Page 7 - phytochemistry I - PharmD Clinical

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.

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