[Thesis defence] 7 July 2023 - Léo Lajoie: "Eco-extraction of plants for the development of phytotherapy drugs", GREEN (UMR 408 SQPOV)

Date and place

Avignon University, Jean-Henri Fabre campus, agrosciences amphitheatre
7 July 2023 at 9.30 a.m.
defence in camera

Discipline

Chemistry

Laboratory

GREEN (UMR 408 SQPOV)

Management

• Prof. Farid Chemat
• Dr.-HDR. Anne-Sylvie Fabiano-Tixier

Composition of the jury

• Mr Giancarlo CRAVOTTO - Professor, University of Turin - Rapporteur
• Mr Werner KUNZ - Professor, University of Regensburg - Rapporteur
• Mrs Béatrice BAGHDIKIAN - PhD, Aix-Marseille University - Examiner
• Mr Philippe PICCERELLE - Professor, Aix-Marseille University - Examiner
• Mr Pierre BAUDUIN - Doctor-HDR, ICSM - Examiner
• Mrs Anne-Sylvie FABIANO-TIXIER - PhD, Avignon University - Thesis supervisor
• Mr Philippe ROBINET - Arkolabs Innovation Manager, Arkopharma - Guest

Summary of the thesis

The current context of global warming and health crises is constantly increasing consumer demand for natural health products. Food supplements based on medicinal plants can meet these needs. Obtaining such products generally requires one or more plant extraction stages to concentrate the bioactive molecules of pharmacological interest. Historically, and unfortunately still today, some extraction processes have used solvents that are toxic for the environment, industry and consumers alike. It is therefore important to replace these mainly petrochemical solvents with green biosourced solvents and, more generally, to apply the 6 principles of eco-extraction to guarantee the production of a plant extract that is as virtuous as possible for people and the environment.
Firstly, this manuscript explains why water is considered the green solvent par excellence and can therefore be used in eco-extraction. However, pure water used under normal conditions of pressure and temperature does not generally allow efficient extraction of the bioactive molecules of interest. This is why it is important to seek to improve this solvent by modifying physical and/or chemical parameters before incorporating it into a relevant eco-extraction process developed on an industrial scale. The most effective methods for improving the solvent power of water in plant extraction were presented, analysed and compared. In the light of these methods and particularly relevant recent research results, a new process for producing food supplements was studied.

The experimental part therefore focused on the development of an edible aqueous solvent, enabling efficient eco-extraction of the bioactive compounds of interest. In addition, thanks to its innovative composition, this solvent could be dried to obtain a dry extract. This was then subjected to direct compression tests in an attempt to obtain
natural tablets compatible with organic certification. The pharmaco-technical characteristics of these tablets were studied, as were the chemical composition and structure of the eco-extracts.
Although further optimisations and investigations are still required in order to envisage implementation on an industrial scale, promising results have been obtained at the various production stages studied. In particular, this thesis has shown that water modified with food products is capable of efficiently extracting a wide range of bioactive molecules, while at the same time making it possible to obtain powders that are potentially valuable in tablet form.

Key words : eco-extraction, medicinal plants, phytotherapy, techniques
intensification, industrial transposition.