High structural diversity of furanoid <i>ent</i> -labdanes from <i>Potamogeton lucens</i> L.

NMR chemical profiling of the freshwater <i>Potamogeton lucens</i> extract resulted in the identification of twelve undescribed (<b>1-12</b>) and six previously reported <i>ent-</i>labdanes (<b>13-17</b>). Compounds <b>1</b> to <b>12</b> were isolated and fully characterised by detailed spectroscopic analysis. These compounds are built of three different scaffolds of <i>trans</i>-decalin substructures associated with either a γ-hydroxy-butenolide or a butenolide moiety. Compounds <b>5</b> and <b>6</b> as well as <b>1</b> and <b>15</b> are pairs of stereoisomers at C4 position. Compounds <b>11</b> and <b>12</b> are respectively trinor- and nor-<i>ent-</i>labdanes. This work highlights the high chemical diversity of <i>P. lucens</i> and will serve as a basis for the investigation of other <i>Potamogeton</i> species.