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VI. Chemo-taxonomical classification

In this system, equal importance is given for taxonomical status and
chemical constituents. There are certain types of chemical constituents
which are characteristic for certain classes of plants.
Primary metabolites are of universal occurrence and hence play little role
in chemo-taxonomical classification. Secondary metabolites of medicinal
value such as alkaloids and glycosides are important in this classification
method (restricted occurrence).
e.g. Tropane alkaloids generally occur in most of members of family
Solanaceae.
e.g. volatile oils occur in the members of Umbelliferae and Rutaceae.

Chemo-taxonomical classification Advantages
 Combine the advantages of chemical and taxonomical systems.
 Implies the therapeutic significance of crude drugs.

Chemo-taxonomical classification Disadvantages
 Failed to recognize the organized/unorganized nature of crude drugs.
 Not necessarily applicable in all cases.

Ergastic cell contents

They are non-living substances present in the cell (found in cytoplasm and
vacuole). They can be identified in plants by microscopical examination or
by chemical and physical tests. They include primary and secondary
metabolites.

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