Mitracarpus frigidus reduces lipid metabolism and PGE(2) levels in inflammatory cells

Objectives To evaluate the ability of the aqueous extract of Mitracarpus frigidus (MFAq) to inhibit lipid body formation and inflammatory mediator production in macrophages stimulated with lipopolysaccharide (LPS) and interferon gamma (IFN-gamma). Methods MFAq was chemically characterized by ultrafast liquid chromatography/quadruple time-of-flight tandem mass spectrometry. The macrophages obtained from mice were incubated with MFAq. Cell viability and membrane integrity were evaluated by 3-(4,5-dimethylthiazol2-yl)-2,5-diphenyltetrazolium bromide and propidium iodide assays, respectively. Moreover, NO, reactive oxygen species (ROS), transforming growth factor beta (TGF-ss), prostaglandin E2 (PGE(2)) levels and lipid bodies (LBs) were examined in macrophages that were stimulated with LPS and IFN-gamma and treated with MFAq. Finally, molecular docking analysis was conducted to investigate the interaction of MFAq with the cyclooxygenase 2 (COX-2) enzyme. Key findings Chlorogenic acid, clarinoside, harounoside, rutin, kaempferol-3O-rutinoside and 2-azaanthraquinone were identified in MFAq. MFAq significantly inhibited NO, ROS and LBs, and did not affect the membrane integrity of macrophages. MFAq-treated cells showed significantly lower levels of TGF-ss and PGE(2). Molecular docking demonstrated that the compounds found in MFAq are able to inhibit COX-2 by binding to important residues in the catalytic site. Conclusions MFAq interferes with lipid metabolism in stimulated macrophages, leading to the reduction of important inflammatory mediators. Furthermore, MFAq can directly inhibit the COX-2 enzyme or inhibit its expression owing to its ability to reduce NO production.