Meroterpenoids from <i>Rhododendron racemosum</i> and their anti-inflammatory activities

Three meroterpenoids, including one new compound, ranhuadujuanine E (<b>1</b>), one new natural product, methyl (<i>E</i>)-3-(3,7-dimethylocta-2,6-dien-1-yl)-2,4-dihydroxy-6-methylbenzoate (<b>2</b>), and one known compound, ranhuadujuanine D (<b>3</b>), along with two known sesquiterpenoids (<b>4</b>-<b>5</b>) were isolated from <i>Rhododendron racemosum</i>. Their structures were elucidated on the basis of extensive spectroscopic analysis, and the absolute configuration of C-6' in compound <b>1</b> was assigned by using Snatzke's method. Compounds <b>1</b>-<b>3</b> had inhibitory effects on LPS-induced NO release in RAW264.7 cells.