Synthesis and antioxidant capacities of hydroxyl derivatives of cinnamoylphenethylamine in protecting DNA and scavenging radicals

Abstract

Cinnamoylphenethylamine (CNPA) derivatives including feruloylphenethylamine (FRPA), caffeoylphenethylamine (CFPA), cinnamoyltyramine (CNTA), feruloyltyramine (FRTA) and caffeoyltyramine (CFTA) were synthesized in order to investigate the influence of the number and position of hydroxyl group on Cu²⁺/glutathione (GSH) and 2,2′-azobis(2-amidinopropane hydrochloride) (AAPH)-induced oxidation of DNA. The radical-scavenging properties of these CNPA derivatives were also evaluated by trapping 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonate) cationic radical (ABTS^+•), 2,2′-diphenyl-1-picrylhydrazyl radical (DPPH) and galvinoxyl radical. In addition, these CNPA derivatives were tested by linoleic acid (LH)-β-carotene-bleaching experiment. The chemical kinetic was employed to treat the results from AAPH-induced oxidation of DNA and gave the order of antioxidant ability as CFTA > CFPA > FRTA > FRPA. CFTA and CFPA also possessed high abilities to inhibit Cu²⁺/GSH-mediated degradation of DNA, whereas FRPA and FRTA can protect LH against the auto-oxidation efficiently. Finally, CFPA and FRPA exhibited high activity in trapping ABTS^+•, DPPH and galvinoxyl radicals. Therefore, the cinnamoyl group bearing ortho-dihydroxyl or hydroxyl with ortho-methoxyl benefited for CNPA derivatives to protect DNA, while hydroxyl in tyramine cannot enhance the radical-scavenging abilities of CNPA derivatives.

Keywords::

• Cinnamoylphenethylamine
• Ceratostigma willmottianum
• free radical
• oxidation
• antioxidant
• DNA

This paper was first published online on Early Online on 9 December 2010.