ETHNOBOTANICAL SURVEY IN VALMALENCO (SONDRIO, ITALY): STUDY AND ENHANCEMENT OF THE PLANT AND CULTURAL BIODIVERSITY

Background - This thesis is part of the three-year European Italy-Switzerland Interreg research program B-ICE (ID. 63143) aimed at promoting a sustainable management model for the ongoing climate change in Valmalenco (Sondrio, Lombardy, Italy) and to reach new sources for the local enhancement through the proposal of an ethnobotanical investigation. In an era in which the awareness about the impact of global warming on mountain biodiversity is growing, the preservation of the traditional know-how related to the plant uses can represent an alternative strategy for the sustainable development of Alpine regions, in accordance with the “cultural tourism” plans. Moreover, the abandonment of local traditional practices might involve a loss of access to a stock of bioactive compounds potentially useful for therapeutic applications. According to an ethno-direct approach, candidate plants can be selected by using information collected in ethnobotanical field research and the uses reported by informants need to be verified through laboratory insights. From 2019 to 2022, the ethnobotanical survey was conducted in the municipalities of Chiesa in Valmalenco, Caspoggio, Lanzada, Spriana, and Torre di Santa Maria, where traditional know-how related to the use of plants still survive. Aim – In this context, the doctoral project pursued the conduction of the ethnobotanical survey, followed by the in-depth analysis of the primary data for further scientific studies in the pharmaceutical filed. To this purpose, the work combined sequential multidisciplinary and complementary research activities with the aim of selecting a medicinal plant species and understanding its values in terms of potential source of new bioactive compounds. Materials and Methods – The ethnobotanical field work allowed the documentation of the traditional uses of the autochthonous plant species trough the proposal of open and semi-structured interviews to the local communities, paying attention to the therapeutic uses of plants. Primary data were archived in a database and analysed by means of pivot tables and ethnobotanical indexes (Informant Consensus Factor, Fidelity Level), reaching the selection of a medicinal plant, worthy of further laboratory insights. The experimental investigation started with a micromorphological survey on the traditional herbal drug by means of Light (LM), Fluorescent (FM) and Scanning Electron Microscopy (SEM). The purpose was to identify the secreting structures responsible for the productivity of the secondary metabolites, together with the main chemical classes of the secreted compounds. Next step pursued the phytochemical characterization of the traditional preparation to better understand its potential in terms of bioactive compounds. To this end, methanol and aqueous extracts were obtained from the traditional drug and the chromatographic separation was performed by High Performance Liquid Chromatography coupled with a Mass Spectrometer (HPLC-MS/MS), equipped with an ESI source, and acquiring spectra both in negative and positive ion mode. Once characterized, the preliminary biological activity of the traditional preparation was assessed, coherently with the popular use. Different concentrations of both the extracts were then evaluated for their antioxidant (NRF2 pathway activation) and anti-inflammatory (NFKB pathway inhibition) potential by in vitro cell-based models, using two different cell lines (HEK293, R3/1). The experimental phase on the target species ended with the investigation on the preparation’s bitter taste, described by local people as responsible for the traditional therapeutic effect. Thus, preliminary evaluations concerning the interaction of the identified bioactive compounds with bitter taste receptors (TAS2R46) were evaluated through molecular docking analysis (PLANT and GOLD software). Results – This research resulted the first ethnobotanical investigation in Valmalenco. A total of 401 informants were interviewed, outlining the use of 227 plant species, belonging to 77 families. The traditional uses were classified in 12 fields of use and the therapeutic sector resulted the second one in terms of citations (n=5147). The medicinal field revealed a total of 110 species belonging to 49 families, and Arnica montana L., Malva sylvestris L., Pinus mugo Turra, and Achillea moschata Wulfen resulted the most used plants by the folk medicine. According to the primary data, and supported by the ICF and FL values, digestive tract disorders reached one of the highest agreements among the informants, and the decoction of A. moschata air-dried flower heads resulted the most widespread remedy to treat digestive problems, gastritis, ulcer, and gastric reflux. Considering this, and since literature data resulted to be scarce, A. moschata was selected as the target species and, for the first time, the indumentum of its leaves, flowering stems, and flower heads was investigated, detecting both covering and glandular airs. The 10-celled biseriate glandular trichomes resulted the only glandular morphotype, as well as the main sites of synthesis, accumulation, and release of terpenes, polyphenols, and flavonoids. Targeted data analysis of the qualitative profile of the methanol and aqueous extracts allowed the identification of 31 compounds. Out of the total, 5 were phenolic acids, 13 flavonols, and 13 flavons, with caffeoyl and dicaffeoylquinic acid derivatives, as well as glycosides and aglycones of luteolin, apigenin, kaempferol, and isorhamnetin among the main components. The aqueous phytocomplex show a significant increased of NRF2 pathway activation already at 10 μg/mL and resulted to be able to significantly decrease the inflammatory response already at 1 μg/mL. In addition, docking results reasonably suggested that dicaffeoylquinic acid isomers, as well as luteolin and isorhamnetin glycosylated forms, resulted to be among the main responsible for the decoction strong bitter taste. Return to the population – Finally, in an Open Science context, the project provided for the return of the research data to the local communities with a short and long-term perspectives. In July 2022, a two-day event was dedicated to make people participate in the research progress. Moreover, the planning and realization of two Botanic Gardens was pursued, as “open-air museums” of the malenca bio-cultural diversity. The “Didactic Botanic Garden” has been designed in Caspoggio for children and school to disclose the local tradition of plants in a practical and interactive way. The “High-rise Botanic Garden” in Sant’Antonio di Caspoggio has been conceptualized as a direct product of the ethnobotanical research, with special care also to the world of disability, offering a more scientific in-depth approach to the plant entities. Works have started and the garden will be inaugurated in July 2023. Conclusion – To conclude, the value of this doctoral project deal with its multidisciplinary approach, that focuses on the modern conception of the ethnobotanical investigation as a potential way of research to find out promising natural bioactive compounds. Moreover, this path allowed to document, preserve, and enhance the bio-cultural heritage of Valmalenco, resulting in the involvement of the local communities in the process of safeguarding the value of the malenca cultural and natural identity as a new source of territorial development.