Lunasin and lunasin-like peptides inhibit inflammation through suppression of NF-κB pathway in the macrophage

Inflammation is part of the host defense mechanism against harmful matters and injury; however, aberrant inflammation is associated to the development of chronic diseases such as cancer. Lunasin is a novel peptide that demonstrates potential anticancer activity against mammalian cancer cell lines and may play a role in inflammation. The objective of this study was to determine the mechanism of action by which lunasin and lunasin-like peptides exert their anti-inflammatory properties using RAW 264.7 macrophage cell line as an in vitro model. We purified three peptides (5, 8, and 14 kDa) from defatted soybean flour with a positive immunoreactivity towards lunasin mouse monoclonal antibody. Treatment with these peptides (10-50 mu M) resulted in the inhibition of pro-inflammatory markers in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. The 5 kDa peptide inhibited most potently pro-inflammatory markers including interleukin-6 production (IC50 = 2 mu M), interleukin-1 beta production (IC50 = 13 mu M), nuclear factor-kappa B (NF-kappa B) transactivation (IC50 = 21 mu M), cyclooxygenase-2 expression (IC50 = 25 mu M), nitric oxide production (IC50 = 28 mu M), inducible nitric oxide synthase expression (IC50 = 37 mu M), prostaglandin E-2 production (IC50 = 41 mu M), p65 nuclear translocation (IC50 = 48 mu M) and p50 nuclear translocation (IC50 = 77 mu M). In conclusion, lunasin and lunasin-like peptides purified from defatted soybean flour inhibited inflammation in LPS-induced RAW 264.7 macrophage by suppressing NF-kappa B pathway. (C) 2009 Elsevier Inc. All rights reserved.