Dammarane Glycosides from the Root of <i>Machilus yaoshansis</i>

Nine new dammarane triterpene glycosides (<b>1</b>–<b>3</b> and <b>8</b>–<b>13</b>) and 12 known analogues have been isolated from an ethanol extract of the roots of <i>Machilus yaoshansis</i>. Compounds <b>1</b>–<b>7</b> have an uncommon 20,23-dihydroxydammar-24-en-21-oic acid-21,23-lactone moiety that was previously reported in compounds isolated from <i>Gynostemma pentaphyllum</i>. The configurations of the lactone moieties in <b>1</b>–<b>3</b> were determined by comparison of the experimental ECD spectra of <b>1</b>–<b>3</b> and the hydrolysates, <b>1a</b> and <b>1b</b>, with the corresponding calculated ECD spectra. On the basis of NMR and ECD data analysis of <b>1</b>–<b>7</b>, the previously reported C-20 and C-23 configurations of <b>4</b>–<b>7</b> and related derivatives from <i>Gynostemma pentaphyllum</i> were revised. In addition, the application of NMR data and Cotton effects to the determination of the relative and absolute configurations of the γ-lactone moiety in 3β,20,23-trihydroxydammar-24-en-21-oic acid-21,23-lactone derivatives is discussed

Yaoshanenolides A and B: New Spirolactones from the Bark of <i>Machilus yaoshansis</i>

Two novel tricyclic spirolactones bearing long linear alkyl chains, yaoshanenolides A (<b>1</b>) and B (<b>2</b>), formed by Diels–Alder[4 + 2] cycloaddition of a molecule of each butenolide with β-phellandrene, were isolated from the bark of <i>Machilus yaoshansis</i>. Their structures and absolute configurations were determined by extensive spectroscopic methods, especially 2D NMR and ECD data analysis. The proposed biosynthetic pathway is discussed. Both compounds exhibited nonselective cytotoxic activities against several human cancer cell lines