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

monosaccharides on hydrolysis by acids; namely, D-glucose, D-galactose, D-

mannose, D-xylose and L-arabinose.

2) Acidic hemicellulose (-Cellulose): “hemicellulose containing uronic acids”

They are amorphous polysaccharide deposited together with lignin of the

cell wall. They contain uronic acid moieties and referred as polyuronide

hemicellulose. By acid hydrolysis, they give sugar and uronic acid. The molecule

may conation either:

a) D-Glucuronic acid and D-xylose

b) D-Galacturonic acid and L-Arabinose.

Functions in plant:

1) As reserve food material. 2) As plasticizer.

II- Plant Gums

They are essentially polysaccharides containing hexuronic acid residues, in

salt form, and a number of neutral monosaccharide units, which are often

esterified in highly branched structures. These gums may be formed

spontaneously or may be induced by deliberately cutting the bark or fruit. They

are exuded as viscous liquids which become hard nodules on dehydration to seal

the site of injury and so provide protection from micro-organisms.

Glucose is absent from plant gums. They can be regarded as almost

neutral salts of complex polysaccharide acids containing methylpentose,

pentose, hexose and uronic acid residues jointed glycosidically to form branched

chain. These are:

▪ Methyl-pentoses: L-Rhamnose, L-Fucose.
▪ Pentoses: D-Xylose, L-Arabinose

▪ Hexoses: D-Mannose, D-Galactose.
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