Red Bean Extract Inhibits Lipopolysaccharide-Induced Inflammation and H₂O₂-Induced Oxidative Stress in RAW 264.7 Macrophages.

Red bean (Phaseolus radiatus L. var. Aurea) is a leguminous seed and mainly used as one of the popular ingredients in oriental desserts. The objective of this study was to evaluate the anti-inflammatory activity of 50 g/kg ethanolic extract of red bean (RBE) by measuring lipopolysaccharide (LPS)-induced expressions of nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in RAW 264.7 macrophages. On the other hand, the antioxidant activity of RBE was determined by thiobarbituric acid reactive substances method and comet assay using H2O2-induced macrophages. The results showed that RBE at the concentrations of 50-200 μg/mL can significantly suppress the inflammatory responses in LPS-stimulated macrophages through the reduction of cellular NO and downregulation of the gene expressions of iNOS, COX-2, TNF-α, and IL-6 in a dose-dependent manner. Furthermore, RBE can diminish H2O2-induced oxidative damage in RAW 264.7 macrophage. Phenolic compounds and cyanidin-3-O-glucoside from BRE may have efficacy as overall in vitro anti-inflammatory and antioxidant agents. Red bean exerts an anti-inflammatory response and has potential as a health-promoting ingredient.