Enzyme Catalyzed Synthesis of Water Soluble Mesalazine Oligomers and Evaluation of their Efficiency in Polypropylene Stabilization

5-Aminosalicylic acid, also known as mesalazine, was oxidized via biocatalytic pathway using Horseradish Peroxidase as catalyst. The spectroscopic measurement results indicated that amine and hydroxyl groups in monomer structure participated in polymerization reaction and carboxyl groups did not. The oxidation product consisted of a mixture of branched oligophenol and oligoaniline units and was well soluble in both organic and inorganic solvents including methanol, DMSO and H2O. The photoluminescence studies showed that both 5-aminosaliyclic acid and oxidation product exhibited green and blue light emission, respectively. Both compounds were subject to antioxidant assays. The oxidation product exhibited moderate antioxidant ability for all three assays. However, 5-aminosalicylic acid failed to chelate the ferrous ions. As antioxidant stabilizer for polypropylene, the efficiency of the oxidation product was also investigated.