Three undescribed coumarins from the roots of Angelica pubescens.

Three undescribed coumarins, 6-(3-hydroxy-3-methyl-2-oxobutyl)-7-methoxycoumarin (1), (R)-6-(1,3-dihydroxy-3-methyl-2-oxobutyl)-7-methoxycoumarin (2), angelol N (6), together with four known coumarins were isolated from the roots of Angelica pubescens. Their structures were determined by extensive spectroscopic analyses. The absolute configurations of compounds 2 and 6 were assigned via electronic circular dichroism (ECD). Their inhibitory effects on lipopoly-saccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 cells were evaluated. Compounds 1-4 exhibited moderate inhibitory activities.