Leopersin E and further labdane typ diterpenes from Leonurus cardiaca L.

Following the development of primary and refined antiarrhythmic extracts of Leonurus cardiaca L. [1] our main task was to search for possible cardioactive or cardiotoxic single constituents. In this context the paper attendant is focused on the group of lipophilic labdane type diterpenes. Via combination of normal and reversed phase column chromatography, it was possible to isolate three furanolabdanes from Leonurus cardiaca L., the structures of those have been determined mainly by 1d/2d 1H/13C NMR spectroscopic experiments. Leopersine E, which has been only once reported in Leonurus persicus [2], could be foun…