Page 28 - PG 504-theoretical notes-phyto-1-2024-2025..

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

B) Oligosaccharides:

• The molecules of this type contain 2 - 10 monosaccharide units, mostly of

hexoses. They are further classified according to the number of

monosaccharide units produced on hydrolysis:

1) Disaccharide:

They have the general molecular formula C 12H 22O 11. They are crystalline,

water soluble with sweet taste. On hydrolysis, they afford two monosaccharide

units, e.g., maltose, lactose sucrose.

Sucrose + H2O → Glucose + Fructose.

Maltose + H2O → Glucose + Glucose.

Lactose + H2O → Glucose + Galctose

2) Trisaccharides:

Yield on hydrolysis, three monosaccharide units, e.g., gentianose and raffinose.

Raffinose + 2 H2O → Galactose + Glucose + Fructose.

3) Tetrasaccharide: e.g., stachyose.

On hydrolysis → four monosaccharide units.

Stachyose + 3H2O → 2 Galactose + Glucose + Fructose.

4) Pentasaccharide: 5) Hexasaccharide:

• The di-, tri-, tetra-, penta- and hexasaccharides occur in nature and they can

be isolated also from the hydrolysis-products of polysaccharides.

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