| Autor: |
Tshitenge DT; Institute of Organic Chemistry , University of Würzburg , Am Hubland , D-97074 Würzburg , Germany.; Faculty of Pharmaceutical Sciences , University of Kinshasa , B.P. 212 Kinshasa XI, Democratic Republic of the Congo.; Medicinal Chemistry , Bayer AG, Pharmaceuticals , Aprather Weg 18a , D-42096 Wuppertal , Germany., Bruhn T; Institute of Organic Chemistry , University of Würzburg , Am Hubland , D-97074 Würzburg , Germany.; Federal Institute for Risk Assessment , Max-Dohrn-Straße 8-10 , D-10589 Berlin , Germany., Feineis D; Institute of Organic Chemistry , University of Würzburg , Am Hubland , D-97074 Würzburg , Germany., Schmidt D; Institute of Organic Chemistry , University of Würzburg , Am Hubland , D-97074 Würzburg , Germany., Mudogo V; Faculté des Sciences , Université de Kinshasa , B.P. 202 , Kinshasa XI, Democratic Republic of the Congo., Kaiser M; Swiss Tropical and Public Health Institute , Socinstrasse 57 , CH-4002 Basel , Switzerland.; University of Basel , Petersplatz 1 , CH-4003 Basel , Switzerland., Brun R; Swiss Tropical and Public Health Institute , Socinstrasse 57 , CH-4002 Basel , Switzerland.; University of Basel , Petersplatz 1 , CH-4003 Basel , Switzerland., Würthner F; Institute of Organic Chemistry , University of Würzburg , Am Hubland , D-97074 Würzburg , Germany., Awale S; Division of Natural Drug Discovery, Institute of Natural Medicine , University of Toyama , 2630 Sugitani , Toyama 930-0194 , Japan., Bringmann G; Institute of Organic Chemistry , University of Würzburg , Am Hubland , D-97074 Würzburg , Germany. |
| Abstrakt: |
From the twigs and leaves of the Central African liana Ancistrocladus ealaensis (Ancistrocladaceae), a series of ten 7,8'-coupled naphthylisoquinoline alkaloids were isolated, comprising eight new compounds, named ealamines A-H ( 4a , 4b , 5 - 10 ), and two known ones, 6- O -demethylancistrobrevine A ( 11 ) and yaoundamine A ( 12 ), which had previously been found in related African Ancistrocladus species. Only one of the new compounds within this series, ealamine H ( 10 ), is a typical Ancistrocladaceae-type alkaloid, with 3 S -configuration at C-3 and an oxygen function at C-6, whereas seven of the new alkaloids are the first 7,8'-linked "hybrid-type" naphthylisoquinoline alkaloids, i.e., 3 R -configured and 6-oxygenated in the tetrahydroisoquinoline part. The discovery of such a broad series of 7,8'-coupled naphthyltetrahydroisoquinolines is unprecedented, because representatives of this subclass of alkaloids are normally found in Nature quite rarely. The stereostructures of the new ealamines were assigned by HRESIMS, 1D and 2D NMR, oxidative degradation, and experimental and quantum-chemical ECD investigations, and-in the case of ealamine A ( 4a )-also confirmed by X-ray diffraction analysis. Ealamines A-D exhibited distinct-and specific-antiplasmodial activities, and they displayed pronounced preferential cytotoxic effects toward PANC-1 human pancreatic cancer cells in nutrient-deprived medium, without causing toxicity under normal, nutrient-rich conditions, with ealamine C ( 5 ) as the most potent agent. |
