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Updated: Aug 11, 2026

Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development
Published on: April 15, 2013
Radical-induced oxidation of metformin
H Khouri1, F Collin, D Bonnefont-Rousselot
1Laboratoire de Chimie Physique UMR 8601-CNRS, Université Paris 5, France. hania.khouri@univ-paris5.fr
Abstract:
Metformin (1,1-dimethylbiguanide) is an antihyperglycaemic drug used to normalize glucose concentrations in type 2 diabetes. Furthermore, antioxidant benefits have been reported in diabetic patients treated with metformin. This work was aimed at studying the scavenging capacity of this drug against reactive oxygen species (ROS) like *OH and (O2*-)-free radicals. ROS were produced by gamma radiolysis of water. The irradiated solutions of metformin were analyzed by UV/visible absorption spectrophotometry. It has been shown that hydroxyl free radicals react with metformin in a concentration-dependent way. The maximum scavenging activity was obtained for concentrations of metformin > or = 200 micromol.L(-1), under our experimental conditions. An estimated value of 10(7) L.mol(-1).s(-1) has been determined for the second order rate constant k(*OH + metformin). Superoxide free radicals and hydrogen peroxide do not initiate any oxidation on metformin in our in vitro experiments.
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