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... Show moreThe 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. Show less
Natural deep eutectic solvents (NADES) ionic liquids (ILs) and deep eutectic solvents (DES) were proposed by our group to extend the range of ILs and DES, particularly to develop cheap, nontoxic,... Show moreNatural deep eutectic solvents (NADES) ionic liquids (ILs) and deep eutectic solvents (DES) were proposed by our group to extend the range of ILs and DES, particularly to develop cheap, nontoxic, and low viscosity green solvents, and to apply them in health-related fields. They are liquid supramolecules composed of common metabolites in certain molar ratios, including some water in some cases, which are characterized by extensive intermolecular interactions e.g. hydrogen bonds and ionic bonds. NADES present many advantages including low cost, simple preparation, low or negligible toxicity profile and sustainability in view of environment and economics benefits. Their preparation methods, physicochemical properties, supramolecules structures are reported in this thesis. For application, compare to conventional solvents, they show higher solubilization and extraction ability, especially for non-water soluble compounds. They are stable liquids even below zero oC, and their physicochemical properties can be adjusted by changing the water content. In the presence of NADES, anthocyanins and phenolic compounds such as carthamin show higher stability. In addition, we hypothesize that NADES might be involved in the biosynthesis, storage, and transport of various non-water soluble metabolites in cells. In-vitro evidences for their possible functions are also explored in this thesis. Show less
