[Highlight Lecture] – About the potential of plant senescence as a new source for drug discovery

Natural products have always been a major source of new lead structures and many of the traditionally applied herbal materials have been well characterised with regard to their phytochemistry. By now, the ongoing search for new drugs and chemical entities has reached exotic and remote organisms that lack traditional application and that are rather hard to supply. However, plant senescence might spotlight herbal materials again as a complementary source for drug discovery. While yet hardly explored, plant senescence appears to involve significant changes of the secondary plant metabolome that may result from the rearrangement of secondary metabolites in the course of nutrient reallocation and from the oxidative conditions in senescing tissue. Besides just quantitatively altering the metabolome, senescence processes in cherry laurel leaves have also proven to result in new natural products that are hardly detectable in green tissue and that allowed new insights on the main constituent's catabolism. The well-established technique of ethylene fumigation is capable of inducing the observed metabolic changes and therefore suggests a straightforward method for the biotechnological production of senescence-associated metabolites.

First studies indicate that the phytochemical differences may also impact on the bioactivity of senescent materials. Inclusion of senescent plant material to metabolomic studies aiming at the identification of bioactive constituents may therefore improve the predictive power of supervised multivariate statistical analysis by significantly increasing the variability of both chemical fingerprint and bioactivity data.