Reactive oxygen species scavenging ability of a new compound derived from weathered coal.
The scavenging activity of three fulvic acids (named XWCS-1, XWCS-4, and XWCS-8 according to time taken for ozonolysis) obtained by ozonolysis of humic acid extracted from Xinjiang (China) weathered coal and a fulvic acid (named XWCFA) extracted from the same coal towards reactive oxygen species such as superoxide radical (O(2)(.)(-)) and hydroxyl radical ((.)OH) was investigated with an electron spin resonance (ESR)-spin trapping method using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trap. O(2)(.)(-) was generated with a hypoxanthine-xanthine oxidase system. (.)OH was generated by three different methods; (i) FeSO(4)-hydrogen peroxide (H(2)O(2)) system, (ii) Cu(en)(2)-H(2)O(2) system, and (iii) UVB photolysis of H(2)O(2). At physiological pH, XWCS-1 had the greatest O(2)(.)(-) scavenging activity, followed by XWCS-4, XWCS-8 and XWCFA. XWCFA had the greatest ?OH scavenging activity among the four fulvic acids, whereas XWCS-1 and XWCS-4 enhanced the production of (.)OH from a metal-catalyzed hydroxyl radical generating system, suggesting that these molecules act as prooxidants in the presence of metal ion.
National Institute of Radiological Sciences, 9-1 Anagawa 4-chome, Inage-ku, Chiba-shi 263-8555, Japan. ueda@nirs.go.jp
Jun-Ichi
J
Ueda
Nobuo
N
Ikota
Toshiyuki
T
Shinozuka
Tatsuaki
T
Yamaguchi
D001578:Benzopyrans / Q000737:chemistry*; D003031:Coal; D004578:Electron Spin Resonance Spectroscopy; D017382:Reactive Oxygen Species / Q000737:chemistry*
D001578:Benzopyrans; D003031:Coal; D017382:Reactive Oxygen Species; C005023:fulvic acid