Anti-inflammatory effect and mechanism of action of ellagic acid-3,3′,4-trimethoxy-4′-<i>O</i>-α-L-rhamnopyranoside isolated from <i>Hopea parviflora</i> in lipopolysaccharide-stimulated RAW 264.7 macrophages

Abstract

Phytochemical investigation of the stem bark of <i>Hopea parviflora</i> resulted in the isolation of <b>9</b> compounds; which includes friedelin (<b>1</b>), friedelin-3<i>β</i>-ol (<b>2</b>), (-)-ampelopsin A (<b>3</b>), (-)-<i>ɛ</i>-viniferin (<b>4</b>), (-)-hopeaphenol (<b>5</b>), vaticaphenol A (<b>6</b>), 2,4,8-trihydroxyphenanthrene-2-<i>O</i>-glucoside (<b>7</b>), ellagic acid-3,3',4-trimethoxy-4'-<i>O</i>-α-L-rhamnopyranoside (<b>8</b>) and <i>β</i>-sitosterol-<i>β</i>-D-glucoside (<b>9</b>). Among them, compounds <b>1</b>, <b>2</b>, <b>6</b>, <b>7</b>, <b>8</b> and <b>9</b> are isolated for the first time from this species. Further, we evaluated the anti-inflammatory activity of compounds <b>4</b>, <b>5</b>, <b>6</b>, <b>7</b> and <b>8</b>. In this study, compound <b>8</b> inhibited the activity of proinflammatory mediators like NO, TNF-<i>α</i>, IL-6, 5-LOX and COX-2, also promoted the action of anti-inflammatory mediator like IL-10 <i>via</i> inhibition of the NF-κB pathway in LPS-stimulated RAW 264.7 macrophages.