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Clinical pharmacy PharmD program Third level Phytochemistry-1 (PG-504)

C) Polysaccharides:

• They are tasteless, of high molecular weight; polymers of monosaccharides

of very complex nature.

• On hydrolysis, they give several molecules of monosaccharide

(C6H10O5) n + n H2O → n C6H12O6 (n > 10)

• The number (n) is usually ranging from 100 - 2000 according to source.

• They are from plant origin such as cellulose, starch, pectin.... etc. as well as

from animal origin such as glycogen.

• They are either linear or branched in structure.

• They do not exhibit any of the properties of aldehyde or ketone group.

• They can be further classified into:

1) Homopolysaccharide:

o They are polymers of one type of monosaccharide; e.g., starch, cellulose.

o Starch yields on hydrolysis only glucose and can be classified as glucan.

2) Heteropolysaccharide:

o They yield more than one sugar on hydrolysis; e.g., glucomannan (glucose

and mannose), and named according to the sugars obtained.

3) Derived carbohydrates:

o In addition to the monosaccharide units, they yield on hydrolysis one or

more of:

a) Monosaccharide sulfate ester.

b) Uronic acid or acids.

c) Amino-sugar.

E.g: gums, Pectin, mucilages

The polysaccharides may be also classified according to the class of the

monosaccharide yielded on hydrolysis:
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