Abstract: The invention provides a method for preventing or reducing the effects of oxidative stress on a substrate. The method includes the step of treating the substrate with a compound of formula (I), or a pharmaceutically acceptable salt thereof, wherein: R1 is one or more substituents selected from —H, -alkyl, -alkoxy, -aryl, -aryloxy, -halogen, -amino (mono-, di- and tri-substituted), -alkylthio, —NO2, —COOH, —COOAlkyl, —CO-alkyl, —CN; R2 is one or more substituents selected from —H, -alkyl, —(CH2CH2O)n-R5, a sugar moiety; R3 is —H, -alkyl, -aryl, -alkylOR6, -alkylC(O)R6; R5 is selected from —H, -alkyl, -aryl; and R4 and R6 are independently selected from —OH, —O-alkyl, —O-polyalkyleneoxy, —O-aryl, —OC(O)O-alkyl, —S-alkyl and -amino.