Zeitschrift für Phytotherapie 2013; 34 - P38
DOI: 10.1055/s-0033-1338240

Labdane-type diterpenes and other lipophilic constituents from cardioactive Leonurus cardiaca L.: Analytical and preparative chromatography as well as structural determination

A Brückner 1, L Hennig 2, HW Rauwald 1
  • 1University of Leipzig, Department of Pharmaceutical Biology, Johannisallee 21 – 23, 04103 Leipzig
  • 2University of Leipzig, Department of Chemistry, Institute for Organic Chemistry, Johannisallee 39, 04103 Leipzig

Continuing our search for possible cardioactive single constituents of primary and refined antiarrhythmic extracts of Leonurus cardiaca L. [1] we focused on the group of furanic labdane type diterpenes and other lipophilic compounds. The paper attended reports herewith the isolation of five diterpenes besides known lipophilic substances, like sitosterol, stigmasterol, genkwanin and ursolic acid. In accordance to Knöss et al. [2, 3] the postulated presence of leocardine [4] as a major reference substance of Leonurus cardiaca L. could not be confirmed. The structures of leopersine E, isoleosibirine, leopersine F and 7-epi-leopersine F were determined by 1 d/2 d 1H/13C NMR spectroscopical experiments. These labdane-type diterpenes have been found only once in other Leonurus species, namely in the related Lamiaceae L. sibiricus and L. persicus [5, 6]. A TLC-comparison of different Leonurus species showed a various range as well as highly different amounts of diterpenes.

Furthermore genkwanin, a lipophilic flavone, typical of different Leonurus species, was isolated which may be useful as a chemotaxonomic marker within the subfamily Lamioideae.

In view of the above mentioned search for possible cardioactive constituents, the similarity of these diterpenes to e.g. premarrubeine and marrubenol from the closely related Marrubium vulgare L. might be an important hint at a possible cardioactive property, particularly since those have been evaluated as calcium channel blocking agents [7].

References:

[1] Ritter M et al. Planta Med 2010; 76: 572 – 582

[2] Knöss W. Plant Cell Reports 1995; 14: 790 – 793

[3] Knöss W et al. Planta Med 1998; 64: 357 – 361

[4] Malakov P et al. Phytochemistry 1985; 24: 2341 – 2343

[5] Tasdemir D et al. J Nat Prod 1996; 59: 131 – 134

[6] Savona G et al. Phytochemistry 1982; 21: 2699 – 2701

[7] El Bardai S et al. Planta Med 2003; 69: 75 – 77