The focus of interest is on: 1. evaluating the nature of interactions between free radicals and antioxidants, melanin biopolymers, complex antioxidant systems, and drug-antioxidant systems, which are used in the prevention and treatment of, among others, lifestyle-related diseases (such as Alzheimer’s or Parkinson’s) or skin diseases, as well as the interactions of active substances with free radicals generated in cancer cells, 2. the search for new compounds of both natural and synthetic origin with potential anticancer activity for the development of modern drug formulations, including those with extended or controlled release of active substances, which enhance the therapeutic efficacy of medicinal products, 3. evaluation of the anticancer activity of selected triterpenoid compounds, both as monotherapy and in combination therapy with other cytostatic agents and small-molecule inhibitors of oncogenic signaling pathways.