Helleborus odorus subsp. cyclophyllus: An Unexploited Source of Antioxidant, Antimicrobial, and Cytotoxic Bioactivity

Helleborus sp. are small, perennial herbs with a wide distribution across central and southern Europe and Asia. Historically, extracts of these plants have been used in remedies exhibiting cathartic and anthelmintic effects; however, their adverse and toxic potential have also been reported. As such, Helleborus extracts have been trialled as alternative approaches to cancer treatment in rare cases. In this study, a detailed phytochemical characterisation of root extracts from Helleborus odorus subsp. cyclophyllus was performed in parallel with an in vitro assessment of their cytotoxicity and effect on cell phenotype. GC/EI/MS metabolite profiling revealed the complexity of the extract, which exhibited a high relative content of fatty acids (17.98%), with the most abundant group being the unsaturated fatty acids, followed by saturated and hydroxy fatty acids. Bioassays indicated the extract had antioxidant capabilities, while in vitro analysis demonstrated the extract induced a pro-oxidant phenotype that reduced cell viability, inhibited growth in bacterial (E. coli) and mammalian (human aortic endothelial cells) cell types, and exacerbated pro-inflammatory indices. Helleborus odorus subsp. cyclophyllus contains bioactive molecules that elicit a number of cellular responses, and the therapeutic potential of these molecules warrants further investigation.