Silybum marianum: Anti-hepatotoxic

    Identification Methods

    • Reaction with AlCl3: Yellow color
    • Shinoda's Test: Orange, red, or violet color using Mg metal/HCl in alcoholic solution
    • Lead Subacetate Test: Yellow precipitate on addition of lead subacetate to an alcoholic solution.
    • UV Spectral Absorption: Flavonoids show two absorption maxima:
      • Band I (220-280nm): Due to cinnamoyl system of ring B + C4=O
      • Band II (300-400nm): Due to benzoyl system of ring A + C4=O
    • Hydroxylation Pattern: Phenolic OH groups affect hydrophilicity, acidity, UV & visible light absorption, and chemical reactivity.

    Flavone Glycosides

    • Apiin: In celery and parsley leaves & seeds. Used for veins & hemorrhoids
    • Diosmin: In Buchu and other leaves. MOA treatment of capillary fragility and increase venous tone. Used prophylactially in varicose veins and acute hemorrhoids.

    Rutin (Flavonol Glycoside)

    • Hydrolysis: Rutin + 1N H2SO4 → Quercetin + Glc + Rh
    • MOA: Prevents capillary fragility, permeability and bleeding; strengthens capillaries.
    • Uses: Antioxidant, anti-inflammatory; treatment of varicose veins, hemorrhoids, internal bleeding

    F- Coumarins

    • Derivatives of benzo-α-pyrone or lactones of o-hydroxycinnamic acid.
    • Some are glycosidic, classified as phenolics
    • Some are toxic (e.g., aflatoxins) or have antibiotic properties (e.g., coumermycin).
    • Some have a strong odor and are bitter. They are soluble in alcohol.

    Coumarin Glycosides

    • Aesculin: Aesculus and Fraxinus species.
    • Uses: Treatment of varicose veins and hemorrhoids

    Coumarin Derivatives of Pharmaceutical Importance

    • 4-Hydroxycoumarins: (e.g., Bishydroxycoumarin): Anticoagulants.
    • Coumarin Antibiotics: (e.g., Novobiocin): Antibiotic agents.

    Poisonous Coumarins

    • Substances produced by fungi (e.g., Aflatoxins)
    • Hepatotoxic or carcinogenic.

    Non-glycosidic Organo-sulfur Drugs

    • Alliin: (+)-S-allyl-L-cysteine sulfoxide in fresh garlic.
    • Allicin: Diallyl thiosulfinate formed by alliinase enzyme after crushing garlic; Gives garlic its strong smell
    • Uses: Antimicrobial and anti-hyperlipidemic
    • Allicin+water: Diallyl disulfide, trisulfide, poly…

    Cyanogenic Glycosides

    • Plants contain these as flavoring agents; toxic.
    • Considered O-glycosides on H.OH
    • Plants use these compounds as a chemical defense (damaging/feeding)
    • Release HCN; toxic

    Amygdalin

    • Found in bitter almond seeds, apricots, peaches, plums
    • H.OH by emulsin → Benzaldehyde + HCN

    Glucosinolates

    • (Thioglycosides or Isothiocyanate glycosides) found in mustard family.
    • Sources include mustard seeds, rapeseed, horseradish, and cruciferous vegetables like broccoli and cabbage.
    • Pharmacological Action & Uses: Anticarcinogenic; externally, rubefacients; commercially, condiments.

    Isoflavonoid Glycosides

    • Daidzin & Genistin: Dietary phytoestrogens; prevent breast/prostate cancer; aid in osteoporosis treatment.

    Anthocyanidins

    • Natural coloured compounds dependent on pH (blue in alkaline, red in acidic).
    • Major examples Include pelargonidin, cyanidin and delphinidin.
    • Sugar part attached to C3.

    Flavon-3-ols

    • Catechin, epicatechin, epigallocatechin found in tea, rhubarb, and hawthorn.
    • Proanthocyanidins (flavanoids): Polymers of catechin & epicatechin
    • Uses: Antioxidants, lipid oxidation (slimming), anticancer, antiviral, antibacterial

    Biflavones

    • Amentoflavones: Located in Amentotaxus and Chrozophora.
    • Uses: Cardiotonic; prevents cataract formation in diabetic patients

    Flavonoid-containing Compounds

    • Silymarin: (Silybin, Silychristin, Silydianin) in milk thistle.
    • Uses: Hepatoprotective; prophylactic against toxins, liver dysfunction, hepatitis, and liver conditions

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    Glycosides Lecture Notes (PDF)

    Description

    Explore the fascinating world of glycosides in this lecture, focusing on phenolic glycosides, their roles in plant defense, and their importance in the human diet. Learn about various types such as flavonoid glycosides and glucosinolates, and discover their pharmacological activities.

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