Valorization of Himalayan balsam (Impatiens glandulifera Royle) waste to design bioactive extracts with a potential protective activity on the human vascular system

Invasive alien plant species are plants that are non-native to a particular ecosystem. Many of them are now spreading at an alarming rate, threatening local biodiversity, endangering certain animal species, and causing great damage to urban infrastructure. According to the United Nations Intergovernmental Platform for Biodiversity and Ecosystem Services, up to one fifth of the Earth’s surface is at risk, requiring immediate intervention. Eradication and containment strategies are ineffective and environmentally or economically unsustainable, so practical uses for these invaders are being actively explored. One such problematic species is surely Himalayan balsam (Impatiens glandulifera Royle), causing serious concern in most EU countries, Canada, North America, New Zealand, and Russia. Thus, the main objective of this project is to demonstrate that Himalayan balsam waste, which is a by-product of its mechanical containment, is a sustainable source of antioxidants that could be transformed into products with beneficial effects on human vascular function. Cardiovascular diseases remain the leading cause of death in the world, and there are many ongoing efforts to combat this pandemic. The vascular endothelium constitutes the inner cellular lining of all blood vessels and as such represents the largest human organ and an important biomedical target. In the proposed research, we aim to successfully extract antioxidants such as carotenoids and different phenolic compounds from the underground and aerial parts of Himalayan balsam. By combining 5 plant parts with various sustainable extraction solvents (e.g., water and alcoholic mixtures thereof, as well as hydrophobic natural deep eutectic solvents) and extraction techniques (e.g., maceration, pressurized solvent extraction, and ultrasound-assisted extraction), a variety of potentially bioactive extracts will be obtained. The entire extraction workflow will be guided by the 12 principles of green chemistry as the strain of research and technological innovation on the environment has been escalating in recent years. The Himalayan balsam extracts obtained will be thoroughly studied to determine the major classes of antioxidants that contribute to the total antioxidant activity measured by established radical scavenging assays. Further, to demonstrate their safety (the absence of any toxic matrix components) and their beneficial effects on the human vascular system, the extracts will be subjected to a series of in vitro assays using human endothelial cell lines EA.hy926. Activities will include: (i) measurement of cell viability, (ii) measurement of cellular antioxidant activity, (iii) identification of concentration changes of relevant intracellular biomarkers (e.g., bilirubin, biliverdin, glutathione, and uric acid), and (iv) measurement of mitochondrial toxicity. Finally, based on the comprehensive data obtained, the extracts eliciting the most relevant cellular response will be subjected to bioassay-guided fractionation to identify the key chemical constituents of the plant responsible for the observed effects. In combination with targeted enzymatic assays, deeper insight into the role of these species within the endothelium and their effect on signalling pathways will also be obtained. All efforts within the proposed project are expected to eventually converge towards an extract or extracts of Himalayan balsam with health-promoting properties that can be transformed into a new range of sustainable food supplements through further scientific intervention at a higher TRL level. Moreover, the exhaustive evaluation platform developed within the project, which integrates the fields of analytical chemistry, cell biology, and biochemistry, has great potential to form the future basis for a broader and more credible evaluation of new sources of bioactive compounds.