Dermatological plants and their uses in the Receptarium of Burkhard III from Hallwyl from 16th century Switzerland: Data mining a historical text and preliminary in vitro screening

Ethnopharmacological relevanceHistorical texts on materia medica can be an attractive source of ethnopharmacological information. In recent decades, various research groups have investigated corresponding resources from Europe and the Mediterranean region, pursuing different objectives. Regardless of the method used in such a work, the indexing of textual information and its conversion into data sets useful for further investigations represents a significant challenge. Aim of the studyFirst of all, this study aims to systematically catalogue pharmaco-botanical information in the Receptarium of Burkhard from Hallwyl (RBH) in order to identify candidate plants in a targeted manner. Secondly, the potential of RBH as a resource for pharmacological investigations will be assessed by means of a preliminary in vitro screening. Materials and methodsWe developed a relational database for the systematic recording of the parameters composing the medical recipes contained in the historical text. Focusing on dermatological recipes, we explored the mentioned plants and their uses by drawing on specific literature. The botanical identities (candidate species) suggested in the literature for the historical plant names were rated based on their plausibility of being the correct attribution. The historical uses were interpreted by consulting medical-historical and modern clinical literature. For the subsequent in vitro screening, we selected candidate species used in recipes directed at the treatment of inflammatory or infectious skin disorders and wounds. Plants were collected in Switzerland and their hydroethanolic crude extracts tested for possible cytotoxic effects and for their potential to modulate the release of IL-6 and TNF in LPS-stimulated whole blood and PBMCs. ResultsThe historical text analysis points up the challenges associated with the assessment of historical plant names. Often two or more plant species are available as candidates for each of the 161 historical plant names counted in the 200 dermatological recipes in RBH. At the same time, the 56 medicinal uses mentioned in these recipes illustrate, that the details provided in the text about the skin problem in question enable conclusions to be drawn based on which the presumed underlying medical condition and its pharmacological basis can be narrowed down. On this basis, 11 candidate species were selected for in vitro screening, four of which were used in RBH in herbal simple recipes and seven in a herbal compound formulation. None of the extracts tested showed a noteworthy effect on cell viability except for the sample of Sanicula europaea. Extracts were tested at 50 {micro}g/mL in the whole blood assay, where especially Vincetoxicum hirundinaria or Solanum nigrum showed inhibitory or stimulatory activities. In the PBMC assay, the root of Vincetoxicum hirundinaria revealed a distinct inhibitory effect on IL-6 release (IC50 of 3.6 {micro}g/mL). ConclusionsUsing the example of RBH, this study illustrates a possible ethnopharmacological path from unlocking the historical text and its subsequent analysis, through the selection and collection of plant candidates to their in vitro investigation. Fully documenting our approach to the analysis of historical texts, we hope to contribute to the discussion on solutions for the digital indexing of premodern information on the use of plants or other natural products.