Thesis by ACHARD-BACCATI Clémentine “Ethnopharmacological valuation of five Provençal plant species from the Luberon Regional Nature Park”.”

Madame ACHARD-BACCATI Clémentine, doctoral student at IMBE, team Functional ecology: from socio-ecological systems to molecules, will publicly defend his thesis on Friday 12 December 2025 at 9am in the Thesis Room, Faculty of Pharmacy, La Timone.

In front of a jury made up of :

• Anne Gauvin-Bialecki, Rapporteur, Professor, University of La Réunion
• François Chassagne, Rapporteur, Research Fellow, IRD Nouméa
• Dominique Laurain-Mattar, Chair of the jury, University Professor, University of Lorraine
• Gérald Culioli, Examiner, University Professor, Avignon University
• Béatrice BAGHDIKIAN, Director of thesis, Senior Lecturer HDR, Aix-Marseille University
• Elnur GARAYEV, PhD thesis co-director, Senior Lecturer, Aix-Marseille University
• Sylvie MOREL, Guest lecturer, University of Montpellier

Summary of work:

This thesis proposes an ethnopharmacological approach to the development of Provençal medicinal plants from the Parc Naturel Régional du Luberon. This approach is based on the ethnobotanical inventories carried out by Pierre Lieutaghi and Magali Amir in order to select five medicinal plant species used in traditional Provençal medicine for cutaneous purposes: Helichrysum stoechas, Pilosella officinarum, Plantago sempervirens, Rubus ulmifolius and Satureja montana.

Plant drugs from each selected species were extracted ultrasonically with a hydro-ethanol mixture, and the resulting extracts were fractionated by liquid/liquid extraction.

The extracts and fractions were subjected to biological screening to assess activities related to traditional uses: antioxidant (DPPH/ABTS in microplate and on-line UHPLC-DAD-DPPH/ABTS-MS/MS coupling), anti-inflammatory (NO inhibition), antimicrobial (inhibition diameters and MICs on skin microbiota strains) and healing (scratch-test on keratinocytes).

At the same time, the chemical composition was studied using UHPLC-HRMS/MS and GC-MS analyses. Dereplication and the use of molecular networks were used to describe the chemical diversity of the extracts and fractions, and to highlight the chemical families contributing to the biological activities assessed.

On-line UHPLC-DAD-DPPH/ABTS-MS/MS coupling was used to accurately determine the compounds responsible for the antioxidant activity. Given its high antioxidant potential and favourable natural abundance, the species Rubus ulmifolius has been selected for industrial development. Sanguiin-H6, identified as the main contributor to the antioxidant activity of R. ulmifolius, was isolated by preparative HPLC and its structure confirmed by NMR. The development of a specific HPLC-UV assay method and the implementation of a design of experiments made it possible to optimise the extraction conditions in order to increase the concentration of sanguiin-H6 in hydro-glycerol extracts.

Overall, the experimental results support local ethnopharmacological knowledge of skin uses, with the anti-oxidant, anti-inflammatory and anti-microbial profiles of the species studied.