Lipopolysaccharide로 자극된 RAW264.7 대식세포에서 연자육 단백질의 항염증 및 항산화 활성

Abstract

Lotus seeds have long been used as food and medicines in Asia. The object of this study was to investigate the potential anti-inflammatory and antioxidant activity of lotus seed protein (LSP), LSP hydrolysates. Lotus seed was defatted by hexane treatment followed by removal of phenolic compounds with ethanol extraction. LSP was isolated from the residue by alkaline solubilization at pH 10 and recovered by centrifugation followed by lyophilization. LSP hydrolysates were prepared by alcalase (pH 8, 50℃), pepsin (pH 2, 37℃) and combinations. The antioxidant activities of LSP, LSP hydrolysates were evaluated by DPPH radical scavenging, ABTS+ radical scavenging, ORAC value and lipid peroxidation inhibition. In the other experiment except ORAC assay, LSP showed the best antioxidant activity when LSP and LSP hydrolysates were compared. Additionally anti-inflammatory and antioxidant activities of LSP were measured in LPS-stimulated RAW264.7 macrophages. The NO production in LPS-stimulated RAW264.7 macrophages was significantly increased whereas co-treatment with LSP reduced NO production in a dose-dependent manner. LSP treatment also inhibited the production of TNF-α and IL-6 in LPS-stimulated RAW264.7 macrophages. The expression of iNOS, COX-2, MAPK, and NF-κB expression were also inhibited. We further examined antioxidant activity of LSP in LPS-stimulated RAW264.7 macrophages by measuring ROS production and antioxidant enzyme activities. ROS was increased by LPS stimulation and reduced by co-treatment with LSP. Antioxidant enzyme activities were increased only by catalase, but SOD did not show significant results. Therefore, LSP can be applied to the development of natural antioxidants and anti-inflammatory agents.