Abstract
Oxidative stress results from an overabundance of reactive oxygen species in the body, including free radicals, that can damage cells and DNA. Due to the increasing prevalence of oxidative stress-based diseases, such as cardiovascular disease, inflammation, dermatitis, and cancer, there is a growing need for the development of new antioxidants. In this study, sixteen hybrid molecules containing two known antioxidant moieties, hydroxy chromene and hydrazone, were synthesized and evaluated for free radical scavenging activity. Synthesis of the chromene hydrazones was achieved in two steps: 1) base-promoted chromenylation of 2,4-dihydroxybenzaldehyde with 3-methylbutenal to yield 2H-2,2-dimethyl-5-hydroxy-6-formylchromene, and 2) condensation of the chromene with substituted benzohydrazides and benzenesulfonyl hydrazide. The hydrazones were purified by column chromatography or recrystallization, and characterized by NMR and IR spectroscopy. The antioxidant capacity of the chromene and chromene hydrazones (0.125 mM) was determined by the DPPH assay. In this assay, the radical diphenylpicrylhydrazyl (DPPH) is reduced by the antioxidant, resulting in a decrease in absorbance at 515 nm, observed by UV-Visible spectroscopy. Most of benzohydrazone derivatives showed 10-30% radical scavenging activity, compared to butylated hydroxyanisole (BHA), which showed 81% inhibition. In contrast, the sulfonylhydrazone derivative showed comparable (77%) activity to BHA.