Metabolomical study of Cladonia Lichens

Lichens are complex symbiotic ecosystems characterized by remarkable chemical diversity, including secondary metabolites uniquely produced by them. Due to their high sensitivity to environmental changes, they are widely recognized as bioindicators of ecosystem health. Within this group, the genus Cladonia is notable for its broad ecological distribution, morphological plasticity, and rich chemodiversity, which have supported taxonomic, ecological, and ethnobotanical studies. However, despite extensive phytochemical investigations using classical chromatographic methods, comprehensive metabolomic analyses of Cladonia remain limited. This thesis provides an integrated overview of the phytochemistry and bioactivities of the genus Cladonia and applies an untargeted, NMR-based metabolomic approach to four species (Cladonia foliacea, Cladonia polycarpoides, Cladonia rangiformis, and Cladonia rei). A critical literature review was conducted to summarize current knowledge on secondary metabolites and biological activities, highlighting both chemical diversity and the limitations of traditional identification methods. Hydroalcoholic extracts of the selected species were then analyzed using ¹H-NMR spectroscopy, complemented by UHPLC-MS when necessary. Multivariate statistical analysis was employed to explore metabolic variation and identify discriminant metabolites among species. The metabolomic analysis revealed distinct and reproducible metabolic fingerprints for each species, reflecting differences in the relative abundance of characteristic biomarkers. These results demonstrate that NMR-based metabolomics, combined with chemometric tools, is a robust and unbiased approach for comparing complex lichen metabolomes. This strategy provides valuable insights into chemotaxonomy and intraspecific variability, with potential applications in environmental monitoring, biodiversity assessment, and sustainable ecosystem management. Overall, this work advances the understanding of Cladonia chemical diversity and supports metabolomics as a powerful complementary tool in lichenology, natural products research, and studies of ecosystem health.