Synthesis and Evaluation of 4-Hydroxyphenylacetic Acid Amides and 4-Hydroxycinnamamides as Antioxidants

4-Hydroxyphenylacetic acid amides and 4-hydroxycinnamamides were synthesized and their antioxidant and neuroprotective activities were evaluated. Among the prepared compounds, 6f, 6g, 8b, and 9 exhibited potent inhibition of lipid peroxidation in rat brain homogenates, and marked DPPH radical scavenging activities. Furthermore, 6f, 6g, and 9 exhibited neuroprotective action against the oxidative damage induced by the exposure of primary cultured rat cortical cells to H2O2, xanthine/xanthine oxidase, or Fe2+/ascorbic acid. Based on these results, we found that 6f was the most potent antioxidant among the compounds tested.