Hydroxyl radical scavenging activity of compatible solutes

Compatible solutes were assessed for their hydroxyl radical scavenging activity by their ability to compete in two different hydroxyl radical generating and detecting systems. Hydroxyl radicals were generated by ascorbate-hydrogen peroxide or by xanthine oxidase-hypoxanthine-hydrogen peroxide. They were detected by hydroxylation of salicylate or by denaturation of malate dehydrogenase. Of the compatible solutes tested, sorbitol, mannitol, myo-inositol and proline were effective hydroxyl radical scavengers. Glycinebetaine was ineffective. The role of compatible solutes as hydroxyl radical scavengers in vivo is discussed.