Nine sesquiterpenes from <i>Solanum torvum</i>

<p>Three new sesquiterpenes, namely 3<i>β</i>,11-dihydroxy-4,14-oxideenantioeudesmane (<b>1</b>), 1<i>β</i>,10<i>β</i>,12,14-tetrahydroxy-<i>allo</i>-aromadendrane (<b>2</b>) and 1<i>β</i>,10<i>β</i>,13,14-tetrahydroxy-<i>allo</i>-aromadendrane (<b>3</b>), along with six known sesquiterpenes (<b>4</b>–<b>9</b>), were isolated from the roots of <i>Solanum torvum</i>. Compound <b>4</b> and <b>5</b> are epimers, their main difference lies in the C-11 configulation. Normally, epimers do not make a huge difference in C NMR spectra, but in this kind of structure of A, B, C rings, and C ring is sterically strained structure, stericall effects influence strongly the ¹³C NMR chemical shifts, when C-11 configulation changed, it makes a huge difference in the three ring of structure, such as C-6, C-7, C-11. New compound <b>2</b> and <b>3</b> are epimers and similar to compound <b>4</b> and <b>5</b>, their just increase a hydroxy in C-1 and have a same regular pattern in C NMR spectra, otherwise, compound <b>5</b> was firstly confirmed by single-crystal X-ray diffraction.