ABSTRACT
Some plants are the source of several natural drugs and hence these plants are termed medicinal. These drugs are various types of secondary metabolites produced by plants and several are very important, as described in Chapter 2 of this book. Essentially, plant cells contain primary and secondary metabolites. Primary metabolites are substances widely distributed in nature, occurring in one form or another in virtually all organisms. In higher plants, these compounds accumulate in storage organs or seeds and are required for physiological development because of their role in basic cell metabolism.
