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Reaction of dipyridamole with the hydroxyl radical
Author(s) -
Iuliano Luigi,
Pratico Domenico,
Ghiselli Andrea,
Bonavita Maria S.,
Violi Francesco
Publication year - 1992
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02536149
Subject(s) - deoxyribose , chemistry , radiolysis , radical , hydroxyl radical , reaction rate constant , dipyridamole , kinetics , photochemistry , medicinal chemistry , organic chemistry , biochemistry , medicine , physics , quantum mechanics , radiology , dna
Dipyridamole [2,6‐ bis ‐diethanolamino‐4,8‐dipiperidinopyrimido‐(5,4‐d) pyrimidine], a well known platelet aggregation inhibitor, shows powerful hydroxyl radical scavenging activity by inhibiting OH‐dependent salicylate and deoxyribose degradation. Steady‐state competition kinetics experiments with deoxyribose were carried out to evaluate the second‐order rateconstant for the reaction between hydroxyl radical and dipyridamole. OH· radicals were generated either by a Fenton‐type reaction or by X‐ray irradiation of water solutions. A second‐order rate constant k (Dipyridamole+OH·) of 1.72±0.11×10 10 M −1 s −1 and of 1.54±0.15×10 10 M −1 s −1 was measured by Fenton chemistry and by radiation chemistry, respectively. Mannitol was used as an internal standard for hydroxyl radicals in steady‐state competition experiments with deoxyribose. A rate constant k (Mannitol+OH·) of 1.58±0.13×10 9 M −1 s −1 and 1.88±0.14×10 9 M −1 s −1 was measured in the Fenton model and in the water radiolysis system, respectively. Both these rate constants are in good agreement with the published data obtained by the “deoxyribose assay” and by pulse radiolysis.