Abstract:
:The superoxide O2(·-) scavenging reaction of (+)-catechin (Cat), quercetin (Que), rutin, and α-tocopherol (α-TOH) as natural phenolic compounds is investigated on the basis of electrochemical and ESR spectral measurements with the aid of density functional theory (DFT) calculations. Reversibility of the O2/O2(·-) redox couple is significantly affected by the presence of the phenolic compounds. The catechol moiety of Cat, Que, and rutin plays an essential role in concerted proton-coupled electron transfer (PCET) to HO2(·) derived from O2(·-) to give H2O2 and the corresponding o-benzoquinone radical anions. On the other hand, the presence of α-TOH causes sequential electron and proton transfers to HO2(·) to give H2O2 and the α-tocopheroxyl radical. These electron transfers in the presence of the phenolic compounds are inferred from the ESR spectral measurements. The DFT calculation results suggest that the O2(·-) scavenging reaction of the natural phenolic compounds proceeds efficiently with the one-step concerted PCET or sequential PCET mechanism.
journal_name
Chem Pharm Bull (Tokyo)journal_title
Chemical & pharmaceutical bulletinauthors
Nakayama T,Uno Bdoi
10.1248/cpb.c15-00447subject
Has Abstractpub_date
2015-01-01 00:00:00pages
967-73issue
12eissn
0009-2363issn
1347-5223journal_volume
63pub_type
杂志文章abstract::We developed a rapid and efficient analytical technique for cyclosporine A using HPLC on a column packed with 2-µm nonporous octadecylsilyl silica particles. Under optimized conditions, cyclosporine A was separated with high resolution from other cyclic peptides within 3 min, because the mass transfer resistance in th...
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