Synthesis, radical scavenging activity and structure–activity relationship of uric acid analogs

Abstract

Uric acid (UA) is known to play an important role as an endogenous antioxidant. However, its insolubility in the serum is a risk for hyperuricemia. We assume that UA is an equivalent to hydroquinone or p-aminophenol, which can be oxidized to quinone/quinoimine and thus acts as a radical scavenger. Based on this hypothesis, a series of UA analogs was designed and synthesized. In the chemical radical scavenging assay, active compounds were considered as hydroquinone or p-aminophenol equivalents. A highly functionalized UA structure is not essential to have radical scavenging activity. Potent active 5-hydroxyindolinones (1a, 2a, and 3a) showed sufficient activity with high solubility and low cytotoxicity.