Page 102 - Pharmd general phytochemistry I-Final2024_LEUCTERS

CARBOHYDRATES

As the name implies, carbohydrates consist of carbon, hydrogen and oxygen with the

last two elements usually present in the same proportion as in water (deoxysugars,

sugar acids and amino sugars are exceptions).
 On a functional group basis, carbohydrates are polyhydroxy compounds

(aldehydes, ketones and their derivatives).
 Carbohydrates are extensively distributed in both the plant and animal kingdoms.

They serve as a source of energy for plants and animals, and in the form of

cellulose which function as the supporting structures of plants.

Classification of Carbohydrates

Carbohydrates are complex group of natural products. they can be broadly classified

as follows:
A) According to the number of monosaccharide units present in the molecule:

1. Simple Carbohydrates:

a. Monosaccharides:
1) Diose e.g.CH2OH-CHO.
2) Triose e.g. glyceraldehydes.
3) Tetrose e.g. Erythrose and Threose.
4) pentoses: e.g. xylose, arabinose and ribose ….etc.
5) Hexoses:

(a) Aldoses: (e.g.glucose , mannose and galactose)
(b) Ketoses: (e.g. Fructose).

b. Disaccharides:
1) Reducing disaccharides: e.g. lactose, maltose, and lactulose.

2) Non-reducing disaccharides: e.g. sucrose.

2. Polysaccharides:

1) Glucans: e.g. starch, amylose, amylopectin, glycogen, dextrin, cellulose &
dextran.
2) Fructosans: e.g. Inulin.
3) Galactans.
4) Pentosans: xylans,arabans, (gums) and, hemicellulose .
5) Polyuronides: pectins, alginic of mucilages.
6) Heteroglycans: Certain bacterial polysaccharides.

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