Soy protein-derived ACE-inhibitory peptide LSW (Leu-Ser-Trp) shows anti-inflammatory activity on vascular smooth muscle cells

Soy proteins are a rich source of various bioactive peptides. LSW (Leu-Ser-Trp) was previously identified from thermolysin-digested soy protein hydrolysate as a potent ACE-inhibitory peptide; however, its biological effects on vascular cells have not been elucidated. The present study evaluated anti-oxidant and anti-inflammatory activities of LSW on vascular smooth muscle cells (VSMCs). Ang II promoted oxidative stress and inflammation in VSMCs; adding LSW did not show anti-oxidant activity, while COX-2, but not iNOS, was down-regulated in Ang II-stimulated VSMCs, suggesting its anti-inflammatory activity. AT1R mediates most of the pathological effects of Ang II in VSMCs; LSW down-regulated Ang II-stimulated AT1R expression, via decreased phosphorylation of both Src and ERK1/2. Furthermore, LSW could also reduce the phosphorylation of nuclear transcription factor p50, but not p65. Results of this study suggested a novel function of LSW as an anti-inflammatory agent on VSMCs, which might broaden its uses as functional food ingredients. (C) 2017 Elsevier Ltd. All rights reserved.