Browsing Faculty of Science & Technology (FST) by Author "Yenesew Abiy."

Now showing items 1-19 of 19

    • 7a-O-methyldeguelol, a modified rotenoid with an open ring-C, from the roots of Derris trifoliata 

      Yenesew Abiy.; Mushibe,EK.; Induli M.; Derese Solomon.; Midiwo Jacob O.; Kabaru JM.; Heydenreich M.; Koch A.; Peter MG. (Department of Chemistry, University of NairobiDepartment of Zoology, University of Nairobi,Institut für Chemie, Universität Potsdam, P.O. Box 601553, D-14415 Potsdam, Germany, 2005-03)
      From the acetone extract of the roots of Derris trifoliata an isoflavonoid derivative, named 7a-O-methyldeguelol, a modified rotenoid with an open ring-C, representing a new sub-class of isoflavonoids (the sub-class is ...

    • Anti-plasmodial activities and X-ray crystal structures of rotenoids from Millettia usaramensis subspecies usaramensis 

      Yenesew Abiy.; Derese Solomon.; Midiwo Jacob O.; Oketch-Rabah Hellen A.; Lisgartena John.; Palmerc Rex.; Heydenreich Matthias.; Peter Martin G.; Akala Hose.; Wangui Julia.; Liyala Pamela.; Waters Norman C. (University of NairobiDepartment of Chemistry, University of NairobiDepartment of Pharmacology and Pharmacognosy, University of NairobiDepartment of Crystallography, Birkbeck College, University of London, 2003-10)
      The dichloromethane extract of the stem bark of Millettia usaramensis subspecies usaramensis showed anti-plasmodial activity against the chloroquine sensitive (D6) and chloroquine resistant (W2) strains of Plasmodium ...

    • Anti-plasmodial Activities Of Flavonoids From Erythrina Sacleuxii 

      Yenesew Abiy.; Andayi AW.; Derese Solomon.; Midiwo Jacob O.; Gitu Peter M.; Jondiko OJ.; Akala H.; Liyala P.; Wangui J.; Waters NC.; Heydenreich M.; Peter MG. (University of NairobiDepartment of Chemestry, 2006-02)
      The acetone extracts of the root bark and stem bark of Erythrina sacleuxii showed antiplasmodial activities against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum. Chromatographic ...

    • Anti-plasmodial flavonoids from the stem bark of Erythrina abyssinica 

      Yenesew Abiy.; Induli Martha.; Derese Solomon.; Midiwo Jacob O.; Heydenreich Matthias.; Peter Martin G; Akala Hoseah.; Wangui Julia.; Liyala Pamela.; Waters Norman C. (Department of Chemistry, University of NairobiInstitut für Chemie, Universität Potsdam, GermanyUnited States Army Medical Research Unit-Kenya, USA, 2004)
      The ethyl acetate extract of the stem bark of Erythrina abyssinica showed anti-plasmodial activity against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC50 values of ...

    • Antimicrobial Activities of a New Schizozygane Indoline Alkaloid from Schizozygia coffaeoides and the Revised Structure of Isoschizogaline 

      Kariba R M.; Houghton P J.; Yenesew Abiy. (University of NairobiDepartment of Botany and Department of Chemistry,, 2002-04-21)
      Extracts from Schizozygia coffaeoides showed antimicrobial activity against fungal and bacterial species. Alkaloids isolated using bioassay-guided fractionation were isoschizogaline, schizogynine, and a new indoline alkaloid, ...

    • Antimicrobial and antiparasitic abietane diterpenoids from the roots of Clerodendrum eriophyllum 

      Derese Solomon.; Machumi F.; Samoylenko V.; Yenesew Abiy.; Midiwo Jacob O.; Wiggers FT.; Jacob MR; Tekwani BL.; Khan SI.; Walker LA.; Muhammad I. (University of NairobiCollege of biological and physical science, 2010-06)
      Chromatographic separation of the roots of a Kenyan medicinal plant, Clerodendrum eriophyllum, led to the isolation of ten abietane diterpenoids (1-10), one of which (1) was isolated for the first time from a natural source. ...

    • Antimicrobial flavonoids from the stem bark of Erythrina burttii 

      Yenesew Abiy.; Derese Solomon.; Midiwo Jacob O.; Bii CC.; Heydenreich M.; Peter MG. (University of NairobiCollege of bilogical and physical science, 2005-07)
      The chloroform extract of the stem bark of Erythrina burttii showed antifungal and antibacterial activities using the disk diffusion method. Flavonoids were identified as the active principles. Activities were observed ...

    • Antiparasitic and anticancer carvotacetone derivatives from Sphaeranthus bullatus 

      Machumi F.; Yenesew Abiy.; Midiwo Jacob O.; Heydenreich M.; Kleinpeter E.; Khan S.; Tekwani BL.; Walker LA.; Muhammad I. (Department of Chemistry, University of NairobI, 2012-09)
      The 1:1 MeOH/CH2Cl2 extract of aerial parts of Sphaeranthus bullatus, an annual herb native to tropical East Africa, showed activity against chloroquine sensitive D6 (IC50 9.7µg/ml) and chloroquine resistant W2 (IC50 ...

    • C-methylated and C-prenylated isoflavonoids from root extract of Desmodium uncinatum 

      Guchu Salome M.; Yenesew Abiy.; Tsanuo Muniru K.; Gikonyo Nicholas K.; Pickett John A.; Hooper Antony M.; Hassanali Ahmed. (University of NairobiDepartment of Chemistry, University of NairobiDepartment of Chemistry, Jomo Kenyatta University of Agriculture and TechnologyDepartment of Pharmacy and complementary/Alternative medicine, Kenyatta UniversityBiological Chemistry Division, Rothamsted Research, Harpenden,Herts A15 2JQ, UKInternational Centre of Insect Physiology and Ecology, 2007-03-05)
      A pterocarpan, 1,9-dihydroxy-3-methoxy-2-methylpterocarpan (named uncinacarpan) and two isoflavanones, 5,7-dihydroxy-2′,3′,4′-trimethoxy-6-(3-methylbut-2-enyl)isoflavanone (named uncinanone D) and 5,4′-dihydroxy-7,2′-dim ...

    • Effect of rotenoids from the seeds of Millettia dura on larvae of Aedes aegypti 

      Yenesew Abiy.; Derese Solomon.; Midiwo Jacob O.; Heydenreich M.; Peter M G. (University of NairobiDepartment of Chemistry, University of Nairobi, 2003-10)
      A crude chloroform extract of seeds of Millettia dura Dunn (Leguminosae) showed high activity (LC50 = 3.5 µg ml−1 at 24 h) against second-instar larvae of the mosquito, Aedes aegypti L (Diptera: Culicidae). The rotenoids, ...

    • Flavones and phenylpropenoids in the surface exudate of Psiadia punctulata 

      Jumaa Benard F.; Yenesew Abiy.; Midiwo Jacob O.; Waterman Peter G. (University of NairobiDepartment of Chemistry, University of Nairobi, 2001-06)
      Three flavones, 5,7-dihydroxy-2′,3′,4′,5′-tetramethoxyflavone, 5,4′-dihydroxy-7,2′,3′,5′-tetramethoxyflavone, and 5,7,4′-trihydroxy-2′,3′,5′ -trimethoxyflavone were isolated from the leaf exudate of Psiadia punctulata, ...

    • Flavonoids and isoflavonoids of Erythrina burttii 

      Martin G. Peter.; Yenesew Abiy.; Heydenreich Matthias.; Guchu Salome M.; lrungu Beatrice.; Derese Solomon.; Midiwo Jacob O. (Department of Chemistry, University of Nairobi,lnstitut fur Chemie, Universitat Potsdam, 2009)
      From the stem bark and root bark of Erythrina burttii twenty-three flavonoids and isoflavonoids, including some eight new compounds, have been isolated and characterised. The stem bark of this plant mainly produces isoflavanones ...

    • Flavonoids and Isoflavonoids with Antiplasmodial Activities from the Root Bark of Erythrina abyssinica 

      Yenesew Abiy.; Derese Solomon.; Irungu Beatrice.; Midiwo Jacob O.; Waters Norman C.; Liyala Pamela.; Akala Hoseah.; Heydenreich Matthias.; Peter Martin G. (University of NairobiDepartment of Chemistry, University of Nairobi, 2003-07)
      From the root bark of Erythrina abyssinica a new pterocarpene [3-hydroxy-9-methoxy-10-(3,3-dimethylallyl)pterocarpene] and a new isoflav-3-ene [7,4′-dihydroxy-2′,5′-dimethoxyisoflav-3-ene] were isolated. In addition, the ...

    • Investigation of some medicinal plants traditionally used for treatment of malaria in Kenya as potential sources of antimalarial drugs. 

      Derese Solomon.; Muthaura CN.; Keriko JM.; Yenesew Abiy.; Rukunga GM. (University of NairobiCollege of biological and physical science, 2011-03)
      Malaria is a major public health problem in many tropical and subtropical countries and the burden of this disease is getting worse, mainly due to the increasing resistance of Plasmodium falciparum against the widely ...

    • Preliminary studies on antipyretic and analgesic properties of Taverniera abyssinica 

      Dagne E.; Yenesew Abiy.; Capasso F.; Mascolo N.; Pinto A. (University of NairobiCollege of Biological and Physical Sciences,University of Nairobi, 1990-10)
      In an attempt to ascertain the pharmacological basis of the use of the marketed traditional drug Taverniera abyssinica A. Rich. (Amharic name Dingetegna), crude extracts as well as purified substances of this plant were ...

    • Three isoflav-3-enes and a 2-arylbenzofuran from the root bark of Erythrina burttii 

      Yenesew Abiy.; Midiwo Jacob O.; Guchua Salome M.; Heydenreich Matthias.; Peter Martin G. (University of NairobiDepartment of Chemistry, University of Nairobi, 2002-02)
      From the root bark of Erythrina burttii three isoflav-3-enes, 7,4′-dihydroxy-2′-methoxy-6-(1″,1″-dimethylallyl)isoflav-3-ene (trivial name, burttinol-A), 4′-hydroxy-2′-methoxy-2″,2″-dimethylpyrano[5″,6″:8,7]isoflav-3-ene ...

    • Two isoflavanones from the stem bark of Erythrina sacleuxii 

      Yenesew Abiy.; Midiwo Jacob O.; Heydenreich Matthias.; Schanzenbach Dirk.; Peter Martin G. (University of NairobiDepartment of Chemistry, University of Nairobi, 2000-11)
      From the stem bark of Erythrina sacleuxii two new isoflavanones, (R)-5,7-dihydroxy-2′,4′,5′-trimethoxyisoflavanone (trivial name, (R)-2,3-dihydro-7-demethylrobustigenin) and (R)-5-hydroxy-2′,4′,5′-trimethoxy-2″,2″-dimeth ...

    • Two unusual rotenoid derivatives, 7a-O-methyl-12a-hydroxydeguelol and spiro-13-homo-13-oxaelliptone, from the seeds of Derris trifoliata 

      Yenesew Abiy.; Kiplagat JT.; Derese Solomon.; Midiwo Jacob O.; Kabaru JM.; Heydenreich M.; Peter MG. (Department of Zoology, University of Nairobi,Department of Chemistry, University of NairobiInstitut für Chemie, Universität Potsdam, P.O. Box 601553, D-14415 Potsdam, Germany, 2006-05)
      The crude methanol extract of the seeds of Derris trifoliata showed potent and dose dependent larvicidal activity against the 2nd instar larvae of Aedes aegypti. From this extract two unusual rotenoid derivatives, a ...

    • Vangueria infausta root bark: in vivo and in vitro antiplasmodial activity 

      Abosl AO.; Mbukwa E.; Majinda RR.; Raserok BH.; Yenesew Abiy.; Midiwo Jacob O.; Akala H.; Liyala P.; Waters NC. (University of NairobiDepartment of Biological Sciences, University of BotswanaCollege of Biological and Physical Sciences,University of Nairobi, 2006)
      Vangueria infausta burch subsp. infausta (Rubiaceae) produces fruits eaten by humans and animals. The leaf, fruit, stem bark and root bark are used as a remedy for many ailments and the roots are used to treat malaria. In ...