The study of plant natural products can be considered to have started in
1806 when Serturner isolated the first of these compounds, morphine,
from the opium poppy. Over the next 150 years, numerous elegant and
powerful techniques were developed for the isolation and structural
identifi- cation of a variety of classes of these substances. With
increasing knowledge, various speculations were put forward on the ways
that these compounds were synthesised from pri- mary metabolites and on
their possible physiological, ecolo- gical and taxonomic importance.
These investigations sublimated in the late 1940's with the newly
developed application of radioactively labelled precursors to the study
vari ous bi osyntheti c pathways and use of rapid chromatagraphic and
spectroscopic methods to uncover the structure of a plethora of new
compounds and to their wide distribution in various taxa of plants
recognize and other organisms. We have now entered a new stage in our
investigation of natural products in which several important new
problems are being tackled. The present emphasis is on how the various
biosynthetic pathways are regulated, the enzymic parameters which
determine the chirality of the products, the transfer and modification
of components in food chains, and the ways in which a given class of
physiologically or ecologically important compounds has been superseded
by another during the course of evolution.