Lotus (Nelumbo nucifera) seed protein isolate exerts anti-inflammatory and antioxidant effects in LPS-stimulated RAW264.7 macrophages via inhibiting NF-κB and MAPK pathways, and upregulating catalase activity.

Lotus seed has long been used in traditional medicine and cuisine. In this study, lotus seed protein (LSP) was isolated and evaluated its anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. LSP isolate (LSPI) treatment in LPS-stimulated RAW264.7 macrophages resulted in the significant (p < 0.05) decrease of NO production by downregulation of the expressions of mRNA and protein, including inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). In addition, LSPI treatment attenuated the production of reactive oxygen species (ROS) through increasing catalase activity, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1β in LPS-stimulated RAW264.7 macrophages. Furthermore, LPS stimulation in RAW264.7 macrophages caused the translocation of nuclear factor-kappa B (NF-κB) into the nucleus and the phosphorylation of mitogen-activated protein kinase (MAPK) but these stimulations were abolished by LSPI treatment.