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Questions and Answers
What is a primary characteristic of hydrolysable tannins?
What is a primary characteristic of hydrolysable tannins?
Which term is alternatively used for condensed tannins?
Which term is alternatively used for condensed tannins?
What color do condensed tannins produce when tested with ferric chloride?
What color do condensed tannins produce when tested with ferric chloride?
What product is formed when condensed tannins are treated with acids or enzymes?
What product is formed when condensed tannins are treated with acids or enzymes?
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Which families of plants are known to be rich in both hydrolysable and condensed tannins?
Which families of plants are known to be rich in both hydrolysable and condensed tannins?
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What are pseudotannins characterized by?
What are pseudotannins characterized by?
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What is one of the protective functions of tannins in plants?
What is one of the protective functions of tannins in plants?
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Which of the following is NOT a characteristic of tannins?
Which of the following is NOT a characteristic of tannins?
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What distinguishes true tannins from pseudotannins in the context of the Goldbeater’s skin test?
What distinguishes true tannins from pseudotannins in the context of the Goldbeater’s skin test?
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Which of the following best describes hydrolysable tannins?
Which of the following best describes hydrolysable tannins?
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How are gallotannins classified under hydrolysable tannins?
How are gallotannins classified under hydrolysable tannins?
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What is the role of the mineral acids in the classification of tannins?
What is the role of the mineral acids in the classification of tannins?
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Which of the following statements correctly describes condensed tannins?
Which of the following statements correctly describes condensed tannins?
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What is one characteristic of high molecular weight compounds typically associated with true tannins?
What is one characteristic of high molecular weight compounds typically associated with true tannins?
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Which of these acids is not mentioned as a component of hydrolysable tannins?
Which of these acids is not mentioned as a component of hydrolysable tannins?
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Which process can help to categorize tannins based on their structure?
Which process can help to categorize tannins based on their structure?
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What does a positive Goldbeater's skin test indicate?
What does a positive Goldbeater's skin test indicate?
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Which test involves the use of sodium acid phosphate and phenazone to detect tannins?
Which test involves the use of sodium acid phosphate and phenazone to detect tannins?
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In the gelatin test, what causes the precipitation of gelatin?
In the gelatin test, what causes the precipitation of gelatin?
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The Matchstick Test detects catechin by indicating the presence of which compound?
The Matchstick Test detects catechin by indicating the presence of which compound?
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Which plant sources are known to contain significant amounts of tannins?
Which plant sources are known to contain significant amounts of tannins?
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What color change indicates the presence of chlorogenic acid in a sample?
What color change indicates the presence of chlorogenic acid in a sample?
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What forms as a result of the Vanillin-hydrochloric acid test when tannins are present?
What forms as a result of the Vanillin-hydrochloric acid test when tannins are present?
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Which of the following statements about pseudotannins is accurate?
Which of the following statements about pseudotannins is accurate?
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In which regions is U.gambier primarily cultivated?
In which regions is U.gambier primarily cultivated?
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What is the maximum yield of U.gambier typically obtained?
What is the maximum yield of U.gambier typically obtained?
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What is the primary method of propagation for U.gambier?
What is the primary method of propagation for U.gambier?
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What temperature is used for boiling the leaves and twigs of U.gambier during processing?
What temperature is used for boiling the leaves and twigs of U.gambier during processing?
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Which component constitutes over 60% of the drug derived from U.gambier?
Which component constitutes over 60% of the drug derived from U.gambier?
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What percentage of indole alkaloid can be found in U.gambier?
What percentage of indole alkaloid can be found in U.gambier?
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What is the final state of the extract after the drying process?
What is the final state of the extract after the drying process?
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Which of the following components is associated with fluorescence under UV light in U.gambier?
Which of the following components is associated with fluorescence under UV light in U.gambier?
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Which solvents are tannins soluble in?
Which solvents are tannins soluble in?
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What do tannins form when they bind with proteins?
What do tannins form when they bind with proteins?
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What is the molecular weight range of tannins?
What is the molecular weight range of tannins?
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Which structure is tannins vastly known to contain?
Which structure is tannins vastly known to contain?
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What is a pharmacological activity associated with tannins?
What is a pharmacological activity associated with tannins?
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Which of the following phenolic compounds is involved in the formation of tannins?
Which of the following phenolic compounds is involved in the formation of tannins?
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Which statement is true about hydrolysable and condensed tannins?
Which statement is true about hydrolysable and condensed tannins?
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Which of the following is NOT a test for the presence of tannins?
Which of the following is NOT a test for the presence of tannins?
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What enzyme is capable of hydrolyzing tannins?
What enzyme is capable of hydrolyzing tannins?
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How are proanthocyanidins (PAs) formed?
How are proanthocyanidins (PAs) formed?
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What is a common method for the extraction of tannic acid?
What is a common method for the extraction of tannic acid?
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Hydrolysable tannins are also known as what?
Hydrolysable tannins are also known as what?
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Which term is NOT synonymous with Condensed Tannins?
Which term is NOT synonymous with Condensed Tannins?
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A Flavan-3-ol condensed tannin is commonly referred to as?
A Flavan-3-ol condensed tannin is commonly referred to as?
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What characteristic does NOT typically apply to tannins?
What characteristic does NOT typically apply to tannins?
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Study Notes
Tannins
- Tannins are complex organic plant compounds with astringent properties, derived from the French word "tanin"
- They are widespread in the plant kingdom
- Early use of tannins was for tanning animal hides to leather (tanning)
- Tannins combine with animal hides through a test called Goldbeater's skin test
- Two major groups of tannins:
- Hydrolysable tannins: Hydrolyzed by minerals/enzymes, contain phenolic acids (gallic/ellagic) linked to a central glucose molecule
- The phenolic acids are important to their further classification
- Soluble in water; blue color with ferric chloride
- Condensed tannins (proanthocyanidins): Not readily hydrolyzed; contain only phenolic nuclei related to flavonoids
- Catechin and leucoanthocyanidins are examples of the phenolic compound in condensed tannins
- Produce insoluble red coloured products (phlobaphens) when treated with acids/enzymes
- Soluble in water but produce green color with ferric chloride
- Hydrolysable tannins: Hydrolyzed by minerals/enzymes, contain phenolic acids (gallic/ellagic) linked to a central glucose molecule
Pseudotannins
- Simple phenolic compounds with low molecular weight, do not react in the Goldbeater's skin test
- Examples include gallic acid, chlorogenic acid, and catechin
Tannin Characteristics
- Colloidal solutions in water (some high MW exceptions)
- Insoluble in organic solvents (except acetone)
- Soluble in alcohols, dilute alkali, and glycerin
Crude Drugs Containing Tannins
- Nutgalls from the plant Quercus infectoria: A pathological outgrowth on twigs of oak tree; important source for tannic acid (gallotannic acid)
- Collected in Turkey, Syria, etc.
- Pale Catechu (Gambier): Dried water extract of leaves and twigs of Uncaria gambier tree (Rubiaceae family)
- Native to Southeast Asia
- Black Catechu (Cutch): Dried extract of the heartwood of Acacia catechu:
- (Leguminosae family), distributed throughout India
- Other plants are known to contain tannins, including parts of some fruits and leaves
Tannin Uses
- Tanning leather
- Dyeing materials (e.g., fabrics)
- Pharmaceuticals (as astringents)
- Manufacturing inks, sizing paper, and similar products
- Various other uses including medicine & clarification of beer/wine
- Can bind to proteins, forming soluble or insoluble tannin-protein complexes
Additional Tests
- Goldbeater's skin test: Identifies true tannins by their ability to tan the membrane
- Phenazone test, Gelatin Test, Catechin test (Matchstick Test) & Vanillin-hydrochloric acid test
can be used to further ascertain the presence of different types of tannins
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Description
Explore the fascinating world of tannins, complex organic compounds found in plants. Learn about their astringent properties, major groups, and significance in processes like tanning animal hides. This quiz delves into hydrolysable and condensed tannins, highlighting their chemical structures and reactions.
