The research in the frame of the project focuses on the design, preparation and characterization of a panel of ruthenium-based organometallic complexes suitable for applications in efficient synthesis of antioxidants by metathetic catalytic routes. Our studies are dealing primarily with high-performing ruthenium catalysts incorporating arene and ancillary N-heterocyclic carbene (NHC) ligands. The activity, chemoselectivity and functional group tolerance of these catalytic systems in synthesis of antioxidants pertaining to polyhydroxylated aromatics is examined aiming at attaining improved yields and obtaining products with high purity levels. Advanced spectroscopic investigations by FTIR, UV-VIS, NMR and Mass Spectrometry are being jointly used for the structural characterization of catalysts and products