A new monoterpene and a new sesquiterpene from the roots of Ageratina adenophora

Abstract A new thymol type monoterpene, 2α-methoxyl-3β-methyl-6-(acetyl-O-methyl)-2,3-dihydrobenzofuran (1), and a new cadinane-type sesquiterpenoid, 1,6-dihydroxy-1-isopropyl-4,7-dimethyl-3,4-dihydronaphthalen-2(1H)-one (2), were isolated from the roots of Ageratina adenophora, along with four known compounds, eupatorenone (3), 3-hydroxymuurola-4,7(11)-dien-8-one (4), 9-oxoageraphorone (5) and (4R,5S)-4-Hydroxy-5-isopropyl-2-methyl-2-cyclohexehone (6). Their structures were determined by spectroscopic methods, including nuclear magnetic resonance (NMR) and mass spectrometry (MS) techniques. These compounds were all isolated from the roots of this plant for the first time. Compounds 1, 3 and 4 showed in vitro bacteriostatic activity against three test Gram-positive bacteria with MIC values ranging from 12.5 to 50 μg/mL. While, no obvious inhibitory activity was detected for the other compounds.