Page 105 - Pharmd general phytochemistry I-Final2024_LEUCTERS

Configuration:
 The open chain structures of sugars was proposed by Fisher in 1880's, while in

1926 Howarth proposed the cyclic structure (pyranose and furanose rings).
 The configuration of sugars is designated by the symbols D & L.
 Monosaccharides are designated as D & L on the basis of the configuration of the

highest numbered asymmetric carbon, D if the -OH is on the right and L if the -OH
is on the left.
 The symbols d and I or (+) and (-) are used to designate sign of rotation of plane-
polarized light.
 Monosaccharides existing in the form of heterocycles are classified with respect to
the size of the ring system i.e. 6-membered ring structures considered to be related
to pyran are called pyranoses, and the 5 -membered ring structures related to furan
are called furanoses. This type of nomenclature can be applied to oligosaccharides
and glycoside derivatives, e.g. maltose can be named 4-D-glucopyranose-α-D-
glucopyranoside, sucrose is 1-α D-glucopyranosyl-β-D-fructofuranoside, and
lactose is 4-D- glucopyranosyl-β-D-galactopyranoside.

Carbohydrates of Medicinal and Pharmaceutical
Importance

 Many pharmaceutical products contain carbohydrates and their derivatives as
therapeutic agents or as pharmaceutic necessities.

Sugar alcohols

 These compounds are closely related to carbohydrates, so it is traditional to
classify them as carbohydrate derivatives, i.e. sugar alcohols

 The hexahydroxy alcohols, sorbitol (glucitol), mannitol and galactitol (dulcitol) are
natural products widely distributed in plants, they are reduction products of the
corresponding aldohexoses, glucose, mannose and galactose, respectively.

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