Synthesis of novel caffeic acid derivatives and their protective effect against hydrogen peroxide induced oxidative stress via Nrf2 pathway.

Aim: This study was aimed to synthesize novel caffeic acid derivatives and evaluate their potential applications for the treatment of oxidative stress associated disease.

Main Methods: Caffeic acid sulfonamide derivatives were synthesized by coupling sulfonamides to the backbone of caffeic acid and fully characterized by melting point test, FT-IR, MS, NMR, UV-vis and n-octanol-water distribution assay. Their free radical scavenging ability was evaluated using DPPH assay and cytotoxicity against A549 cells were determined by MTT assay. The protective effect of these derivatives against hydrogen peroxide (HO) induced oxidative injury was assessed in A549 cells from cell viability, production of reactive oxygen species (ROS) and malondialdehyde (MDA), alternation of antioxidase activities, and expressions of Nrf2 and its target genes.

Key Findings: Six novel caffeic acid sulfonamide derivatives were obtained. The derivatives showed better liphophilicity than the parent caffeic acid. CASMZ, CAST and CASQ exhibited similar DPPH scavenging capability as caffeic acid, while the protection of hydroxyl groups on the benzene ring with acetyl groups caused decrease in radical scavenging activity. No inhibitory effect on the proliferation of A549 cells were observed up to a concentration of 50 μM. Pre-treatment of cells with these derivatives strongly inhibited HO induced decrease of cell viability, reduced the production of ROS and MDA, promoted antioxidase activities, and further upregulated the expression of Nrf2 and its target genes.

Significance: Caffeic acid sulfonamide derivatives were synthesized with simple reactions under mild conditions. They might protect cells from HO-induced oxidative injury via Nrf2 pathway.