Page 108 - phytochemistry I - PharmD Clinical

Medicinal Glycosides
Introduction to glycosides:

Glycoside is a class of secondary metabolites having chemical and
medicinal importance. Glycosides are organic compounds that yield one
or more sugars upon hydrolysis. The term glycoside is a generic term for
natural product that is chemically bound to a sugar. Thus the glycoside
composes of two parts: the sugar (glycone) and the genin (aglycone). The
aglycone may be a terpene, a flavonoid, a coumarin or any other natural
product.

Glycoside showed extra chemical diversity. Among the sugars found in
natural glycosides, D-glucose is the most abundant one, L-rhamnose and
L-fructose also occurs quite frequently. Of the pentoses, L-arabinose is
more common than D-xylose. The sugar part can also be a disaccharide.

This chapter discusses the chemistry of naturally occurring glycosides
including molecular structures of the different classes of glycosides and
their stability. As well as general procedures of extraction, isolation and
purification of glycosides and methods of their analysis. In addition to
selected examples of glycosides and studying their sources and
identification tests. A closer insight into biologically active glycosides
concerning their pharmacokinetics, medicinal uses and their mechanisms
actions.

Occurrence and distribution:

Glycosides are widespread throughout living organisms and especially
the plant kingdom. They occur in higher plants as well as fungal and
bacterial cells and animals. In plants, they are mostly found in seeds,
underground roots or shoots, flowers and leaves. Mammalian glycosides
are simple compounds whereas plant glycosides are much larger and
more complex. Humans form glycosides in the liver as part of
detoxification process and they are excreted via urine.

۱۰٦