Anti-inflammatory Effect of Wild Indigo (Baptisia tinctoria) Root on Raw 264.7 Cells with Stimulated Lipopolysaccharide

This study tested the anti-inflammatory effect of wild indigo (Baptisia tinctoria) root in Raw 264.7 cells. We prepared two extracts of B. tinctoria: one in water and the other in 50% ethanol. Then we evaluated the toxicities of the B. tinctoria root extracts at 10 to 100 mg mL^-1 concentrations in Raw 264.7 cells and observed 80% cell viability. An anti-inflammatory effect of B. tinctoria root extract in lipopolysaccharide (LPS)-stimulated Raw 264.7 cells was observed with concentrations of 10, 30, and 50 µg·mL^-1. The results showed that 77.27–66.82% of nitric oxide (NO) production was inhibited by 50 µg·mL^-1 B. tinctoria root extract. The protein expression of inducible NO synthase (iNOS) expression dramatically decreased by 93.14% and 52.65% in Raw 264.7 cells treated with water and ethanol extracts of B. tinctoria root, respectively. Moreover, cyclooxygenase-2 (COX-2) protein expression decreased by 42.85% and 69.70% in Raw 264.7 cells treated with water and ethanol extracts of B. tinctoria root, respectively. Furthermore, the mRNA expression of pro-inflammatory markers, such as tumor necrosis factor alpha, interleukin-1β, interleukin-6, monocyte chemoattractant protein-1, and prostaglandin E synthase 2, was significantly suppressed in a concentration-dependent manner. Additionally, the B. tinctoria root extracts effectively inhibited enzymes involved in physiological activities. The B. tinctoria root extracts showed excellent anti-inflammatory effects and can be used as a functional material for biological activities.