Abstract
Labdanes, leonurenones A-C, two known labdanes, luteolin 7-O-β-glucoside and luteolin were isolated and characterized from a commercial source of Leonotis leonurus. Genetic methods allowed for identification of the plant material. The leonurenones contain an uncommon α,β-unsaturated enone moiety in ring B, and leonurenones A and B were evaluated in a competitive inhibition assay at the GABA A neuroreceptor site.