Production of hydroxyl radical by redox active flavonoids

Journal Article · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:7025542

Kalyanaraman, B; Hodnick, W F; Pardini, R S

The authors have previously shown that flavonoids autoxidize and generate superoxide (O/sub 2//sup -/) and hydrogen peroxide (H/sub 2/O/sub 2/), suggesting that hydroxyl radical (OH) could be formed via the metal-ion catalyzed Haber-Weiss reaction. In the presence of ethylenediamine tetraacetic acid (EDTA) and 5,5-dimethyl-1-pyrroline-1-oxide (DMPO), myricetin, quercetagetin and quercetin gave an ESR signal for the DMPO-OH spin adduct, and the DMPO-Eto adduct in the presence of excess ethanol, indicating the production of free OH. The addition of FeCl/sub 3/ to the reaction mixture resulted in a dramatic increase in the DMPO-OH signal. Without chelator (EDTA) there was no signal and the presence of diethylenetriamine-pentaacetic acid (DETAPAC) greatly diminished the signal. The presence of superoxide dismutase (SOD) had no effect on the signal while catalase completely abrogated the signal. The addition of Fe (III)-EDTA to flavonoid solutions under anaerobic conditions produced time dependent auxochromic shifts in their absorption spectra and resulted in the reduction of Fe (III) to Fe (II). These data suggest that the flavonoids autoxidize to produce O/sub 2//sup -/ and H/sub 2/O/sub 2/ by dismutation and in the presence of Fe (III)-EDTA the flavonoid can directly reduce the Fe (III) to Fe (II) resulting in the production of OH through Fenton chemistry.

• Research Organization: Medical College of Wisconsin, Milwaukee
• OSTI ID: 7025542
• Report Number(s): CONF-8606151-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
FLAVENOIDS
REDOX REACTIONS
SUPEROXIDE RADICALS
BIOSYNTHESIS
BIOCHEMICAL REACTION KINETICS
EDTA
ELECTRON SPIN RESONANCE
IRON
REDOX POTENTIAL
SUPEROXIDE DISMUTASE
AMINO ACIDS
CARBOXYLIC ACIDS
CHELATING AGENTS
CHEMICAL REACTIONS
ELEMENTS
ENZYMES
KINETICS
MAGNETIC RESONANCE
METALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDOREDUCTASES
RADICALS
REACTION KINETICS
RESONANCE
SYNTHESIS
TRANSITION ELEMENTS
550200* - Biochemistry