2 CLASSIFICATION
In reality, the most befitting classification of glycosides is rather a hard-nut-to-crack. In case, the classification is to be governed by the presence of sugar moiety, a good number of rare sugars are involved, if the aglycone function forms the basis of classification, one may come across groups from probably all major categories of plant constituents identified and reported. Of course, a therapeutic classification offers not only a positive edge over the stated classification but also affords an excellent means from a pharmaceutic viewpoint, but it grossly lacks a host of glycosides which are of great pharmacognostic interest.
The most acceptable classification of glycosides is based on the chemical nature of the aglycone moiety present in them, namely:
(i) Anthracene glycosides
(ii) Phenol glycosides
(iii) Steroid glycosides
(iv) Flavonoid glycosides
(v) Coumarin and Furanocoumarin glycosides
(vi) Cyonogenetic glycosides
(vii) Thioglycosides
(viii) Saponin glycosides
(ix) Aldehyde glycosides
(x) Bitter glycosides
(xi) Miscellaneous glycosides
All these different categories of glycosides would be discussed individually with appropriate examples in the sections that follows: