Abstract/Summary

Traditional Medicine systems around the world are legacies of all humans. We are still far away from understanding all the myths of how the systems arose and were disseminated, and we hardly know to what extent they support health. Using phylogenetic methods could help us to unravel the stories of plants used in medicine in a more comprehensive way, to include traditional knowledge about them and how that knowledge was transmitted or evolved. Phylogenies, by accounting for the taxonomy or relatedness of the plants, help us better understand the characteristics of the plants and how the ecological environment might affect the uses by local people. Community phylogenetic methods, borrowed from ecology, are increasingly applied in studies of plants used in medicine, to understand the pattern of selection. Phylogenies are also used to resolve the taxonomically difficult medicinal plant groups. This thesis standardized the community phylogenetic method for studies of plants used in medicine, by matching the questions and models and metrics in the method and suggesting how the phylogenetic framework should be selected. This method was used to investigate the humoral concept of four traditional medicine systems: Ayurvedic medicine of India, Unani medicine of India, Traditional Chinese Medicine (TCM), and Traditional Persian medicine. Plants are assigned cold, hot and neutral properties in these systems, and it has been widely accepted the concepts were transmittable. In this thesis we showed that the plants with these properties are not selected from the same evolutionary lineages, and that attributes assigned to the plants are strikingly different among cultures. The medicinal use of a plant could be shaped by the cultural and floristic environment, it also could be influenced by the evolutionary relations of a plant itself. To have a better understanding of TCM, I applied a more established method to study the concept of Daodi, which is sometimes compared to the concept of terroir, whereby the location where the plant is grown brings extra value. This thesis shows the location is associated with the plant part used in medicine, and availability is crucial when selecting plants for medicine. Finally, a phylogenomic approach was applied to genus Cistanche (Orobanchaceae), which includes species that are used as the important TCM drug Cistanche Herba. We use targeted enrichment to capture the single copy gene regions of the nuclear genome, which were used as characters to estimate a phylogeny to resolve taxonomic problems for Cistanche plants distributed in China.