Antioxidant Activity and Mechanism of Action of Some Synthesised Phenolic Acid Amides of Aromatic Amines

摘要

The antioxidative activities and mechanism of action were studied of eight synthesised cinnamoyl- and hydroxycin-namoyl amides of biogenic amines (caffeoyldopamine, einnamoyldopamine, p-coumaroyldopamine, feruloyldop amine, sinapoyldopamine, caffeoylphenylethylamine, caffeoyltyramine, and caffeoyltryptamine) in a wide concentration range (2.5-20 x 10~(-1)M) during autoxidation of triacylglycerols of sunflower oil. It was established that all amides exhibited excellent antioxidant activity, higher than or comparable with that of eaffeic acid. The best activity was shown by caffeoyldopamine followed by cinnamoyldopamine and caffeoyltyramine. The analysis of the kinetic data obtained showed that the presence of hydroxyl groups in the amino part (derivatives of dopamine and tyramine) led to direct oxidation of the molecules during the process and stabilisation of the resulting radicals. In contrast, the amides without hydroxyl groups in the amino part participated in the side reaction with peroxides and the resulting radicals took part in one side reaction of the chain propagation as did caffeic acid.