tannins Flashcards

1
Q

this term was first applied by Seguin in 1796 to denote substances present in plant extracts which were able to combine with protein of animal hides, prevent their putrefaction and convert them into leather.

A

TANNINS

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2
Q

Tannins Is a substance which is detected qualitatively by ___

A

Tannin Test (Goldbeater’s Skin Test)

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3
Q

Tannins Is a substance which is determined quantitatively by its

A

absorption on standard hide powder.

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4
Q

T OR F
Only a few tannins are glycosides

A

FALSE

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5
Q

Tannins are source of fruit acids. Enumerate.

A

Glycolic
Lactic
Mandelic
Malic
Tartaric
Citric acid

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6
Q

T OR F
Tannins are found in mature fruits.

A

False

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7
Q

Tannins are found in specific plant parts. Enumerate.

A

Leaves
Fruits
Barks
Stems

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8
Q

Are Found in great quantities in dead or drying cells.

Occur in solution in cell sap, often in distinct vacuoles.

A

Tannins

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9
Q

a mixture of polyphenols and non-crystallizable compounds

A

Complex Substance

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10
Q

This may be hydrolyzed by acids or enzymes such as Tannase.

A

Hydrolysable Tannins

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11
Q

Hydrolysable Tannins may be hydrolyzed by acids or enzymes such as ____.

A

Tannase

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12
Q

They form several molecules of phenolic acids as Gallic acid and Hexahydroxy-diphenic acid which are united by ester linkages to a central glucose molecules.

A

Hydrolysable Tannins

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13
Q

What are hydrolysable tannins formerly known as?

A

Pyrogallol Tannins

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14
Q

dry distillation, Gallic acid and similar components are converted to

A

Pyrogallol

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15
Q

Hydrolysable Tannins When treated with acids/enzymes

A

Phenolic Acids (Gallic Acid, Ellagic Acid, Glucose)

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16
Q

Gallitannins

A

Gallic Acid

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17
Q

Ellagitannins

A

Hexahydroxy-diphenic acid units

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18
Q

Ferric Chloride (Hydrolysable Tannins)

A

Blue Color

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19
Q

Bromides (Hydrolysable Tannins)

A

No precipitate

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20
Q

Condensed Tannins (Proanthocyanidins, Polyflavonoid, Catechol-type, Pyrocatecollic-type tannins)

A

Non-Hydrolysable Tannins

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21
Q

Are not readily hydrolyzed to simpler molecules and they do not contain a sugar moiety.

A

Non-Hydrolysable Tannins

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22
Q

Are related to the Flavonoid pigments and have polymeric Flavan-3-ol structures.

A

Non-Hydrolysable Tannins

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23
Q

Catechins which also occur with the tannins and Flavan in the biosynthesis of the molecules.

A

Non-Hydrolysable Tannins

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24
Q

Non-Hydrolysable Tannins When treated with acids/enzymes

A

converted into red insoluble compounds known as Phlobaphenes

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25
Q

It gives the characteristic color to many drugs (red cinchona bark)

A

Phlobaphenes

26
Q

Non-Hydrolysable Tannins when subjected to dry distillation

A

Catechols called as Catechol Tannins

27
Q

Ferric Chloride (Non-Hydrolysable Tannins)

A

Greenish

28
Q

Bromides (Non-Hydrolysable Tannins)

A

Precipitate

29
Q

Are compounds of lower molecular weight than true tannins and they do not respond to the Goldbeater’s skin test

A

Pseudotannins

30
Q

Pseudotannins are Formed by either linkages between two or more molecules of Phenolic acid:

A

Digallic and Chlorogenic Acid

31
Q

Pseudotannins And others are derivatives of Flavan

A

Catechins/Catechols

32
Q

Pseudotannins
Example - Gallic Acid:

A

Rhubarb and most materials which contains gallitannins

33
Q

Pseudotannins
Examples - Catechins:

A

Catechu, Acacia cutch, Kino, Cocoa, Guarana

34
Q

Pseudotannins
Examples - Chlorogenic acid:

A

Unroasted coffee, Nux vomica

35
Q

Pseudotannins
Examples - Ipecacuanha acid:

A

Ipecacuanha

36
Q

Pyrocatechol/Phlobatannins
▪Heated -

A

Catechol

37
Q

Pyrocatechol/Phlobatannins
▪Boiled with HCl -

A

Insoluble Red Phlobaphenes

38
Q

Pyrocatechol/Phlobatannins
Treated with FeCl3 T.S. -

A

Green Color

39
Q

Pyrocatechol/Phlobatannins
▪Treated with Bromine T.S. -

A

Formed Precipitate

40
Q

Pyrocatechol/Phlobatannins Examples

A

Kino
Gambir

41
Q

Pyrogallol Tannins
▪ Heated

A

Pyrogallol

42
Q

Pyrogallol Tannins
▪ Boiled with HCl -

A

Gallic Acid/Ellagic Acid

43
Q

Pyrogallol Tannins
▪ Treated with FeCl3 T.S. -

A

Blue Color

44
Q

Pyrogallol Tannins
▪ Treated with Bromine T.S.

A

No Precipitate

45
Q

Pyrogallol Tannins Examples

A

Nut gall
Oak Bark
Pomegranate Bark

46
Q

Tannins Uses

A
  • Antiseptic
    ❑ Astringent
    ❑ Antidote for Alkaloidal poisoning
    ❑ Preservative on leather
    ❑ Laboratory reagent for protein and alkaloid identification.
    ❑ Ink industries
47
Q

Antioxidants

A
  • Leucoanthocyanidins
    ▪ Proanthocyanidins
    ▪ Pycnogenol
48
Q

Improves peripheral circulation, capillary fragility, retinophaties, inflammatory collagen disease

A

Grape Seeds - Vitis vinifera
Needles and Barks of Pine Tree - Pinus pinaster

49
Q

Tests for Tannins

A
  • Solubility
    ❑ Reaction with Ferric Salts
    ❑ Goldbeater’s Skin Test
    ❑ Phenazone Test
    ❑ Gelatin Test
    ❑ Test for Catechin
    ❑ Test for Chlorogenic Acid
50
Q

Plants with Rich Sources of Tannins in Flowers

A

Lime
Hawthorn

51
Q

Plants with Rich Sources of Tannins in Fruits

A

Cranberry
Grapes
Hawthorn

52
Q

Plants with Rich Sources of Tannins in Seeds

A

Areca
Cacao
Guarana
Kola

53
Q

Plants with Rich Sources of Tannins in Leaves

A

Hamamelis
Hawthorn

54
Q

Plants with Rich Sources of Tannins in Barks

A

Acacia
Cinnamon
Hamamelis
Oak
Willow
Wild Cherry

55
Q

Plants with Rich Sources of Tannins in Roots and Rizomes

A

Krameria
Male Fern

56
Q

Plants with Rich Sources of Tannins in Extracts and Dried Juices

A

Butea Gum
Acacia Catechu
Mangrove
East Indian Kino
Eucalyptus Kino

57
Q

High rates of oral esophageal cancer in India and South Africa.

A

Habitual Chewing of Betel Nut

58
Q

Lower incidence of esophageal cancer in British than Dutch.

A

Drinking of Ordinary Tea

59
Q

TANNIN-RICH PLANT FAMILIES

A

❑ Combretaceae - Quisqualis
❑ Geraniaceae - Geraniums
❑ Leguminosae – Acacia, Tamarind
❑ Myrtaceae – Eucalyptus, Guava
❑ Polygonaceae – Buckwheat
❑ Rosaceae – Red rose
❑ Rubiaceae – Gambir
❑ Theaceae – Tea

60
Q

❑ Plant polyphenols
❑ “Tannin Extracts”
❑ Non-crystallizable

A

Tannins

61
Q

❑ Precipitate proteins
❑ Sharp “puckering” taste

A

Tannins