OH scavenging activity

MSA is derivatized with a diazonium salt to produce a diazosulfone, which is quantified by HPLC [157]. The flavonoids catechin, epicatechin, 7,8-dihydroxyflavone, and rutin showed a OH scavenging activity 100 to 300 times higher than mannitol, whereas baicalein (5,6,7-trihydroxyflavone), quercetin, myricetin, and morin enhanced the OH production [16]. The pro-oxidant activity of morin increased with an increasing concentration of morin, whereas an increasing concentration of the other three flavonoids did not enhance their pro-oxidant activity. Hanasaki et al. suggested that these pro-oxidant flavonoids produce H2O2 during their auto-oxidation, which then stimulates the Fenton reaction [16]. 

If an aromatic compound reacts with an OH radical to form a specific set of hydroxylated products that can be accurately identified and quantified in biological samples, and one or more of these products are not identical to naturally occurring hydroxylated species, i.e. not produced by normal metabolic processes, then the identification of these unnatural products can be used to monitor OH radical activity therein. This is likely to be the case if the aromatic detector molecule is present at the sites of OH radical generation at concentrations sufficient to compete with any other molecules that might scavenge OH radical. 

Mirkov SM, Djordjevic AN, Andric NL, Andric SA, Kostic TS, Bogdanovic GM, Vojinovic-Miloradov MB, Kovacevic RZ (2004) Nitric oxide-scavenging activity of polyhydroxylated fullerenol, C60(OH)24. Nitric Oxide 11 201-207. 

The monoterpene ketones menthone and isomenthone [159, 166] exhibited OH- radical scavenging activity. Depending on the method employed, different activities for anethole have been reported [153, 169]. 

It may be mentioned that to study the effects of sensitizers on DNA radicals by y-irradiating biologically active DNA in aqueous solution in the presence of sensitizers does not provide useful information, since under such conditions the sensitizers scavenge -OH and thus protect rather than sensitize (Lafleur and Lo-man 1982 for -OH-scavenging see Whillans et al. 1975). 

B. nigra (cant.) Antioxidant (cont.) -Scavenging activity in vitro and in vivo against 02, H202, OHC1, OH [17]... 

Caryopteris incana Incanoside Antioxidant Scavenging activity against DPPH, OH and 02 Active [96]... 

The 3- and 5-OH groups are, together with the 4-oxo function, essential for maximal radical scavenging activity. In the absence of a C2-C3 double bond, the presence of an aliphatic 3-OH group does not contribute to the radical scavenging activity [117]. 

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