Variability of secondary metabolites in the bark of Rhamnus cathartica L. from native and introduced population

The European buckthorn ( Rhamnus cathartica L.) – a shrub native to most parts of Europe and Western Asia – has been successfully naturalized in the Midwest and Northeast of the USA, dominating various habitats and displacing native species. It is known that Rhamnus cathartica L. plants contain a wide range of secondary metabolites with pharmacological effects. Permanent sample plots with R. cathartica – the species native for Belarus (two sites) and invasive in the USA (two sites) – were selected. This study investigated the level of anthraquinones, catechins, and leucoanthocyanins, and identified anthraquinones using HPLC with mass spectrometry and UV detection, showing a significant variation in these indicators depending on the conditions and the geographical area of growth. Rhamnus cathartica chemorases were identified, which will allow further isolation of samples with a required set of phenolic compounds and a directed selection for obtaining artificially introduced populations with an increased content of one or another valuable compound.