Browsing by Author "Nkunya, Mayunga H.H."

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    Geranylbenzoquinonoids from Lettowianthus stellatus fruits
    (Taylor & Francis, 2010) Makangara, John J.; Nkunya, Mayunga H.H.; Jonker, Stephan S.
    The geranylbenzoquinonoids 7-(3,7-dimethylocta-2,6-dienyl)-5-hydroxy-3H-benzofuran-2-one (lettowienolide), dimethyl 2,3-bis-[5-(3,7-dimethylocta-2,6-dienyl)-3,6-dioxocyclohexa-1,4-dienyl]-succinate (lettowiquinone), 2-(3,7-dimethylocta-2,6-dienyl)-6-[7-(3,7-dimethylocta-2,6-dienyl)-5-hydroxybenzofuran-2-yl]-[1,4]benzoquinone (lettowifuraquinone), methyl [3-(3,7-dimethylocta-2,6-dienyl)-6-methyl-5-(3-methylbut-2-enyl)-1,4-dioxo-1,5, 8,8a-tetrahydro-4H-nathphalen-4a-yl)]-acetate (lettowinone) and methyl [6-hydroxy-2-methyl-2-(4-methylpent-3-enyl)-2H-chromen-8-yl]-acetate (lettowipyraquinol) were isolated from fruits of Lettowianthus stellatus Diels, together with juvenile hormone III and 7-octadecen-9-ynoic acid. Lettowienolide and lettowiquinone exhibited mild in vitro activity against the Plasmodium falciparum malaria parasite (each IC50 ∼ 20 µg mL−1). Structural determination was achieved based on extensive analysis of spectroscopic data.
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    Prenylindoles from Tanzanian Monodora and Isolona Species
    (Taylor & Francis, 2004) Nkunya, Mayunga H.H.; Makangara, John J.; Jonker, Stephan A.
    6-(3-Methyl-but-2-enyl)-1,3-dihydro-indol-2-one, annonidine F [3-[6-(3-methyl-but-2-enyl)-1H-indolyl]-6-(3-methyl-but-2-enyl)-1H-indole], 1H-indole-5-carbaldehyde, 6-(3-methyl-2-butenyl)-1H-indole, 6-(3-methylbuta-1,3-dienyl)-1H-indole, 6-(4-oxo-but-2-enyl)-1H-indole and 3-geranylindole were isolated from Monodora angolensis (Annonaceae) while 3-(1,1-dimethyl-but-2-enyl)-5-(3-methyl-but-2-enyl)-1H-indole (caulidine A), 4-[3-(1,1-dimethyl-but-2-enyl)-1H-indol-5-yl]-but-3-en-2-one (caulidine B), 5-(3-methyl-2-butenyl)-1H-indole and 5-(3-methylbuta-1,3-dienyl)-1H-indole were obtained from Isolona cauliflora (Annonaceae); structural determination by spectroscopic analysis. Some of the prenylindoles had antifungal and antimalarial activities.