Anti-inflammatory activity of compounds isolated from <i>Swertia mussotii</i>

<p>Six compounds were isolated from an ethanol extract of <i>Swertia mussotii</i> and identified as 2-phenylethyl-β-D-glucoside (<b>1</b>), amaroswerin (<b>2</b>), 1,3,7,8-tetrahydroxyxanthone (<b>3</b>), swertiamarine (<b>4</b>), 1,3,8-trihydroxy-5-methoxyxanthone (<b>5</b>) and methylswertianin (<b>6</b>). Compounds <b>1</b>, <b>2</b> and <b>6</b> were isolated from <i>S. mussotii</i> for the first time. The anti-inflammatory activities of the compounds were evaluated by determining their effect on the production of NO by LPS-stimulated RAW264.7 cells. Amaroswerin was the most potent inhibitor of NO release, with an IC<sub>50</sub> value of 5.42 μg/mL. Treatment with amaroswerin inhibited expression of iNOS at both protein and mRNA levels. Amaroswerin also dose-dependently suppressed production of TNF-α, IL-6 and IL-1β and reduced expression of mRNA for these LPS-stimulated pro-inflammatory mediators. Amaroswerin thus inhibits the expression of iNOS, TNF-α, IL-6 and IL-1β by downregulating transcription in LPS-induced RAW264.7 macrophage cells, indicating that amaroswerin may be a valuable therapeutic agent for the treatment of inflammatory diseases.</p>