Abstract
Plants have always been used as medicines since ancient times to treat diseases. The
knowledge around the active components of herbal preparations has remained nevertheless
fragmentary: the biosynthetic pathways of many secondary metabolites of pharmacological
importance have been clarified only in a few species, while the chemodiversity present
in many medicinal plants has remained largely unexplored. Despite the advancements
of synthetic biology for production of medicinal compounds in heterologous hosts,
the native plant species are often the most reliable and economic source for their
production. It thus becomes fundamental to investigate the metabolic composition of
medicinal plants to characterize their natural metabolic diversity and to define the
biosynthetic routes in planta of important compounds to develop strategies to further increase their content. We
present here a number of case studies for selected classes of secondary metabolites
and we review their health benefits and the historical developments in their structural
elucidation and characterization of biosynthetic genes. We cover the cases of benzoisoquinoline
and monoterpenoid indole alkaloids, cannabinoids, caffeine, ginsenosides, withanolides,
artemisinin, and taxol; we show how the “early” biochemical or the more recent integrative
approaches–based on omics-analyses–have helped to elucidate their metabolic pathways
and cellular compartmentation. We also summarize how the knowledge generated about
their biosynthesis has been used to develop metabolic engineering strategies in heterologous
and native hosts. We conclude that following the advent of novel, high-throughput
and cost-effective analytical technologies, the secondary metabolism of medicinal
plants can now be examined under the lens of systems biology.
Key words
Papaver somniferum
- Papaveraceae -
Catharanthus roseus
- Apocynaceae - alkaloids - caffeine - cannabinoids - ginseng - artemisinin - taxol
