title: Labdane diterpenes of Leonurus sibiricus.
abstract: Seven new labdane diterpenes, sibiricinones A-E (1-4, 6) and 15-epi-sibiricinones D and E (5 and 7), and the flavone genkwanin were isolated from the aerial parts of Leonurus sibiricus. Sibiricinone D (4) and 15-epi-sibiricinone D (5), and sibiricinone E (6) and 15-epi-sibiricinone E (7), respectively, were isolated as C-15 epimeric pairs. These secondary metabolites were identified on the basis of 1D and 2D NMR including (1)H-(1)H COSY, HSQC, and HMBC spectroscopic techniques. The stereochemical configurations of compounds 4-7 were assigned through 2D T-ROESY and selective NOE experiments.
authors.affiliation: Laboratory of Bioorganic Chemistry, Department of Biological and Chemical Sciences, University of the West Indies, Cave Hill Campus, Bridgetown, Barbados.
authors.forename: Dionne M
authors.initials: DM
authors.lastname: Boalino
authors.forename: Stewart
authors.initials: S
authors.lastname: McLean
authors.forename: William F
authors.initials: WF
authors.lastname: Reynolds
authors.forename: Winston F
authors.initials: WF
authors.lastname: Tinto
mesh_terms: D001460:Barbados; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification*; D031332:Leonurus / Q000737:chemistry*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010946:Plants, Medicinal / Q000737:chemistry*
chemical_list: D004224:Diterpenes