Browsing Faculty of Science & Technology (FST) by Author "Dagne, Ermias"

Now showing items 1-10 of 10

    • Alkaloids of Teclea nobilis 

      Yenesew, Abiy; Dagne, Ermias (University of NairobiCollege of Biological and Physical Sciences, 1988)
      A new furoquinoline alkaloid to which we have assigned the trivial name nobiline, and seven other quinonline alkaloids were isolated and identified from the leaves and fruits of Teclea nobilis, an African medicinal plant.

    • Anthraquinones and chemotaxonomy of the asphodelaceae 

      Dagne, Ermias; Yenesew, Abiy (University of NairobiDepartment of Chemistry, Addis Ababa UniversityCollege of Biological and Physical Sciences,University of Nairobi, 1994)
      Phytochemical investigations on three genera of the Asphodelaceae, Aloe, KniphoJla and Bulbine showed that 1-methyl-8-hydroxyanthraquinones and anthrone-C-glycosides are characteristic constituents of the genus Aloe, ...

    • Chemotaxonomic significance of anthraquinones in the roots of asphodeloideae (asphodelaceae) 

      Van Wyk, Ben-Erik; Yenesew, Abiy; Dagne, Ermias (1995)
      The distribution of seven anthraquinones in the roots of some 46 species belonging to the genera Asphodelus, Asphodeline, Bulbine, Bulbinella and Kniphofia was studied by TLC and HPLC, 1,8-Dihydroxyanthraquinones based on ...

    • The chemotaxonomic significance of root anthraquinones and pre-anthraquinones in the genus Lomatophyllum (asphodelaceae) 

      Van Wyk, Ben-Erik; Yenesew, Abiy; Dagne, Ermias (University of NairobiDepartment of Chemistry, Addis Ababa UniversityDepartment of Botany, Rand Afrikaans UniversityCollege of Biological and Physical Sciences,University of Nairobi, 1995-11)
      The roots of seven species of Lomatophyllum were analysed by TLC and HPLC for the presence of nine different anthraquinones and pre-anthraquinones which are all known to be characteristic constituents of the subterranean ...

    • Chemotaxonomic survey of anthraquinones and pre-anthraquinones in roots of Aloe species 

      Van Wyk, Ben-Erik; Yenesew, Abiy; Dagne, Ermias (University of NairobiCollege of Biological and Physical Sciences, 1995-04)
      Root samples from 172 species of Aloe were surveyed by TLC and HPLC for the presence of anthraquinones and pre-anthraquinones. With the exception of the three species of the series Serrulatae, 1,8-Dihydroxyanthraquinones ...

    • A comparative study of anthraquinones in rhizomes of Kniphofia species 

      Yenesew, Abiy; Wondimu, Assefa; Dagne, Ermias (University of NairobiDepartment of Chemistry, Addis Ababa UniversityCollege of Biological and Physical Sciences,University of Nairobi, 1988-01-14)
      The anthraquinone content of eight kniphofia species was compared using reversed phase HPLC method coupled with a photodiode array detector.

    • Flavonoids and isoflavonoids from Tephrosia fulvinervis and Tephrosia pentaphylla 

      Dagne, Ermias; Yenesew, Abiy; Waterman, Peter G (University of NairobiCollege of Biological and Physical Sciences, 1989)
      From the roots, leaves and pods of Tephrosia pentaphylla three new 6-oxygenated rotenoids (dihydrostemonal, 9-demethyldihydrostemonal and 6-acetoxydihydrostemonal) were isolated and characterized. In addition six known ...

    • Flavonoids from the seed pods of Tephrosia pumila 

      Yenesew, Abiy; Dagne, Ermias; Waterman, Peter G (University of NairobiDepartment of Chemistry, Addis Ababa UniversityPhytochemistry Research Laboratories, Department of Pharmacy (Pharm. Chem.), University of StrathclydeCollege of Biological and Physical Sciences,University of Nairobi, 1989)
      Inaddition to the known pumilaisoflavones A and B two further isoflavonoids have been isolated from the seed pods of Tephrosia pumila collected in Ethiopia. These have been characterized, on the basis of spectral analysis, ...

    • Knipholone anthrone from Kniphofia foliosa 

      Dagne, Ermias; Yenesew, Abiy (University of NairobiCollege of Biological and Physical Sciences, 1993-11)
      A new anthrone named knipholone anthrone was isolated from the stem of Kniphofia foliosa. Its structure was determined by spectral analysis as well as conversion to knipholone.

    • Three steroidal alkaloids from Buxus hildebrandtii 

      Rahman, Atta-ur; Alam, Muzaffar; Nasir, Habib; Dagne, Ermias; Yenesew, Abiy (University of NairobiDepartment of Chemistry, Addis Ababa UniversityCollege of Biological and Physical Sciences,University of NairobiResearch Institute of Chemistry, University of Karachi, 1990)
      From the leaves of Buxus hildebrandtii three new steroidal alkaloids have been isolated and their structures determined by spectroscopic analysis. The following derived names have been suggested for these new alkaloids: ...