Phytochemical background matters for bioactivity of plant metabolites : a case study with pyrrolizidine alkaloids

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Phytochemical background matters for bioactivity of plant metabolites : a case study with pyrrolizidine alkaloids

Type: Doctoral Thesis
Title: Phytochemical background matters for bioactivity of plant metabolites : a case study with pyrrolizidine alkaloids
Author: Liu, X.
Issue Date: 2016-12-22
Keywords: Jacobaea
Extraction
Fractionation
Chlorogenic acid
Synergism
Antagonism
Thrips
Ames test
Plant defence
Mutagenicity
Abstract: The plant kingdom has evolved an enormous number of chemically diverse metabolites that protect plants from biotic and abiotic stresses. The large number of metabolites in a given plant indicates interactions between metabolites are very likely. The co-occurrence of plant metabolites comprise a natural background where these metabolites have to function and this is often overlooked or ignored in ecological studies. The main goal of this thesis is to understand the importance of metabolite interactions I used assays with a generalist herbivore to study the interactions between chlorogenic acid (CGA), pyrrolizidine alkaloids (PAs) and fractions from Jacobaea plants. I found that PA free bases, PA N-oxides (the oxidized form of free base) and CGA decreased thrips survival. Although PA free bases and CGA decreased thrips survival, the combination of the two toxins was less toxic than the single toxins. In contrast, the combination of PA N-oxides with CGA enhanced the toxicity against thrips in a synergistic way. Adding PAs to different plant fractions showed that metabolite interactions on thrips survival are common as in all tested combinations we found antagonistic and synergistic effects. Clearly, bioactivity of a metabolite is strongly dependent upon the co-occurrence of metabolites in the plant cell.
Promotor: Supervisor: P.G.L. Klinkhamer Co-Supervisor: K. Vrijdag, P.P.J. Mulder
Faculty: Science
University: Leiden
Uri: urn:isbn:9789462994973
Handle: http://hdl.handle.net/1887/45055
 

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