Ferulic acid but not alpha-lipoic acid effectively protects THP-1-derived macrophages from oxidant and pro-inflammatory response to LPS

Objective: The diet supplementation with antioxidants-rich products is a way to protect people from free radical-induced diseases. In this study, we compare the anti-inflammatory/antioxidant activity of two compounds available as supplements: alpha lipoic acid (ALA) and ferulic acid (FA). Materials and methods: The free radical scavenging capacity of ALA and FA in the cell free system was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Anti-inflammatory activity of both compounds was determined, in vitro, on THP-1 derived macrophages model, both resting (not stimulated) and inflammatory (lipopolysaccharide- or tumor-necrosis factor alpha-stimulated). Results: We have found that FA exhibits much higher radical scavenging activity than ALA, in cell free system. The functional assays demonstrated that although both ALA and FA limited the reactive oxygen species (ROS) formation in the presence of inflammatory macrophages, the latter acid was significantly more effective. Only FA reduced the release of pro-inflammatory interleukin 1 and interleukin 6 by lipopolysaccharide-treated macrophages. Neither FA nor ALA affected the viability of macrophages. Conclusion: Among those two compounds only FA has significant free radical scavenging activity in cell free system and acts as anti-inflammatory and antioxidant agent on macrophages. It can be assumed that application of FA in a diet can protect the host from the development and/or progression of inflammation.