Effects of Ethanol Extracts from Commonly Consumed Vegetables by Koreans on NO, TNF-α and MCP-1 Production in LPS-stimulated RAW 264.7 Macrophages

Abstract

Korean dishes, Hansik is characterized by healthful vegetable intake. The purpose of this study was to evaluate the inhibitory effect of commonly consumed vegetables by Koreans on obesity/metabolic disease-related inflammation. Through statistical analysis of the KNHANES database (1st 1998, 5th 2010, 2011) and a literature review, we selected vegetables for study. Among the vegetables, main or sub ingredients of Kimchi were excluded. Samples were prepared using only edible portions and freezedried. After grinding, samples were extracted with ethanol, evaporated and finally lyophilized. The cytotoxicity of samples was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, at various concentrations that do not affect cell viability. Raw 264.7 macrophages were treated with lipopolysaccharide (LPS) and 11 kinds of samples or positive control (troglitazone) dissolved in dimethyl sulfoxide (DMSO). After 24 hours, nitric oxide (NO), tumor necrosis factor α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) production were determined. Excepts for young pumpkin and bracken, nine samples effectively reduced NO production compared with control treated with LPS and DMSO. NO levels of five samples (bean sprouts, leeks, eggplant, mugwort, and pumpkin) were similar to that of the positive control. These five samples showed significantly decreased TNF-α or MCP-1 compared to the control group. Our results suggest that consumption of commonly consumed vegetables contributes to partial prevention of obesity and related metabolic syndrome through reduction of NO, TNF-α, and MCP-1 production.