Res. Chem. Intermed.
, Vol. 31, No. 7–8, pp. 667–678 (2005)
Also available online - www.vsppub.com
The radioprotection and antioxidant properties
B. S. PATRO
, S. ADHIKARI
, G. J. CHINTALWAR
, S. CHATTOPADHYAY
and T. MUKHERJEE
Bio-Organic Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
Radiation Chemistry & Chemical Dynamics Division, Bhabha Atomic Research Centre, Mumbai
400 085, India
Received 21 April 2004; accepted 28 June 2004
Abstract—The reactions of hydroxyl and glutathiyl radicals with dehydrogingerdione (1)have
been studied using biochemical assays and the pulse radiolysis technique in order to understand its
radioprotective and antioxidant action. It was found to inhibit the Fenton-mediated 2-deoxyribose
oxidation, as well as γ -ray-induced plasmid DNA strand breaks in a concentration-dependent fashion.
The pulse radiolysis studies revealed its high reactivity with the hydroxyl and glutathiyl radicals. With
the hydroxyl radicals, it initially formed three species, an adduct, a phenoxyl and a methylenic radical.
The bimolecular rate constants for the formation of these species were the same (approx. 6.8 × 10
/mol per s). The initially formed adduct also produced the phenoxyl radical at a later stage. In the
case of glutathiyl-radical-induced oxidation, an adduct at the α–β double bond was formed as the sole
species. Its identity as a carbon-centered radical was inferred from the result of the oxygen effect on
the decay of the adduct radical. At a later stage, the adduct radical also produced the phenoxyl radical
through an intramolecular radical transformation. A suitable mechanism for the oxidation reactions
of 1 has been proposed.
Keywords: Dehydrogingeridone; pulse radiolysis; radioprotection; plasmid pBR322.
Medical and nutritional experts have seriously noted the antioxidant properties of
food constituents in recent years, since oxidation of biological molecules has been
postulated to induce a variety of pathological events such as atherogenesis ,
carcinogenesis  and ageing . These damaging events are caused by stress
induced by various free radicals. Several dietary compounds are known to prevent
them, primarily through their radical scavenging potentials. Amongst dietary
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