Potent 2,2-Diphenyl-1-picrylhydrazyl Radical-Scavenging Activity of Novel Antioxidants, Double-Stranded Tyrosine Residues Conjugating Pyrocatechol

作者：Kobayashi Shigeki^*; Wakl Tsukasa; Nakanish Ikuo; Matsumoto Ken ichiro; Anzai Kazunori

来源：CHEMICAL & PHARMACEUTICAL BULLETIN, 2010, 58(11): 1442-1446.

DOI：10.1248/cpb.58.1442

• antioxidant
• 2,2-diphenyl-1-picrylhydrazyl radical
• electron spin resonance
• tyrosine residue
• chemical hardness

New potent antioxidants conjugating the catechol (=pyrocatechol; pyrCat) group to two N-termini of modified double-stranded tyrosine residues were synthesized and showed radical scavenging activity with 2,2-diphenyl-1-picrylhydrazyl radical (DPPH radical, DPPH(center dot)) as a free radical model, second-order rate constants for the DPPH(center dot) scavenging reaction, and the results from electron spin resonance (ESR) studies. It was found that the tyrosine (Tyr) residue and pyrCat containing new antioxidants developed in the study have about 3-20 times more potent antioxidative activity than Trolox, pyrCat, and L-ascorbic acid (VC). In order to elucidate the relationship between antioxidant activity and the molecular orbital states, and to design potent antioxidants we present an interesting approach using an absolute hardness (eta)-absolute electronegativity (chi) diagram based on chemical hardness. It was shown that quantum chemicals were required to develop potent antioxidants.

• 出版日期2010-11