The Hydroxyl Radical - Free-Radical-Induced DNA Damage and Its Repair - page 65

Table 3. 8 . Plasma levels of 2,3-dihydroxybenzoate and 2,5-dihydroxybenzoate 2 h after
administering salicylic acid (rat; Ste-Marie et al. 1996) or aspirin. (man; Isobe et al. 1996)

mg kg − 1 [2,3-DHB]/10 − 9 mol dm − 3 [2,5-DHB]/10 − 9 mol dm − 3

Species

Rat 300 95 264

Man

10 − 20 63 ± 24 832 ± 309

in the former case at a 15 times higher concentration. However, close to equal

2,3-dihydroxybenzoate levels were found in the rat and the human despite the
fact that in the rat the scavenging capacity of salicylate was about 15 times higher
(Eq. 43). Assuming an equal rate of • OH production in these two species, the rat
should thus have shown 15 times higher 2,3-dihydoxybenzoate levels. This dis-
crepancy is even larger considering that smaller animals have typically higher
metabolic rates and hence a potentially higher rate of free-radical production.
With this cautionary remark in mind, we would like to mention some studies
where attempts have been made to monitor • OH production and a variety of con-
ditions, including stressed systems: dextran sulfate-induced colitis (Blackburn
et al. 1998), diabetes patients (Ghiselli et al. 1992), obstructive jaundice of rats
(Tsay et al. 1998), ischemic reperfused mycocardium (Das et al. 1989), activated
human neutrophils (Kaur et al. 1988), healthy humans (Grootveld and Halliwell
1988), fecal f flora (Owen et al. 1996), in chondrocytes and cartilage (Tiku et al.
1998).

∼

References

Acworth IN, Bogdanov MB, McCabe DR, Beal MF (1999) Estimation of hydroxyl free radical levels
in vivo based on liquid chromatography with electrochemical detection. Methods Enzymol
300:297−313
Akhlaq MS, von Sonntag C (1987) Intermolecular H-abstraction of thiyl radicals from thiols and the
intramolecular complexing of the thiyl radical with the thiol group in 1,4-dithiothreitol. A pulse
radiolysis study. Z Naturforsch 42c:134−140
Ames BN, Shigenaga MK (1992) Curr Comm Cell Molec Biol 5:1−22
Anbar M, Meyerstein D, Neta P (1966a) The reactivity of aromatic compounds toward hydroxyl radi-
cals. J Phys Chem 70:2660−2662
Anbar M, Meyerstein D, Neta P (1966b) Reactivity of aliphatic compounds towards hydroxyl radicals.
J Chem Soc Perkin Trans 2 742−747
Armstrong WA, Facey RA, Grant DW, Humphreys WG (1963) A tissue-equivalent chemical dosimeter
sensitive to 1 rad. Can J Chem 41:1575−1577
Aruoma OI (1994) Deoxyribose assay for detecting hydroxyl radicals. Methods Enzymol 233:57−66
Ashton L, Buxton GV, Stuart CR (1995) Temperature dependence of the rate of reaction of OH with
some aromatic compounds in aqueous solution. J Chem Soc Faraday Trans 91:1631−1633
Asmus K-D, Möckel H, Henglein A (1973) Pulse radiolytic study of the site of OH • radical attack on
aliphatic alcohols in aqueous solution. J Phys Chem 77:1218−1221