Skip to main content

Renin Angiotensin Mechanism.

Chemical Nature of crude Drugs: Tannins.

TANNINS



  • Chemically tannins are derivatives of polyhydroxy benzoic acid, capable of combining with proteins. They are complex, high molecular Wt. Organic nitrogenous substances.

  • They are non- crystallizable, soluble in alcohol & water

  • 1. They have tanning property.

  • 2. They precipitate proteins and alkaloids.

  • 3. They are acidic in nature.

  • 4. They have an astringent test.

  • 5. They cause the contraction of smooth muscle.

  • 6. They give dark blue, green black color with ferric salt or iron.

  • 7. They give the Goldbeater skin Test positive.

  • 8. They prevent putrification of leather.


Classification: -

  1. Hydrolysable. 2. Condensed.
Hydrolysable tannins
Condensed tannins
They are hydrolysable by acids or enzymes
They are more resistant to hydrolysis
Chemically they are esters of Phenolic acids
They are related to flavonoid pigments.
On treatment with acids or enzymes they produce Gallic acid or Ellagic acids.
On treatment with acids or enzymes, they decompose into insoluble red compound known as phlobaphenes
On dry distillation they are converted into pyrogallols
On dry distillation they produce catechol
With iron salts they produce blue colors.
With iron salts they produce green colors.
Ex. Clove, Myrobalon
Black catechu, Acacia bark.





















Chemical Test of Tannins: -

1) Gold beater’s skin Test: - Goldbeater skin is a membrane prepared from intestine of ox.

Gold beaters skin is treated with 2 % HCl. Wash the skin with water & keep the skin in the test solution for 5 minute. Again wash the skin with water. Treat the skin with 1 % FesO4 soln

If true tannins are present brown or black spot is produced on the skin.

2) Gelatin Test: - If solution of tannin is added to 1 % solution of gelatin containing 10 % NaCl, ppt. is produced.

3) Aqueous solution of tannins + Aq. solution of ferric chloride.

Hydrolysable tannin gives blue black colors & condensed tannin gives brownish green colors

4) Tannins give red color with vanillin hydrochloride reagent.

Isolation of Tannins (extraction): -



  • Raw material------ >Extract with ether + alcohol------> Filter ---->Shake Filtrate with water----------->Aqueous solution Takes most of tannin------->Evaporate aqueous extract to dryness under vacuum.

  • Crude Tannin dissolves in alcohol----- > Alcoholic solution id shaken with ether-------> Ppt of pure product is obtained from ether solution.

Labels:

Popular posts from this blog

Heat Exchangers and Heat Interchangers.

  In pharmaceutical industries many types of equipments are used for transfer of heat, they can be classified as follows, Heat Exchangers. Heat Interchangers. Heat Exchangers: These devices are used for transferring heat from a fluid (Hot Gas or Steam) to another fluid (Liquid) through a metal wall. Heat Interchangers: These devices are used for transferring heat from a One liquid to another liquid or one gas to another gas through a metal wall. HEAT EXCHANGERS; The equipment used for heat transferring are known as heat exchangers. Some of the processes that involves heat transfer in pharmaceutical industries are: Preparation of starch paste (in steam jacketed kettle). Crystallization. Evaporation. Distillation.  Classification of heat exchangers On the basis of transfer of heat, heat exchangers are classified as: Direct transfer type:  The hot and cold fluids are separated by a metal wall through which the heat is transferred from hot fluid to cold fluid. E.g. shell and ...
Read more

Glycogenesis.

  Definition: Biosynthesis of Glycogen from Glucose is called Glycogenesis. Glycogen is synthesized  Depending on the demand for glucose and ATP (energy), insulin promotes the glucose conversion into glycogen. Glycogen is the major storage form of carbohydrate in animals similar to starch in plants. It is a homopolymer made up of repeated units of α- D glucose and each molecule is linked to another by 1→4 glycosidic bonds . Once there is a chain consisting of 8 to 10 glycosidic residues in the glycogen fragment, branching begins by 1→6 linkages . Glycogen is stored in liver and skeletal muscles. Location: Cytoplasm of cells in the muscle, liver, and adipose tissue. Steps Involved in Glycogenesis: Glucose is converted into glucose-6-phosphate by the action of glucokinase or hexokinase  with conversion of ATP to ADP. Glucose-6-phosphate is converted into glucose-1-phosphate by the action of phosphoglucomutase. Glucose-1-phosphate is converted into UDP-glucose by the actio...
Read more

Rate of Drying Curve.

  Definition Drying is defined as the removal of liquid from a product usually with application of heat. Rate of Drying Curve. Drying process can be divided into three periods Initial Adjustment Period. Constant drying rate period. First falling drying rate period. Second falling rate period. Initial Adjustment Period (A-B): Also called the “ Heating up” period . In this period the substance gets heat and increases in temperature. Drying has not yet started. Constant drying rate period (B-C): During this period the temperature of the solid and the rate of drying remain constant. The moisture evaporating from the surface is replaced by water diffusing from the interior of the solid at a rate equal t o the rate of evaporation.  The moisture content at the end of constant rate (point C) is referred to as the critical moisture content (CMC).  At CMC, dry spots start appearing and drying rate starts falling . First falling drying rate period (C-D): This period is also called ...
Read more