The natural and synthetic C5-curcuminoid derivatives own various pharmacological effects, among which the proved antiproliferative, antidiabetic and antioxidant effects can be emphasized. In the framework of the present program, the aim of our study is to investigate the mechanism of action and the structure-activity relationship of the newly synthetized compounds. We plan to analyze how the steric, electronic and hydrophobic properties of the compounds affect their cytotoxic activities and the covalent and non-covalent interactions which might play an important role in the effect. For determination of the relevant physico-chemical properties, and antioxidative pool chromatographic and spectroscopic methods are applied. The antiproliferative effects are tested on different cell cultures. Further aim is to study the transportmechanisms of the derivatives using different membrane modells and to investigate the metabolic transformations in a rat modell under physiological and pathological (e.g. diabetes) conditions.