Ausbeutebestimmende Einflussfaktoren bei der Extraktion von Flavonoiden aus Pflanzenblättern

  • Yield determining parameters in natural plant extraction of flavonoids from plant leaves

Lück, Manuel; Jupke, Andreas (Thesis advisor); Usadel, Björn (Thesis advisor)

Aachen : RWTH Aachen University (2021, 2022)
Dissertation / PhD Thesis

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2021


Higher plants synthesize a variety of high value secondary metabolites that can also be beneficial for human health. The quantitative analysis of the target compound is a key aspect for both analytical and preparative extraction processes for designing effective processes. Previous approaches have described the extraction by mechanisms such as diffusion or adsorption, but have taken little account of botanical factors. Specifically, these are the structure of the plant matrix, the chemical structure of target and side compounds as well as the localization of these substances. The aim of this work is to highlight the influence of botanical aspects on the achievable extraction yield using the example of the extraction of the flavonoid rutin from tomato leaves. The aspects phase equilibria, choice of solvent, particle size, accessibility and influence of side compounds are systematically analyzed in order to explain the phenomena of extraction through their basic mechanisms. The central observation is that the amount of solvent has a significant influence on the extraction yield. However, no thermodynamic phase equilibrium is detectable and the solvent strength also has only a minor influence on the extraction yield. Rather, the yield is influenced by an accessibility limitation, which is shown by the significant influence of the particle size. The side compounds in the cell interior, especially membrane lipids, also play an important role in restricting the accessibility of the target compound. These can cover the target compound in the plant material and thus limit the accessibility of the solvent. Sufficient extraction of the side compounds is therefore necessary in order to achieve a high yield of the target compound. The phenomena observed here can be transferred to the plant systems buckwheat herb, pagoda tree buds and bell pepper leaves and thus represent important findings for future analytical extraction tasks and developments of preparative processes.